August 2011

UNDERFLOOR HEATING & COOLING

Underfloor
heating and
cooling
sustainable solutions for
commercial, public and
residential buildings

Image courtesy of London 2012

Education

Front cover pictures,

left to right:
Athletes Village, London
Swiss Re building, London
B
 ritish Museum, London

Healthcare

This page,
top to bottom:
C
 astle Rock School,
Leicester
S
 t Thomas and Evelina
Hospital, London
P
 ool, University of East
Anglia, Norwich

Leisure

Opposite page,
top to bottom:
W
 estfield Shopping Centre Stratford, London
Swiss Re building, London
S
 cottish Parliament
building, Edinburgh
MOD Residential Housing

Warmafloor is at the leading edge of designing, manufacturing

Underfloor heating provides the most efficient and comfortable

and installing underfloor heating/cooling systems.

all-round warmth of any heating system, suitable for every type

We are an authoritative organisation, with a proven track

of building, large or small, new build or refurbishment.

record of success, spanning 25 years in delivering reliable, cost

Warmafloor is spearheading the continuing development of

effective solutions that reflect todays demand for sustainable

the UKs radiant floor heating industry. Its unique design and

construction.

installation expertise has led to Warmafloor systems being

installed in some of the UKs most prestigious and award
winning buildings, including landmark projects such as the
British Museum, Athletes Village, the A380 and A350 Airbus
factories, and the Scottish Parliament building.

Tel: 01489 581787 www.warmafloor.co.uk

Retail Centres

Contents
Introduction
Track record of sustainability

and success
Heating solutions

Cooling option

Geothermal/solar/heat pump options

How underfloor heating works

Benefits of underfloor heating

Commercial
Commercial, industrial &
public buildings
Considerations

Public Buildings

8 - 11

Case studies

12 - 16

Solid floor screeded systems

17 - 19

Structural concrete systems

20 - 21

Batten/sprung floor system

22 - 23

Floating floor system

24

Suspended floor systems

25

Raised Access Floor systems

26

Bespoke systems

27

Residential buildings
Case studies

28 - 29

Solid floor system

30

Floating and suspended

31

floor systems

Residential
Components
Polybutylene pipe

32 - 33

Underfloor manifolds & actuators

34 - 35

Screeds over underfloor heating

36 - 37

Typical Heating Schematic

38

Control systems

39

Warmafloor
capability responsibility sustainability

Track record of sustainability and success

Welcome to Warmafloor!

Our capability is second to none, offering a

Warmafloor

complete engineering service at every

team of skilled people

We pride ourselves in providing a unique

stage, from project design and product

total solution for the British building

manufacture, to system installation

industry. With a strong foundation of more

and commissioning.

than two decades of knowledge and

qualifications in every element of the

building industry
focus on developing and training our own

expertise, Warmafloor heating and

Aware of the industrys enormous growth

people (rather than using subcontractors) to

cooling systems provide total assurance

potential underfloor heating is the fastest

complete every job on time and on budget

for clients in the commercial, public and

growing sector of the heating industry we

private sectors.

ensure that Warmafloor continues to lead

the way through investing in technical
developments and training programmes for
the specifiers and installers of the future.

In our quest to be the best, we have

showcased all the Warmafloor heating and
cooling systems at our own Head Office
building.
Come and visit a warm welcome awaits you!
Mike Lamb
M.D. of Warmafloor and past Chairman
of UHMA (The Underfloor Heating Manufacturers
Association). Member of CIBSE.

Tel: 01489 581787 www.warmafloor.co.uk

Heating solutions
Warmafloor provides the complete underfloor heating solution
design, supply and installation for the entire project.
Image courtesy of London 2012

We believe we have more experience and capability in large and

complex projects than any other company in the UK.
Most of the systems we install are powered by modern HE
(High Efficiency) condensing boilers and controls, and we have
substantial expertise in ensuring optimum system operation and
energy efficiency. We have also developed considerable expertise
in working with systems powered by heat pumps and other forms
Athletes Village

of renewable energy.

Cooling option
Underfloor systems used to provide heating during winter months
can also be used to cool buildings in the summer.
By circulating cool, rather than warm water, the floor can be
cooled so as to offset high ambient temperatures and
solar gains.
At Warmafloor, we have the expertise to design and install cool
water systems that can utilise river water or ground water
as a cooling source, where convenient. By reducing the demand
Imperial War Museum

for air conditioning, we can further cut your energy costs and
carbon footprint.

Geothermal, solar and heat

pump options
At Warmafloor, we have developed expertise in designing and
installing systems that can harness geothermal energy and heat
pump systems for heating or cooling. Less expensive to operate
than other heating systems because they tap into heat in the
outdoor air, ground or water supply they provide a high CoP
(Coefficient of Performance) factor more heat than the equivalent
amount of electrical energy.
Banks of solar thermal panels may be installed to convert the suns
Gloucester Police HQ

radiant energy into hot water, even on the greyest winters day.
A traditional fossil fuelled boiler can then be used to top up the
heating as required. Warmafloors systems have the capability to
harness renewable energy sources, cut heating bills, and reduce
the carbon footprint.

How underfloor heating works

24oc

Systems with radiators

24oc

Radiators distribute heat by convection currents, which can result

in draughts and hot spots. The floor will be the coldest zone

28oc

of the room, as hot air rises, and the space above your head will

oc

16

be the warmest part of the room.

oc

oc

20oc

21

30

Radiators transfer heat into a room largely by convection from

a hot metal surface. Because the surface of the radiator is small,

16oc

oc

16

in comparison to the volume of the room, it needs a high heat

input and doesnt spread the heat evenly.
Convection currents circulate allergens, dust particles, fumes
and germs which are then distributed around the building,
contributing to an unhealthy atmosphere.

Underfloor heating
19oc

Underfloor heating systems are simple to install, low maintenance

20oc

20oc
19oc

19oc
oc

19oc

19

20oc

20oc

and cost-effective to run. The room is heated mostly by radiation,

the most natural and comfortable form of heating, creating an
even, comfortable environment with no hot or cold draughts.
Rooms with high ceilings such as churches, sports halls or
industrial units gain even greater benefits. With radiator systems,
some of the heat is immediately wasted as it rises to the ceiling.

24oc

24oc

With an underfloor heating system, the heat is concentrated at

floor level where it is most needed.
In rooms with large areas, underfloor heating is the only way to
heat the centre of the floor area effectively.

Floor surface temperatures

Floor coverings

Floor surface temperatures should not exceed certain levels

Floor coverings such as carpet, underlay and timber reduce the

otherwise discomfort and damage to the floor can occur.

floor heat output. Please check with us to confirm suitability.

The maximum recommended temperatures are: occupied areas,

Some floor coverings, especially timber and vinyl floors, have a

29C; peripheral areas, 35C; bathrooms, 33C.

recommended maximum floor surface or sub floor temperature

The floor surface temperature will vary according to the heat

output requirements of the room or building.

Tel: 01489 581787 www.warmafloor.co.uk

that they can operate at; if a higher temperature is used it can

damage the floor covering. Manufacturers data sheets should
be checked to confirm the coverings suitability.

Benefits of underfloor heating

Energy efficiency

Sustainability

Underfloor heating is the most energy efficient way of transferring

W
 armafloor has been part of the project team for many buildings

heat into a room and can consistently deliver substantial energy

savings compared to radiator systems.
Because underfloor heating systems benefit from the use of
lower water temperatures throughout the system (rather than hot
water in radiator systems), condensing boilers can generally run
at greater efficiency, saving even more energy costs.
By providing a constant heat, underfloor heating allows

that have won architectural and energy saving awards.

T
 he Warmafloor underfloor heating pipe, made from Polybutylene
(PB), is designed to last for the life of the building and is then fully
recyclable.
T
 he manufacture of Warmafloor PB pipe is less energy
consuming than the production of components for any alternative
heating system.

occupants to feel more comfortable at a lower temperature.

