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TECHNICAL SPECIFICATION
Coltman Floors And Roofs The gap between the top of the wall/steel beam and the
Units comprise of hollow and solid prestressed concrete, soffit of the floor unit due to camber is to be filled solid with
normally 1200mm wide placed side by side with a grouted mortar by the Principal Contractor before construction above
joint. The units are manufactured with a concrete having a the slab proceeds.
minimum cube strength of 30 N/mm2 at transfer and Side Bearings
50N/mm2 at 28 days. Prestressing wire is stress relieved and
treated for low relaxation.
The Coltman flooring units are manufactured by the long
line prestressed method using slip form techniques on heated
steel beds within a factory environment. Coltman units are
sawn to length on the manufacturing bed and are supplied
as standard with plain sawn ends and open cores.
Cross sectional and length tolerances are within the limits
set out in BS 8110 and are subject to stringent quality
control checks.
Structural design is in accordance with the Gap due to camber to be solidly filled
recommendations of BS 8110 “The Structural Use Of with mortar before construction
Concrete”. above the slab proceeds
The standard Coltman floor unit is designed for a mild
exposure condition as defined in BS 8110, other exposure Internal Load Bearing Wall
conditions can be considered subject to consultation with the
Coltman Technical Department.
The standard Coltman floor unit is designed to meet
Class 3 serviceability requirements as described in BS 8110.
Designs to Class 1 and Class 2 are available if required. Gap due to camber to be filled with
Camber 100 'Dry pack' mortar before construction
minimum above the slab proceeds
Prestressed units have an inherent upward camber and
due allowance should be made in any finishes to cater for
this particularly where a rigid insulation board or a floating
timber floor is to be placed onto the top of the floor unit. In
Supports
Structural supporting walls for Coltman units are to rise
these situations a levelling screed will need to be applied by
from proper foundations and the adequacy of all bearings is
the Principal Contractor prior to the laying of the finish.
the responsibility of the Principal Contractor.
Differential camber between adjacent units should be
The stability of the supporting structure must not be
within the tolerances set out in BS 8110 except for areas of
adversely affected by the installation of the precast concrete
floor where the adjacent spans of the units are of different
units.
lengths or where large holes are to be formed within the
When designing bearings consideration must be given to
middle third of the unit.
the standard method of fixing precast concrete units,
Consideration must also be given to both floor and ceiling
particularly the operation of final alignment. Construction
finishes where floor spans are perpendicular as steps will
loading arrangement/forces may be more onerous than the
occur between units.
final working condition.
The camber of Coltman units will generally comply with
Where masonry supports are provided the Principal
the recommendations of BS 8110 and are predicted to be
Contractor should ensure that the mortar is fully cured before
approximately 1/300th of the span.
the floor units are placed into position. This is particularly
relevant where retarded mortars are being used. A curing
period of 3 to 7 days should be allowed for traditional
mortars and advice of curing times should be confirmed with
manufacturer where retarded mortars are used. Accurate and
Camber level structural seating shall be prepared by the Principal
L/300 Contractor.
Lightweight blocks are not suitable to provide bearings for
precast concrete units and their use in this situation should
be avoided. Where steel sections are to be utilised within
Length (L) masonry structures suitable arrangements must be made to
fix the steel beams down to padstones to prevent movement
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and rotation during installation. If this is not practical, Any material placed between the structural seating and
temporary props are to be provided to ensure stability. In the unit soffit may result in a variation to our estimate.
certain instances it may be necessary to utilise both a bolted Normal bearing requirements for Coltman units are
fixing and propping particularly where eccentric loads are to 100mm on brickwork and 75mm on steel and concrete but
be placed on a support beam. these may be reduced in certain circumstances subject to
Where precast units are supported on a cavity wall the design criteria.
outer leaf of the wall must be built upto within 225mm of Where precast concrete units are supported on steel shelf
the bearing level to maintain stability. angles then the outstanding leg of the angle should not be
In locations where the precast concrete units are to be less than 150mm and should project a minimum of 50mm
supported on walls less than 190mm thick then temporary beyond the top flange of the beam.
props or other means of bearing enhancement must be
employed, designed and erected by competent persons. Steel Shelf Angle Bearing
Props and timber runners are to be positioned at bearing
level to give lateral support to the wall during installation.