Interior design

Health & safety

Out of sight, underfloor heating gives a totally flexible layout, with

U
 nderfloor heating systems eliminate radiators (which can

no radiators to limit interior designs and furniture arrangement.

Underfloor heating is compatible with most types of floor
covering. The interior designer has more freedom to specify most

potentially be a health and safety risk because of their high

surface temperatures and sharp edges).
M
 oisture levels in floor coverings are reduced, which reduces

types of floor covering whether it be tiles, wood, laminates or

microbiological growth and the risk of slipping. In carpets it

carpets.

virtually eliminates dust mites.

Even though it cant be seen, underfloor heating adds perceived

value to the property.

A
 s there is no convection driven airflow, and the circulation of
bacteria and pollen is reduced, the indoor air quality is cleaner
and healthier.

Underfloor heating provides

the most comfortable all round
warmth of any heating system,
suitable for every type of building,
whether it is new build
construction or refurbishment.

Commercial, industrial and

public buildings

Bespoke designs
At Warmafloor we pioneered the use of full colour AutoCAD for
designing and preparing underfloor heating drawings which set the
industry standard.
In every project we generate four levels of drawings, starting at the
very conception of a project and finishing with record drawings.
These form part of the operation and maintenance manuals upon
completion of each project.
Our design process begins with a design meeting with the
consultant or design engineer. From this we will provide a zone
drawing indicating the manifold positions, floor sections and
number of circuits, as an initial design concept. We will then
estimate the total cost of the installation and draw up a bespoke
specification for the project.
As the project evolves it moves into the detailed planning stage.
We produce a full design for approval, incorporating all the details
which will be necessary to complete the installation.
Once that drawing has been considered and any modifications
made, we produce construction drawings which are issued to our
clients and, of course, to our fitters.
During the construction phase, if there are any changes on site,
our fitters amend the construction drawings. When the project is
complete, a set of record drawings are provided which accurately
reflect the underfloor heating installation.
Whilst this process may appear long-winded, we believe this
attention to detail at each stage is vital to the smooth running
of the site.

Tel: 01489 581787 www.warmafloor.co.uk

Energy source
Warmafloor underfloor heating
and cooling systems may
be powered by any boiler or
energy source.
For every installation we believe
that the specifier should
consider the most sustainable
energy source, both to reduce
energy costs and to minimise
environmental impact.
As a minimum, the specifier
should consider using a
condensing boiler. Other forms
of energy efficiency are now
commercially viable, which offer
significant cost reductions and
environmental benefits.

Biomass boilers consume wood pellets produced using the waste products of
commercial wood working processes.
Solar thermal systems may be used to provide a significant portion of the energy
requirement for domestic hot water and for underfloor central heating.
Air-to-water heat pumps are relatively low cost and simple to install, yet can convert
free heat from the outside atmosphere into useful low temperature warm water, which
is ideal for underfloor heating systems. Such heat pumps have an efficiency of 350% or
more, i.e. they can convert 1kW of electrical energy into 3.5kW of heating energy, even
when the outdoor temperature is as low as 0C.
Ground source heat pumps are more expensive to install, but deliver significantly greater
energy savings by taking free heating or cooling from the ground which is at a constant
temperature all year round.
Optimum solution
Generally, for the most efficient and most sustainable solution, we recommend a multivalent approach, where a combination of solar panels and air-to-water or ground source
heat pumps deliver most of the energy for most of the year, with a condensing gas boiler
being used for thermal top-up in times of peak demand.

Commercial, industrial and

public buildings

Our environmental credentials

Commercial,
industrial
and
We demonstrate ongoing leadership in eco-concern through our
Adhesives
public
buildings
own environmental
policy. Our centre and manufacturing facility
In our manufacturing operations we have attempted to minimise
at Fareham is proof that we do far more than merely reduce our

damage to the environment. Solvent based adhesives have, where

own carbon footprint. Through careful selection of materials and

possible, been replaced by hot-melt and water-based glues,

thoughtful operation on site, we have ensured that we minimise

to limit emissions. All new processes will be subject to a strict

our impact on the environment, whilst delivering some of the most

environmental examination.

sustainable heating and cost-effective systems.

Our environmental credentials

Packaging

When packing we limit the environmental impact by keeping label

size to a minimum and by wrapping packs in lightweight stretch
wrap film. All boxes used in our packaging are made from

of our
We encourage
thetouse
of
recycled cardboard.
We endeavour
use biodegradable

clipping s
The s ystems Cli
ulation throughout in
packaging ins
throughout.
Tacker staples ar
accordance with Part L .
Clipping systems
from reworked P
Adhes
ives
We also use
reworked
material in the production of our clipping
part of our comm
systems. The staples used in the Cliprail and Tacker systems are
In our manufacturing
eco-friendly manu
all made from reworked PVC as part of our commitment to
operations we have
When the s ystem
eco-friendly manufacturing. When the system reaches the end of
attempted to minimise
the energy.
end of its use
its useful life, it can be recycled to reduce waste and save
damage to the
can be recycled
Manifolds environment. Solvent
material us ed ag
Our manifolds are manufactured from composite materials
reduce waste an
based adhesives have,
selected for their specific function in the manifold. We assemble
energy.
where possible, been
all components for our manifolds at our Head Office warehouse in
replaced by hot melt and
Manifolds
the UK.
water- based glues, to limit
Our manifolds ar
On site waste
emissions. All new
manufactured
fro
The products
and materials
used
our installations are
selected
processes
will
beonsubject
and
re
so they cantobearecycled
can therefore be removed
fromare
site totally
in
strict and
environmental
the normal way and dealt with in the appropriate manner.
We assemble all
examination.
Pipewor k
We demonstrate ongoing
components for o
WarmafloorPackaging
is an environmentally committed organisation
leadership
Pipework in eco- concern
Our pipework is
manifolds at our
dedicated to world welfare and the best future for our children.
Our pipework
is manufactured in accordance with the standards
through
our own
manufactured in accordance
warehouse in the
When packing we
laid out in the Environmental
and Performance Characteristics of
environmental
policy. Our
with the standards laid out
have tried to limit the
On Site Waste
Polybutylene Pipe document (C1/SFB 53/In6) June 2005.
centre
and manufacturing
in the 'Environmental and
environmental impact by
facility
at Fareham is proof
The products an
Performance Characteristics
Insulation
keeping label size to a
materials us ed o
has more
for manythan
years selected
products Pipe'
that
ofinsulation
Polybutylene
thatWarmafloor
we do far
minimum and by wrapping
have
an
Ozone
Depleting
Potential
(ODP)
and
Global
Warming
installations are
document.
merely reduce our own
packs in lightweight
Potential (GWP) of zero. Our expanded polystyrene (EPS) is
s o they can be re
carbon footprint.
stretch wrap film. All
Ins ulation
manufactured using pentane which contains no CFCs , HFCs
and can therefor
boxes used in our
Through
careful
s election
or HCFCs
. We encourage
the use of insulation
throughout
Warmafloor
hasin for many
removed from s i
packaging are made from
accordance
with
Part
L.
of
the
building
regulations.
of materials and
years s elected insulation
normal way and
recycled cardboard. We
thoughtful operation on
products that have an
in the appropriat
endeavour to us e
Ozone Depleting Potential
site, we have ens ured that
Warmafloor is an
biodegradable packaging
10
Tel: 01489 581787 www.warmafloor.co.uk
(ODP) of zero.
we minimis e our impact

Our sustainability mission

We believe every individual
and organisation should take
responsibility for sustainability
in their buildings in
construction, in the on-going
use of building services, and in
creating an attractive
environment.
At Warmafloor, we have
planned our own office and
warehouse facilities to deliver
optimum sustainability by an
intelligent combination
of 12 simple and cost-effective
elements. It requires only
20% of the operating energy
consumed by a similar sized
conventional building.

Low energy underfloor

Lighting. Maximum use of

11 Carbon offset. Well

natural daylight, plus low

designed planting of

chilled ceiling.

high efficiency boiler

energy lighting controlled

trees around the car park

provides thermal top-up

by PIR sensors (which

perimeter provides carbon

for underfloor heating and

automatically turn lights off

offset for the energy that

District Hot Water (DHW),

when a room is not in use),

the building uses.

when required.

minimise lighting costs.

Thermal mass. Substantial

buildings floors and core
act as a thermal store
to minimise day/night

temperature swings.
Ground source heat
pump. Coils of water filled plastic pipe, laid in
trenches beneath the
car park, provide a year
- round source of free

Solar hot water. Solar

collector panels on the
building provide up to
100% of hot water needs
in the summer months
and up to 25% of hot
water heating energy even
during dull winter days.

Building envelope.

wind turbine generates

Insulated cladding panels

simple building energy

more than enough

and reflective glass

management system

electricity to match the

minimise heat loss or

ensures all the various

buildings needs and

gain through the building

energy-demanding

allows for excess capacity

envelope. Specially

elements operate in

to be sold back to the

planted Silver Birch trees

harmony, to reduce

National Grid. (At the

provide solar screening

energy demand.

time of going to press

maximum light in winter.

7

12 Wind turbine. A simple

Integrated control. A

during summer, yet allow

energy.
4

boiler. A relatively small,

volumes of concrete in the

Gas fired condensing

heating and cooling, and

10 Rainwater harvesting.
Underground rainwater

Ventilation. Natural

storage tanks provide

ventilation through

water for vehicle cleaning

an air handling unit with

and gardening.

installation of our wind

turbine is delayed. We
are awaiting planning
permission by the local
authority).

efficient heat exchanger

and high efficiency filter,
ensures air quantity and
increases employee
productivity.

11

Commercial, industrial and

public buildings

Airbus factory
Warmafloor designed and
installed the underfloor heating
system for the Airbus A380
wing assembly factory in 2004.
Some 60,000 metres of 20mm
polybutylene pipework was
installed directly into the
structural slab of the building.
More recently, Warmafloor were
awarded the contract for the
latest wing factory for the new
A350 Airbus airliner. Cost has
always been a key element in
securing major contracts.
Another key element was
Warmafloors ability to deliver
the project in a record 2 week
programme, along with a 50%
energy saving.

British Museum
A prestigious project in The
Great Court at The British
Museum specified a
Warmafloor heating/cooling
system throughout the main
public areas, covering
4,000 sq metres.
A castellated panel system was
installed. It provides a steady
state environment by switching
from heating, to cooling served
by chilled water from the central
plant room.

12

Tel: 01489 581787 www.warmafloor.co.uk

Sports academy
A custom built, state of the art
sports complex for the
University of East Anglia.
The facility was the largest of its
kind in the UK. The pool,
surrounding seating areas and
changing rooms feature a
Warmafloor underfloor heating
system; providing warmth
underfoot and quick-drying
surfaces that reduce the
possibility of bacteria growth.

Crown Lane
School, London
Warmafloor delivered the
complete underfloor package;
including design, supply and
installation at Crown Lane
Primary School, South
West London.
This complex shaped building
comprises a new 420 place
primary school and a 25
place nursery.
The site also has a floodlit
games court and various
external play areas.

13

Commercial, industrial and

public buildings

Aspire Defence contracts

Warmafloor are designing and installing underfloor heating

It was clear that only Warmafloor offered the practical, capable

systems for Aspire Defence, who are delivering the MoDs

and financial performance needed for such a large scale ongoing

largest infrastructure project, Allenby/Connaught. The project is

project. We are one of the only specialist heating contractors with

providing fully serviced new and refurbished living and working

a large enough team of designers, engineers and installers and

accommodation; training, leisure and storage facilities for nearly

with the expertise to deliver such a major scheme in a cost-

19,000 military personnel across four Army Garrisons at Aldershot

effective manner.

and on the Salisbury Plain. The work is believed to include the

largest underfloor heating project ever awarded anywhere in
the world.

Warmafloor were able to effectively work across multiple

mechanical and electrical contracts, providing a total underfloor
heating system design from concept to completion.

The underfloor heating systems are being installed in various

building types; such as stores, secure units, technical buildings,
office accommodation and leisure facilities. Five years after it
started, the project is positively affecting the lives of nearly 20 per
cent of the trained soldiers in the British Army.
Whilst some early designs for the project utilised conventional
radiator systems, it was quickly realised that, for this project, they
would not provide the best option and a specialist contractor was
required to install a system capable of providing long term
energy savings.

Triple Mess,
Bulford

Community Centre,
Warminster

Recreational Training
Centre, Tidworth

Aldershot Garrison

Bulford Garrison,
Accommodation

Junior Rating Diner,

Warminster

Images credited to: Project Allenby/Connaught

16

Tel: 01489 581787 www.warmafloor.co.uk

Solid floor screeded systems

Tacker system
Warmafloor systems can be

The Warmafloor Tacker system

fitted to any type of concrete

is the most widely used for

floor construction which has a

screeded floors because

screed topping.

of its versatility and ease of

installation.

The elements of the system;

floor insulation, edge insulation,

Warmafloor Tacker floor

moisture barrier, fixing system

insulation panels are available

and pipework are installed

in any thickness and various

utilising one of the Warmafloor

insulation materials, providing

systems as detailed, then

solutions for any floor

covered with the appropriate

requirement.

screed and final floor finish.

The floor insulation panels,
The system can be selected

whilst generally supplied in

according to constructional

expanded polystyrene EPS, are also available in

requirements and we will specify

polyisocyanurate (PIR) (eg Celotex) or in extruded

what we consider the most

polystyrene, providing extra strength or greater

appropriate for the project.

U values.

We will also advise on the most

Warmafloor Tacker floor insulation panels have a

suitable depth and screed

hessian-based polyethylene foil laminated to the

type to be used. Warmafloor

surface of the panel. The foil provides a gridded

screeded systems are available

reference for correct pipe spacing and fixing and

to suit all types of commercial,

is also water resistant.

Tacker System

industrial, public sector and

housing applications.

Edge insulation is laid around the area to be

heated; this provides a barrier against perimeter

Once installation is complete

heat loss and for screed expansion. The

and the screed installed and

Warmafloor Tacker insulation panels are then

dried out to suitable moisture

laid over the complete floor area. Warmafloor PB

content, almost any kind of floor

pipework is then laid out in circuits and secured

covering (including marble, tile,

into the Tacker panel by specially designed

carpet, stone and timber) can

staples, installed with a Tacker gun. These staples

be fitted to the floor surface.

are fully retained by the fabric thereby preventing

the pipe lifting during screeding. The underfloor
pipework is connected to the Warmafloor
manifold, filled with water, and pressurised to
check for watertightness.
As soon as practical after the installation is
completed, the screed should be laid over the
system to the required depth.

17

Commercial, industrial and

public buildings

Solid floor screeded systems (continued)

Wire Grid system
The Warmafloor Wire Grid system is a simple to install approach
that provides a robust fixing system where Warmafloor Tacker floor
insulation panels are not used.
The floor is fitted with suitable floor insulation, overlaid with a
vapour barrier, with edge insulation to all walls in preparation for the
installation. An A142 wire grid, which has a 200mm square mesh
pattern, is laid butt jointed onto the floor insulation.
Warmafloor PB pipework is then laid out on the grid in the required
configuration and secured to the grid with plastic securing ties.
The pipework is circulated back to the manifold and is pressure

Wire Grid System

tested, before screed laying is carried out.

The Warmafloor Wire Grid system is suitable for sand/cement
or concrete screed coverings but is not suitable for liquid
screed applications.