30
Dual Bearing Minimum clearance
140 In situ infill and
Minimum width of wall reinforcement by Coltman
Props to provide lateral
Timber just below
bearing level
stability to single skin 50 150
load bearing wall Shelf angles to project 150mm minimum
a minimum of 50mm beyond outstand leg
top flange
Consideration must also be given to the design and
stability of lintels during the construction phase. It may be Contact Coltman Technical Department
necessary dependent on type of lintels to prop the inner skin at an early stage if any variation to
until the construction is complete. this detail is to be considered
Propping Infill concrete Infill concrete
Flange flush with top of slab
Lintel
The inner skin should be propped
where there is insufficent masonry
to counterbalance the load imposed
during the construction phase. 75
Minimum Bearing
Lintels should be designed with the
Prop
construction phase loading in mind, as
this type of lintel does not achieve
full load capacity until construction
Fixing
is complete.
Coltman installation gangs are fully experienced and
trained to handle and place precast concrete in accordance
with the Code of Practice For The Safe Erection Of Precast
Concrete.
The foregoing comments apply equally to other types of
Where erection is to be carried out by others than
structures with particular attention being required in the case
Coltman it is the responsibility of the Principal Contractor to
of isolated piers and walls or toothed walls where temporary
ensure that the fixing gang is competent and capable of
means of support may be required.
carrying out the work in accordance with the Code of
In all instances the temporary supports/propping should
Practice For The Safe Erection Of Precast Concrete. Copies of
be designed by a competent person and must be in position
this code are available upon request.
prior to the installation of the precast concrete units.
Layout drawings are prepared for use during site erection
Where precast concrete units are to be fixed within a
and these should be followed carefully and accurately.
steel frame building it is essential that sufficient structural
steelwork, sheeting rails, purlins, bracings, etc., are omitted
to allow for our standard fixing procedures. Grouting
Additional steel supports may be required where floor When fixing we include for filling the joints between units
units are required to notch around columns, particularly with Grade C25 concrete, but not for screed or other
around the perimeter of the building. finishes.
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Make Up The visual effect of differential camber as previously
Each area of flooring is set out using standard units and described should be considered when an exposed soffit finish
may incorporate reduced width units or in situ concrete strips or direct decoration is to be utilised.
to make up. Any strips should be cast in situ during site The application of plaster should be carried out in
erection, unless otherwise specified. Stripping and disposal accordance with the recommendations of British Gypsum.
of formwork to be carried out by others at no cost to We do not recommend direct plastering to units exceeding
Coltman. 7.0m span.
Our estimate does not include for any in situ strips that The application of Artex to the soffits of our units should
may be required adjacent to steel beams, or to the edge of be carried out in accordance with the Artex specification
any bay of units, or for making good around pipes, which is available from us upon request.
stanchions or making up faces of large openings. Units with closed ends may accumulate water within the
cores due to exposure to weather or from subsequent
Holes building operations. The Principal Contratctor should drill
Small holes up to 50mm dia can be drilled on site on the weep holes to release any trapped water or keep the weep
centre lines of the hollow cores, care being taken to avoid holes clear where they are provided by Coltman. The
cutting or exposing reinforcement. The spacing of these holes Principal Contractor should be satisfied that all trapped water
should be limited to 400mm centres in each direction. has been released prior to the application of finishes.
Larger holes can be formed during manufacture, dependent
upon design criteria. The edge of the hole may be located at
70mm plus increments of 100mm from the side of the unit. Recommended type of fixing for heavier loads.
(Fire protection may required by others)
Service Ducts
Metal Trimmer strap
Fixing zone
Tapcon or similar fixings
may be drilled into the
Toggle or similar type fixings may area's directly below the
be made into the areas directly cores to provide fixings
below the cores. Expanding bolt type for batten and plasterboard
fixings are not recommended. ceilings.
Ceiling Fixings
100 100
26
(148/198)
(200/250)
Holes for large services , flues , soil and vent pipes and the like
70
150
98
may be formed during manufacture. Small holes may be drilled
on site through the cores of the units.
Metal straps are used to trim larger duct openings subject to design
criteria and should be fire protected by the Principal Contractor.
26
Prestressed wire locations
Screed 1. Shot fired fixings are not permitted.
A non-structural sand and cement or grano screed is 2. Service and ceiling loads must not exceed those shown
normally laid by the Principal Contractor over the floor on the slab general arrangement drawings.