Warmafloor Clip Rail system

The Warmafloor Clip Rail system comprises plastic pipe-locating
rails, fitted to the floor insulation, into which Warmafloor PB
pipework is clipped.
The rails are available for both 16mm and 20mm pipe.
Edge insulation and floor insulation is overlaid with a plastic
moisture barrier to cover the floor area. The Warmafloor Clip Rails
are then located according to the system design and secured into
the floor insulation with fixing pins.
Once the Clip Rails are fixed, Warmafloor PB pipework is laid out in
the required system configuration for the building and is connected

Clip Rail System

to the manifold.
The underfloor system is then filled with water and pressure tested
to confirm the systems integrity prior to the floor screed being laid.

18

Tel: 01489 581787 www.warmafloor.co.uk

System Plate panels

Screed: Sand and cement with

fibres 65-75mm
Liquid screed 55mm

Warmafloor system plates are interlocking vacuum formed sheets

of recycled plastic which incorporate pipe-locating castles. Sheets

Floor finish: tiles,

carpet, wood etc.

are laid over the sub floor, thermally insulated in accordance

with Building Regulations, overlapping the edges by 75mm and
interlocking them to form a continuous layer.
Warmafloor 16mm PB pipework is clipped into the panels and the
installation is complete.
The system panels are better than pocketed systems as the
screed can surround the pipe providing a greater output.

8mm
Foam edge
insulation
insulation
System plate
Concrete sub floor

Warmafloor UFH pipe

System Plate Panels

Note: System plates are useful where there

is a restricted floor depth.

19

Commercial, industrial and

public buildings

Structural concrete floor systems

Warmafloor systems can be incorporated within load bearing
structural floors, in a variety of applications, from factories and
warehouses to sports complexes.
There are generally two types of floor construction, those of a
simple concrete slab construction and those which incorporate
a reinforcing wire mesh grid at mid level in the floor. The floor
construction generally comprises a compacted and level hardcore
bed, which is sand blinded flat. Onto this, suitable insulation panels
of the required density and thickness are laid and covered with
vapour barrier, with edge insulation to the perimeter of the building.
Wire mesh is then installed either on the floor insulation in the
case of simple concrete slab floors or in the case of structural
floors, at the required level in the slab.

Concrete Slab Floor Wire

Mesh System

The Warmafloor PB pipework is secured to the mesh with pipe ties

in the required configuration and spacing.
The Warmafloor PB pipework is circuited to the Warmafloor
manifolds, filled with water and tested. Concrete is then laid to the
required depth and strength, dependent upon the design criteria of
the slab.
Floor finishes both with screeded concrete and structural floors
can include tile, wood, paving slabs, marble etc.

Structural Floor With Reinforcing

Mesh System

20

Tel: 01489 581787 www.warmafloor.co.uk

Floor expansion/movement joints

Heated screed or concrete floors will expand and contract slightly
during use; the edge insulation is normally sufficient to take up this
movement. However, in certain situations and especially with floor
finishes such as tile, marble or stone, screed expansion joints will
be required. Whilst the Warmafloor pipe characteristics enable it to
be stretched by 50% plus without damage, pipes passing through
joints should be sleeved for safety.

Screeded floors
Very large rooms or areas may need to be sub-divided by
expansion joints or crack inducers, which can then be sealed after

Expansion Joint - Screeded Floor

screeding with flexible filler. Where these joints occur, the pipework
circuits crossing them should be kept to a minimum and where
pipes do cross the joints, they should be sleeved as detailed. In
addition to this, screed expansion joints will be required in larger
floors finished with tile, marble or stone to suit the floor layers
requirements.

Structural floors
Occasionally the underfloor heating pipework may have to run
across movement joints in a structural floor slab. Where this
occurs, provision has to be made for movement in the screed
and floor finish above. Whilst crossing movement joints with
piping should be avoided if possible, where they do cross over,
a pipe sleeve of a minimum of 600mm long must be fitted to
allow sufficient movement. For specific advice on movement
requirements, always refer to the screeding contractor or architect.

Movement Joint In Structural Floor

21

Commercial, industrial and

public buildings

Batten/Sprung floor systems

Warmafloor has a number of systems to suit different
applications of batten and sprung floors.
These can be split into four categories:
Systems for use over heated screeds
Systems for fitting over concrete or timber floors
Systems for fitting over engineered timber floors
Systems for fitting over concrete floors with adjustable
height battens

Batten Floor - On Heated Screed System

Batten floor on heated screeds

Batten floors can easily be installed over floors which have a
Warmafloor heating system already embedded in the floor screed
itself. This screed provides a level floor, so that the battened floor
system can easily be installed on top of the heated screed without
further builders work being required. This system is now widely
used, particularly in sports and assembly halls and can be used
with batten depths up to 50mm. The heated screed provides a very
uniform heat to the timber floor, avoiding peaks of temperature that
can occur with other methods fitted between battens.

Over concrete or timber deck

Batten Floor System

In this application suitable floor insulation is laid between the floor

battens and the underfloor pipework is installed using a Clip Rail
fixing, or secured into the insulation using Tacker pipe clips.

22

Tel: 01489 581787 www.warmafloor.co.uk

Batten Diffusion Plate system

In the case of sports halls and similar applications, battened floors
are sometimes installed. Where adjustable height floor battens
are used, this provides a variable floor void of 50 - 100mm. In
these situations a Warmafloor Diffusion Plate system is required
if the standard applications are not suitable. Rigid floor insulation
should be installed between battens by the flooring contractor to
the required depth and Warmafloor metal diffusion plates with inset
pipe grooves installed to the floor battens. After installation of the
diffusion plates, Warmafloor PB pipework is slotted into the pipe
grooves in the plates and circuited back to the manifold. Flooring
is then installed over the completed system. Where this system is
used on ground floors, the thermal value of the insulation used must
meet the requirements of Part L of the building regulations.

Batten Diffusion Plate System

Acoustic floors to Part E Regulations

If the flooring is being installed to the Sound Transmission in the
Building Regulations Part E, floor battens are fitted with acoustic
foam strips or cradles, often with acoustic mineral wool insulation
below the floor. When installed in acoustic floors the underfloor
system construction will need to be confirmed for each individual
application.

Acoustic Batten Flooring System

23

Commercial, industrial and

public buildings

Floating Floor system

The Warmafloor Floating Floor system is for use when underfloor
heating is to be installed on concrete floors where a dry finish to
the floor is required, not a screed topping.
The maximum heat output of 75 W/m2 is less than for a screeded
floor system, so the Floating Floor system is predominantly for use in
new buildings, where the heat requirements of the building are less.
This system relies on the floor being flat and level.
The Floating Floor system involves pre-grooved polystyrene floor
insulation panels, fitted with pre-grooved metal diffusion plates into
which the underfloor pipework is fitted.
The installation involves laying the Floating Floor panels to cover
the complete floor area.

Floating Floor Panel

At door openings, floor support battens will need to be fitted as in

a normal Floating Floor. Warmafloor PB pipe is then clipped into the
diffusion plates, circuited to design requirements and run back to

Panels available in:

25mm, 35mm, 50mm and 75mm thick

the manifold.
Finally the flooring is laid on the system chipboard, plywood or
dry screeding flooring panels such as Fermacell and then the final
floor covering is laid.
Warmafloors Floating Floor system offers complete access to the
installation for any component repair or replacement, by lifting
the flooring.

24

Tel: 01489 581787 www.warmafloor.co.uk

Suspended Floor systems

There are generally two types of suspended timber floors:
standard timber joists and engineered timber joists.
Warmafloor can provide a system for both applications.

Standard joists
Supporting battens are fitted between joists upon which rigid
insulation is installed. Pipework is installed on the insulation and
circuited via joist notching, back to the manifold.
Should the joists be interspaced with steel beams or other

Standard Joist Floor System

obstacles, it is recommended to over-batten the joists. This

provides a clear space in which the underfloor circuits can run
without joist notching or other structural clashes. Rigid floor
insulation is installed as normal between the joists and the
Warmafloor underfloor system is fitted easily within the batten
height. The flooring is then finally fitted.
For ground floor applications the insulation between joists must be
compliant to Part L of the Building Regulations and the insulation
must be tightly fitted, to stop any air ingress from below. On upper
floors 25mm Celotex or similar insulation should be used.

Standard
StandardJoist
JoistSystem
System- -Over
OverBatten
BattenDetail
Detail

Engineered joists
With Engineered joist systems the joists should be decked out with
a sub-deck. Batten positions are marked out on the sub-deck,
then Warmafloor pipework is laid out and pinned to the sub-deck.
Floor battens are fitted and then the final chipboard or plywood
flooring is laid to provide a complete installation. Insulation should
be installed between the joists. This type of floor is generally only
used on upper floor levels.

Engineered Joist Floor System

25

Commercial, industrial and

public buildings

Raised Access Floor system

The Warmafloor Raised Access Floor (RAF) system provides
warm water underfloor heating/cooling into standard Raised
Access Floor. The system can be used with many Kingspan
and Propaflor RAF systems.
The RAF floor pedestals are installed and the special
Warmafloor RAF brackets are attached to the pedestals.
Warmafloor 35mm thick, 1.2m long heating modules are then
quickly and simply clipped into the brackets.
Once these are all fitted, continuous lengths of Warmafloor
16mm underfloor heating pipework is inserted into the
Warmafloor Raised Access Floor modules, connecting to

Raised Access Floor System

underfloor manifolds as necessary. Floor panels are then laid

as normal.

Cross section through floor

Heating - The Warmafloor RAF system can provide radiant heating
from 50 - 60 W/m2 at a flow temperature of 45 - 60C.
Cooling Using a flow temperature of 13C the system can

Section through floor

provide up to 25 W/m2 from the floor surface. If used in

conjunction with plenum ventilation and standard grilled floor
panels, this can be increased to 35 - 40 W/m2.

200mm

400mm

35mm foil faced

polystyrene panels
1.2m long
200mm

100mm

The Warmafloor Raised Access Floor System makes it possible to

install heating/cooling within raised floors, providing a way for large,
open plan offices to be heated evenly and comfortably. Areas can
be zoned and independently controlled in multiple offices. Should
layouts change, the heating modules can be repositioned as
required providing a very flexible system.

System benefits
A very cost-effective solution compared with other alternatives.
Fast efficient installation.
Heating modules provide good access to floor void.
Can be retro-fitted to suitable floors.
The system is future proof, as it can be dismounted and
repositioned.

26

Tel: 01489 581787 www.warmafloor.co.uk

Warmafloor Insulation
Floor tiles
Raised Access
16mm PB support clip
(by Warmafloor) Floor support
Pipework (by Warmafloor)
(by Warmafloor)

Patent No: GB-2375 815 B

Bespoke systems
Warmafloor underfloor heating solutions are bespoke; designed to

This surging demand for bespoke systems enables our designers

meet each projects specifications. They are also ideally suited for

to push the boundaries of underfloor heating technology for the

use in a growing range of non-standard projects and applications.

benefit of future users.

The increasing popularity of underfloor heating solutions in

With our proven standard design process and our already

traditional applications such as residential and commercial

extensive wealth of expertise in underfloor heating, we are able to

buildings reflects widening acceptance of the real comfort and

adapt basic principles and standard component configurations to

efficiency benefits that these systems offer. They also permit

provide long lasting effective solutions.

greater flexibility of design, giving architects and interior designers

more freedom of expression.

Warmafloor underfloor heating systems can be incorporated into

buildings of all types and sizes in a virtually unlimited range of

As a result, architects and specifiers are also turning to Warmafloor

possible applications.

solutions to provide the same benefits for the developers and

occupants of all types of buildings. In addition, they are combining
our heating solutions with innovative construction detailing, such as
incorporation in access flooring or sports halls.

Bespoke solution within

structural ceiling at Gloscat
(Gloucester College of Arts
and Technology).

A unique and specific solution

for in-situ cast slab as used in
SGI Brighton.

A unique sports floor

underfloor heating solution
is used in four West Kent
colleges.

Special heating solution built

into the walls at the RSPCA
Kennels in Bath.

27

Residential buildings

Nursing homes
Warmafloor were strongly involved in a concept to provide 10 care
centres in close collaboration with Hampshire County Council.
The brief was to provide a bespoke design for each project, to
ensure the most effective and environmentally efficient heating
system; giving maximum comfort conditions to Hampshires ageing
population.
The initiative was developed in partnership with the County Council
and Hampshire and Isle of Wight Strategic Health Authority, at a
cost of around 60 million.
The nursing homes were built on 15 sites spread across the county
to best serve Hampshires elderly residents. The ground breaking
60 million project initiative called Enhance was thought to be the
first of its kind in the country.

Care apartments
Milton Village Extra Care facility in Portsmouth was constructed in a
timber frame using a screed floor finish incorporating underfloor
heating. This was only achievable by using a liquid screed with a
shallow depth of 55mm, (much less than standard sand/cement
floor finishes of 75mm), allowing for a more lightweight
construction. Separate underfloor heating zones were created for
each bedroom unit and were arranged to allow independent control,
taking into account different temperature and timing requirements
for different areas.

28

Tel: 01489 581787 www.warmafloor.co.uk

Ledborough Gate
A distinctive Charles Church
housing development of 31
individual homes is designed to
the highest specifications.
Each property has a Warmafloor
underfloor heating system
installed to provide luxurious
comfort and warmth throughout.
Out of sight underfloor heating,
also allows a totally flexible room
layout, without radiators to limit
sophisticated interior designs.
The client wanted total internal
flexibility and luxurious warmth,
a mixture of floor finishes, and a
totally silent operation.

Wembley
Apartments
A high density and mixed use
block comprising 286
residential apartments forming
part of the citys regeneration.
This sustainable approach to
high rise development
incorporates Warmafloor
underfloor heating in each of
the residential units.

29

Residential buildings

Solid floor system

Tacker System

System Plate Panels

Screed: Sand and cement with

fibres 65-75mm
Liquid screed 55mm

Floor finish: tiles,

carpet, wood etc.

8mm
Foam edge
insulation
insulation
System plate
Concrete sub floor

Warmafloor UFH pipe

Solid floor screeded system

Many house buyers now appreciate the benefits of underfloor
heating and see it as a premium feature when choosing a
new home.
Many new developments today use screeded concrete floor
systems, which are ideal for incorporating an underfloor heating

Warmafloor offers several types of solid floor heating system

those optimised for use with screeded floors, and those designed
for applications where the heating can be cast into the structural
concrete floor element.

system as part of the fabric of the building.

Clip Rail System

On the screeded systems, a choice of fixing methods including

Electric Millimat and controls can be provided on a supply only

Tacker insulation panels, Castellated modular panels, flexible Wire

bases for tilers, builders or D.I.Y. installation.

Grid and Clip Rail systems ensures that the right solution can be
found for any application.
Solid floor systems can be combined with almost any kind of floor
finish allowing specification flexibility in standard designs.

30

Electric Millimat
Millimat System
Electric

Tel: 01489 581787 www.warmafloor.co.uk

Floating and suspended floor systems

Standard Joisted Floor System

Engineered Joist System - Over Batten Detail

With floating and suspended

Joisted floors in domestic

finished with a layer of timber

positioned between the joists

floor systems the heating

applications are generally

flooring strips or chipboard

and held in place with battens.

system does not need to be

found in first or second floor

as required.

incorporated into the fabric of

applications. A solution can

the building. As it is a dry trade

be found to provide a system

installation, there is no need to

appropriate to most types

wait until a screed has dried

of joist system. The floor is

before fit-out can continue.

For example, where timber

This is a straightforward system

to install, offering lasting benefits.

suspended floors are specified,

the Warmafloor insulated
elements can simply be

Pre-grooved insulation boards incorporating aluminium diffusion

plates which are suitable for concrete slab, screeded and below
chipboard floors, where a dry floor finish is required. The insulation
panels are machined from high performance extruded polystyrene
with a high compressive strength of 200kN/m.
The low thermal mass allows faster response times when
compared with screeded floors.

Floating Floor Panel

31

Components

Polybutylene pipe
Pipe usage
Warmafloor uses Polybutylene barrier pipe to circulate warming

POLYBUTYLENE

or cooling water through the floor (or wall or ceiling). The EVOH
EVOH - Oxygen
Barrier Layer

(ethanol vinyl alcohol) barrier layer is embedded within the pipe

wall, using a 5 layer co-extrusion process to ensure that oxygen
cannot permeate through the pipe wall over time, to enter the
water circuit.
The introduction of oxygen into the system could potentially
contribute to corrosion in the boiler or metal pipework in the
rest of the system.

Performance
Polybutylene has an unrivalled balance of properties to satisfy the

ADHESIVE - Ensures
secure bonding of
polybutylene to
barrier layer

POLYBUTYLENE

demands of the hot and cold pressurised water pipe market. The
main aspects which distinguish it from other candidate materials
are its flexibility and superior resistance to stress over long periods
of time at high temperatures.
Flexibility is a key factor because it eases installation across
a broad range of internal temperature conditions. The relative

Material Properties

flexibility of different plastics is indicated by the table (right) showing

typical flexural elasticity values for different polyolefin pipe materials.

Physical Properties
Density

Polybutylene is non-corrosive, resists frost damage, and is

Mechanical Properties
Wall Roughness

unaffected by hard, soft or aggressive water conditions. It is

Tensile Strength at Yield

creep-resistant and offers high impact strength meaning that if it is

distorted on site, it will return to original shape.

Guarantee

Unit

Performance

g/cm3

0.937

mm

0.007

ISO R 527

MPa

18

Tensile Strength at Break

ISO R 528

MPa

40

Elongation at Break

ISO 1183

ISO R 529

350%

Flexural Elastic Modulus

ISO 178

MPa

350

Notched Impact Strength at

20oC

ISO 180

kJ/m2

65

Notched Impact Strength at

0oC

ISO 180

kJ/m2

25

Warmafloor Polybutylene pipe is designed to last for the life of the

Thermal Properties
Melting Point Range

building and is guaranteed for 100 years. This guarantee period is

Vicat Softening Temperature

DSC(a)

124 - 126

ISO 306

oC

116

longer than other credible warranties being offered.

Co-efficient of Linear
Thermal Expansion

ASTM D696

1.3x10-4

The pipe is manufactured to, and performs to, all known European

Thermal Conductivity (20oC)

ASTM C177

0.19

quality and performance standards, including:

Specific Characteristics

BS EN 9001:2008

Wet Abrasion
(sand slurry test, 23oC, 100h)

BS EN ISO 21003 BSI Kitemarked

32

Methos

Tel: 01489 581787 www.warmafloor.co.uk

Environmental
manufacturing

Recycling and
re-use

Polybutylene is produced

Recycling of Polybutylene is

from crude oil by refining and

possible because the molecular

polymerisation the polymer is

structure of the material is

extruded to create the finished

not altered by the production

Non-corrosive

product. Polybutylene has

process. Any clean production

Resistant to frost damage

markedly less embodied energy

waste during the manufacturing

Inert to water hardness/softness

than almost all competing

process is reworked and added

materials by virtue of the ease

back to the production process

with which raw materials

in accordance with ISO 15876

Pipework does not encourage micro-biological growth

can be transported and the

and BS 7291.

High impact strength

Polybutylene pipe used in

Creep resistant

The manufacturing of

underfloor heating applications

Fully protected internal barrier

Polybutylene pipe has

will almost always out-live the

Low energy consumption in manufacture

significantly less environmental

building. Pipe is installed within

impact in terms of energy

the fabric of the building in

usage and emissions, than is

unjointed pipe-runs. Where

Low environmental impact in terms of soil, water and air pollution

the case for metal pipe systems

Polybutylene pipe is damaged,

Physiologically safe will not taint water

and other plastic pipes.

eg by building refurbishment,

Minimal internal resistance reducing hydraulic pumping head

manufacturing process.

Finally, because Warmafloor

uses UK manufactured pipe
there is minimum environmental
impact in transporting the
finished product to site.

it may be repaired by a simple

push fit repair connector,

Features and Benefits of Polybutylene

Standard and barrier pipes available
High flexibility even at very low temperatures
Resistant to stress

Unaffected by chemical inhibitors

Produced in compliance with ISO 14001

Safe installation procedures no requirement for pre-tempering of pipe

which maintains the molecular

Pipes can be fusion welded, if required

integrity and all the performance

No flame, specialist tools or chemicals required during installation

characteristics of the

therefore no risk to installers

undamaged pipe.

100 year warranty

Readily recycled
Recycled material has same recoverable heat energy as heating oil
Does not produce toxic or corrosive gases when burned
Proven in installations since the 1970s and on many high profile
construction projects
Suitable for heating and cooling applications
No intrinsic resale value
Multitude of coil lengths for economical installation with minimal waste
Size and type of coil specifically engineered for embedded
coil technology
UK manufacture, reducing whole life cost including transportation

33

Components

Underfloor manifolds and actuators

Standard Modular and
Blending Manifolds

Composite Manifold

Warmafloor Standard modular manifolds are used where the water

supply temperature to the manifold is provided at the correct
temperature and flow rate for the underfloor system.
Warmafloor Blending manifolds are for use where the LPHW
supply to the manifold is at a higher temperature than required for
the underfloor system.
Standard manifold dimensions
Circuits

Manifold width
(mm)

10

11

12

Our composite manifolds utilise the most appropriate materials

for the specific function they are intended. Therefore the body
of the barrels is manufactured from Glass Fibre Reinforced Black
Polyamide (GRBP). The material is not adversely affected by
accidental contact with linseed oil sealing compounds and will be
unaffected by soft, hard or aggressive water or inhibitors.
The circuit flow rate adjusters and indicators are manufactured
in ABS known, for its wide use in plumbing materials and its
operating temperature range.
Gauges are industry standard giving reliable and accurate readings.

330 380 430 480 530 580 630 680 730 780 830

Manifold Height 440mm - Depth 120mm

Fitting clearance - manifold width 100mm, height 250mm, depth 175mm
manifolds should be fixed at a height of 300mm from finished floor to bottom of
manifold. Access is required to front of the manifold for maintenance purposes.

Electric actuator 24v or 240v

These are available for automatic circuit control via
a room thermostat or sensor
Voltage
Power consumption
Running current (max)
Maximum current
Time to fully open

240v AC
2w
300mA
0.15 amp
4 minutes

Power ON
Power OFF

Circuit Open
Circuit Shut

24v AC/DC
2w
250mA
0.25 amp
3 minutes

Sealing rings are manufactured from EPDM rubber. Again this is

used for long term secure durability.
Industry standard brassware is used for compression connections
for both 16mm and 20mm polybutylene pipe, drain cocks, AAV,
blending valve assembly and pump connections.
High grade stainless steel ball valves are used to isolate/shut-off
the manifold.

10

1. Flow rate adjuster/indicator

2. Wall mounting bracket
3. Manual head
4. Thermoelectric actuator head
5. Pipe connectors 16-20mm
6. Combined pressure & temperature gauge
7. Fill/drain valve
8. Isolating valve
9. Automatic air vent
10. Flow temperature gauge

3
4

6
7

34

Tel: 01489 581787 www.warmafloor.co.uk

Special stainless steel brackets are used to secure the manifold and
offset the barrels to allow the flow pipework to be routed behind and
adjacent to the return connection.
Warmafloor use a Grundfos Alpha standard 25/60 pump with a 3
speed setting with a EPC B rating.
Warmafloor also provide the composite Blending manifold with a
Grundfos Alpha 2 inverter drive 15/50 pump with an EPC A rating.
This provides superior energy/system performance if required.
The Blending manifold set utilises a full bypass valve which is
unique in that it can be used in both heating and cooling mode. The
advantage of this is that it can be used with heat pumps and future/
alternative energy sources.
The standard manifold also provides this capability.
Blending manifold dimensions
Circuits
Manifold width
(mm)

10

11

470 520 570 620 670 720 770 820 870 920 970

Manifold Height 490mm - Depth 130mm

Fitting clearance - manifold width 100mm, height 250mm, depth 215mm
manifolds should be fixed at a height of 300mm from finished floor to bottom of
manifold. Access is required to front of the manifold for maintenance purposes.

Thermostatic control head settings

Screeded floor

Timber floors

12

Temperature oC
10
20
30
40
Temperature oC
50
60

Position
1
2
3
4
Position
5
6

Both types of manifold now have 1 single side flow and return
primary connections which can be handed to satisfy specific
requirements. This also enables primary pipework to be routed
horizontally or vertically, to one point of connection.
The ports on the barrels are threaded and lock in position in both
vertical planes allowing for a 180 degree rotation. This allows
Warmafloor to serve circuits both above and below from one
manifold.
The sealed actuator units also allow safe operation when ports are
serving circuits above the manifold.
All configurations of the manifold have been tested rigorously by the
British Board of Agreement (BBA CERT.10-4738). This has resulted
in the BBA certifying the manifold to a minimum life expectancy of 25
years under normal operating parameters. Typically this is a maximum
temperature of 70C and a minimum of 4C. The maximum working
pressure is 4 bar and maximum test pressure is 8 bar. Maximum
primary flow rate for a standard composite manifold is 60 litres per
minute whilst the Blending manifold is 30 litres per minute.
The manifold is a modular manifold made up with single or 3 port
pieces for maximum flexibility. A 12 port manifold is the maximum
size. (sizes/dimensions are given in the table).
The manifold incorporates a simple lift balance cap and memory ring
which facilitates easy flow rate calibration.

13

12

1. Flow rate adjuster/indicator

2. Wall mounting bracket
3. Manual head
11
4. Thermoelectric actuator head
5. Pipe connectors 16-20mm
6. Combined pressure & temperature gauge
7. Fill/drain valve
8. Isolating valve
9. Thermostatic control head
10
10. Circulating pump
11. Flow water temperature sensor
12. Automatic air vent
13. Flow temperature gauge

3
4

9
5

6
7
8

35

Components

Screeds over underfloor heating

Except for buildings where the concrete slab is left exposed, (such
as a warehouse), all concrete floors are covered with a screed
layer, which provides a final level finish, onto which is installed the
floor covering; tiles, carpet, wood etc.
When underfloor heating is installed, perimeter wall insulation and
floor insulation panels with a fitted moisture barrier are installed on
the floor slab and the underfloor pipework secured to the panels.
This is then covered with the final screed layer.
The screed has to be of suitable depth both for strength and to
provide sufficient cover over the underfloor heating pipework to
avoid the screed cracking. When installed over floor insulation the
screed is called a floating screed.
There are four main types of screed that are used:
Sand and Cement (with added fibres)
Sand and cement screeds are a mixture of sand and cement
generally in a 4 to 1 ratio mixed with water. Sand and cement
screeds are either mixed on site or can be obtained ready mixed
from the plant. We recommend the use of added fibres which
reduce micro cracking to the screed surface.
Sand and Cement Enhanced Screeds
Enhanced screeds are sand and cement screeds with added
chemicals that improve the properties of the standard screed.
The improved properties included faster drying times and/or extra
strength. The additives are made by various manufacturers and are
sold under their own trade name, eg Flexidry F1. The screeds can
be obtained for site mixing.
Anhydrite (Calcium Sulphate) Screeds
Anhydrite screeds are a different type of screed from sand and
cement. The screed is made from calcium sulphate, sand, water
and other chemicals to form a liquid screed. Unlike sand and
cement screeds (which are spread, compacted and levelled),
the screed is poured onto the floor through a delivery hose and
levelled with a dappling bar. Large areas can be covered much
more quickly with this screed type. It is essential, however, that the
floor and edge insulation must be fully waterproofed, by taping and
sealing all joints in the floor and edge insulation.
These screeds are sold under manufacturers trade names and
delivered to site ready mixed.
Whilst a large area of this screed can be installed quickly, it has
the disadvantage of a long drying time and it cannot be laid in wet
areas, or laid to falls.
Liquid Cementitious Screeds
This type of screed is similar to an anhydrite screed but uses
cement instead of calcium sulphate. It is generally much stronger
and can be rapid drying. Although available, it is less common
in use.

36

Tel: 01489 581787 www.warmafloor.co.uk

Expansion Joints/Crack Inducers

All screeds expand and contract to some degree, so allowance has
to be made for this. The perimeter insulation fitted with underfloor
heating allows for some of this, however large areas will need to
have expansion joints or crack inducer cuts in the screed itself to
allow movement and avoid screed cracking. Expansion joints will
also be required to mirror any expansion joints in the floor slab.
These should be as recommended by the screeder or architect.
Day Joints
Day joints are positions where the screed has been finished on one
day and will be carried on the next day. In these positions, to avoid
cracking, the joint needs to be reinforced with mesh to bond the screed
together. Alternatively an expansion joint should be fitted in this position.
Floor Tiles, Marble Floors, Stone Floors
Where the screed is to be finished with a rigid tile, marble or stone
topping, the expansion provisions are very important as screed
movement can crack the floor finish. The flooring should be
designed by the floor installer detailing expansion provision in the
floor tiles themselves. This can then be mirrored with a separate
bedding layer with expansion joints, or in the screed below.
Alternatively, a de-bonded bedding layer for the floor finishes can
be installed above the screed.
Screed Level and Surface Flatness
All screeds have to be installed to a British Standard of level and flatness.
Flatness the variation in gap under a straightedge placed
anywhere on the surface, to be not more than the following:
- 10 mm under a 2m straightedge SR3
- 5 mm under a 2m straightedge SR2*
- 3 mm under a 2m straightedge SR1
* In general use.
Permitted level tolerance from floor datum +/ 10 mm.
Reinforcing Mesh
In sand and cement type screeds the use of D49 mesh can be
used to reinforce the screed to avoid cracking. In areas where a
number of underfloor circuits can come together such as some
manifold locations, or where the screed is below the recommended
thickness, the screed should be reinforced by the installation of D49
mesh, at mid point in the screed, over the underfloor pipework.
We recommend PP fibres as a minimum reinforcement.
Screed Treatment for Finishes
If an adhesive or other finish is to be applied to the screed, it may
not be able to be applied directly; a sealer may be required first.
Always check with adhesive/finish manufacturer.
Remember
No concrete floor will be flat and level on a building site, so it is
best to do a level floor survey to ensure enough depth above the
floor slab is available for the underfloor heating and screed. When
specifying screed depths, it is important to ensure the minimum
specified depth allows for some intolerance in the floor slab.
Always contact the screed manufacturer for specific requirements.

Screed over underfloor heating (floating screeds)

Screed types

Sand and
cement with
added fibres

Enhanced sand and

cement with added
fibres

Enhanced sand
and cement with
added fibres

Anhydrate
(calcium
sulphate)

Flowing
cementitious

Trade Names

Site or plant
mix

- Flexidry
- Tarmac Truscreed
- K-Screed

- Flexidry etc.

- Tarmac Truflow
- RMC Supaflo
- Lafarge Gyvlon

- Ecoscreed

Installation rate m2 per day

100-250

100-250

100-250

500-1000

600

Screed strength

18Nmm2

25Nmm2

30Nmm2

30Nmm2

30Nmm2

Domestic*

65mm

65mm*

65mm

55mm

55mm

Commercial*

75mm

75mm*

75mm

55mm

55mm

Minimum cover over pipework

40

40

40

30

25

Light foot traffic

24-48 hours

12 hours

12 hours

24-48 hours

4 hours

Site traffic

5 days

5 days

5 days

5 days

2 days

Suitable for wet areas

Yes

Yes

Yes

No

Yes

Approx screed drying times

@20oc ambient

refer to
manufacturers
data sheets

1mm per day

up to 40mm the
0.5mm per day

55mm thick

70 days

70 days

60mm thick

80 days

18 days

7 days

80 days

80 days

65mm thick

90 days

20 days

7 days

90 days

90 days

75mm thick

110 days

22 days

7 days

110 days

110 days

Recommended
minimum screed
thickness over
insulation*

Notes:
Drying times - Exact drying times for screed to completely dry are dependent upon temperature,
humidity and air movement in building.
*Cover over pipes - Screed depths stated above allow sufficient cover over underfloor pipework,
allowing for some level of intolerance in floor slab.
Floor coverings - Before application of floor coverings, moisture content of screed must be checked.
Lower screed thickness - Some enhanced sand cement screeds can be installed at a depth less than
those shown in the table, when used with reinforcement - however in all cases this must be checked
and confirmed by the screed manufacturer.

Useful telephone numbers

Flexidry drying times:

Flexi Dry

0845 555 5656

F0 - 3 days

Tarmac

01298 768555

F1 - 7 days

Ecoscreed

01372 842102

F2 - 14 days

Lafarge Gyvlon

01925 428780

F3 - 21 days

37

Components

IV
IV

BLR 02

Modular
condensing
boilers

IV

IV

MV

Air handling unit with heat recovery recuperator.

TP

TP

Night setback
temp. control

IV

Internal sensor

TP

TP

IV

IV

DRV
IV

TP

Extract air from system

air flow

IV

VT return

CO2 sensor for air

quality control

IV

CT return

Ventilation
control
Supply air to system
air flow

Flushing
loop

CT flow
VT flow

Safety pressure
differential valve

TS

Flow
temperature
sensor

Flushing
loop

HL

High limit
sensor

IV & DOC

IV & DOC

CS

Sensor/roomstats operate circuit

actuators on manifolds to control
room temperatures

CS
IV & DOC

IV & DOC

Flushing
loop

Flow

Room
stats/sensor

Room
stats/sensor

10 C
T
MAX

Return

Flow

Return

10 C
T
Max

Typical manifold connection

The optimising weather compensator will adjust water flow temperature

according to outside weather conditions and internal space temperature
sensor setting. Circulating pump self adjusts flow rate to suit demand.

Warmafloor underfloor heating

WIRING CENTRE

fresh air inlet

air flow

Manual
air vent
IV

DRV

CS

CS

DRV

Mixing valve

DRVTP

Inverter pumps

Building management
system with
weather compensator

exhaust outlet
air flow

IV

DOC

Air/dirt
separator

Low loss
header

LSV
DOC

WIRING CENTRE

BLR 01

IV

CS = Commissioning Station
IV = Isolating Valve
DOC = Drain Off Cock
LSV = Lockshield Valve
MV = Motorised Valve
CT = Constant Temperature Flow
VT = Variable Temperature Flow
TS = Temperature Sensor
TP = Test Point
HI = High Limit Sensor

Tel: 01489 581787 www.warmafloor.co.uk

38

Outside
sensor

Typical heating schematic

Control systems

Total Integrated Control Strategy (TICS).

Touch screen technology has enabled system development that
can control up to 32 zones, providing management of temperature,
scheduling, boost, system prioritisation, weather compensation and
multiple heat sources.

Basic Control
Each underfloor heating system will require thermostatic controls.
This can range from the simplistic to very sophisticated systems or
integration to a full BMS (Building Management System) to ensure
operation is compatible with the building use and occupant comfort.
Basic controls are thermostats mounted on to a wall surface or on a
standard wallbox.

Warmafloor controls - thermostats and sensors

Operation of the system is via a central control unit that is located

where the specifier/user wishes. A simple intuitive menu system
enables operation of the underfloor heating to be easily configured.
20.5oc
20.0oc
19.5oc
P-band 4oc

Standard thermostat
230v

0-100% Heat output

Tamperproof thermostat

24v

230v

Size - 85(w) x 85(h) x 31(d) (mm)

24v

The thermal
actuator is
gradually closed
as the required
room temperature
is approached,
thus providing
more accurate
control and
saving energy

16.0oc

Size - 85(w) x 85(h) x 31(d) (mm)

Wiring Centres
Wiring
Centre

Console

Kitchen

Dining
Room

Sitting
Room

Study

Bedroom

Towel
Rails

Installation of the 12 volt system is straightforward, using a single cable

bus wiring network system. In essence this eliminates more elaborate
wiring associated with standard 240v cabling. The system is low
voltage and therefore safe using 12v to illuminate the room sensors.

240V/24V
Wiring centres can be provided to interface between the room
thermostats and the manifold circuit actuators. The wiring centres
can also operate the manifold circulation pump (if fitted). The wiring
centres have a volt free contact for remote boiler demand or BMS
interface/signal.
- Supply to all wiring centres is 240 volt.
- 24 volt wiring centres have an inbuilt transformer.
Remote sensors

Should a building be altered or extended in the future, the system

is flexible to include additions of room sensors, as each has its
own unique identification code and the single wiring system can be
extended into the new areas.
Underfloor heating systems require minimal maintenance. The pump
and actuators on the manifold require exercising during extended
periods of inactivity. The control system has a built in exercise
programme to help eliminate costly maintenance call outs.
Underfloor heating is the most energy efficient form of heating a
space available. To further maximise these efficiencies our TICS
utilises P.I. (Proportional Integration) control. P.I. control ensures
rapid and stable control of room temperature eliminating over or
undershoot. The result is an additional and substantial energy saving
and subsequent cost reduction.

Nipple sensor

Remote sensor

Thimble sensor

39

At your
service
System design
With our complete portfolio of systems,
we can assist you in selecting the most
effective solution for your project. Our
design teams will produce scheme
layouts and CAD detailed drawings
showing full pipework layouts, pipe
lengths, thermostat and manifold
positions, controls, wiring diagrams,
and attendant building details.

CPD Seminars
and training
sessions
call +44 (0) 1489 581787
or www.warmafloor.co.uk

System installation
We provide a complete comprehensive
design, manufacture and installation
service, using the expertise of our own
fully trained workforce. In addition,
systems are available on a supply-only
or a design and supply basis; for those
qualified to carry out the installation
work themselves.

System commissioning
Once the underfloor installation and
the rest of the building programme is
completed, our specialist teams can
return to site during the commissioning
process and undertake responsibility
for system balancing and system
operation testing. We can provide full
record drawings together with testing
and balancing certificates and O&M
documents for the whole building.

System after care

Once the system is commissioned and
the building is occupied, we can offer a
bespoke aftercare service to carry out
routine inspection and maintenance; to
ensure optimum performance. We can
assist in rebalancing the system when
parts of the building undergo a change
of use.

WARMAFLOOR (GB) LTD

Concorde House
Concorde Way
Segensworth North
Fareham
Hampshire PO15 5RL
T: +44 (0) 1489 581787
F: +44 (0) 1489 576444
E: sales@warmafloor.co.uk
For further technical
information and latest
company news, visit our
website at
www.warmafloor.co.uk

UNDERFLOOR HEATING & COOLING