3. Fire protection may be required where a fixing
(before plastering the soffit) to provide a level surface for penetrates the floor slab.
finishes. A minimum screed thickness of 40mm is suggested 4. The adequacy of the fixing is the responsibilty of others.
with due allowance being made for the camber of units. It is
strongly recommended that a light two-way reinforcing fabric
is incorporated in the screed. Anti-crack reinforcement in the
Fire Resistance
Coltman units are designed in accordance with BS 8110
screed should always be provided by the Principal Contractor
to provide a minimum fire resistance of 1 hour. 1.5 and 2
over supporting beams and walls.
hour fire resistance elements as defined in BS 8110 are also
Soffit available. The fire resistance may be enhanced further by the
Soffits of Coltman units are suitable for the application of application of appropriate finishes.
plaster finishes. Small surface blemishes may be expected
but the surface will be free from large voids. Stopping off of Sound Insulation
air holes and rubbing down of any casting bed marks are not (See Building Regulations Approved Document E and Robust
included within our offer. Details Ltd Publication: Robust Details Part, “Resistance To
The Principal Contractor is responsible for ascertaining The Passage Of Sound”.)
the suitability of our floor units, by inspection at our factory if Where the precast concrete units are forming a floor
an exposed soffit is required or if the soffit is to receive direct which is separating individual dwellings, the following points
decoration in the form of paint, Artex, etc. should be considered:
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It is important that the project Architect ensures the PC Coltman Precast Concrete Staircases
floor depth and average density is compatible with the
intended floor and ceiling finish, if full compliance with
Building Regulations Part E and or Robust Details Ltd
Publication: Robust Details Part E, “Resistance To The Applied finish to landing area
by others to accommodate
Passage Of Sound” is to be achieved. manufacturing , building and
fixing tolerances.
Typical End Bearing
Finish
PC concrete floor plank
Ceiling
Dry bearing SECTION A - A
Any resulting voids between the top
of the inner leaf and the underside
of the plank to be filled with a
flexible sealant (sealant provided
and installed by General Contractor).
Typical End Bearing
P.C Landing
P.C Landing
Typical Side Bearing
A A
Finish
PC concrete floor plank
Ceiling
Gap due to camber to be solidly
filled with mortar before the Units comprise of bar reinforced concrete stairflights and
construction above slab proceeds. landing slabs, manufactured with concrete having a
Where the gap becomes too small
to be filled with mortar it should be
minimum cube strength of 35N/mm2 at 28 days. The
filled with a flexible sealant (mortar staircase units are cast from steel or high quality timber
and sealant provided and installed moulds. Treads, risers and strings of flights, sides and soffits
by the General Contractor).
of landing slabs will be as cast from the mould to produce a
type “A” finish, as described in BS 8110. Soffits to
Composite stairflights will be trowelled smooth and tops of landing slabs
In composite construction, where a structural concrete left to receive screed by others.
topping acts in conjunction with the precast units, the units The exposed concrete surfaces will be left suitable to
may require to be supported on a pre-erected, fully braced receive Artex or similar direct, but further surface preparation
propping system at centres defined on the layout drawings. may be required by others if a paint finish is to be applied.
Props should remain in position until the structural topping As soon as the staircases have been installed they should
has reached its design strength or as stated on the layout be protected from damage by following trades. In the case of
drawings. The concrete topping should be placed in supply only contracts the Principal Contractor should satisfy
accordance with BS 8204 Parts 1 and 2. A structural himself of the quality prior to offloading. We cannot accept
topping specification is available from our Technical responsibility for damage reported to us after the staircase
Department upon request. units have been offloaded.
Balustrade fixings can be provided in the form of pockets.
Disproportionate Collapse However we would generally recommend that fixings for the
Requirements for disproportionate collapse must be balustrade be drilled on site by others.
specified by the Project Engineer responsible for the overall All lifting pockets used during installation to be filled in
design of the structure. Where structural ties are specified, by others than Coltman.
they should be designed and detailed by the Project The staircase units have lifting anchors cast in during
Engineer. If the proposed ties are to be cast into details pre- manufacture. Where installation is not being carried out by
formed within the PC floor, it is important that the Project Coltman then lifting eyes need to be obtained from an
Engineer checks with Coltman that the proposed details are approved supplier. Our Design Department will advise you of
achievable. the type and number required.
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LOAD SPAN TABLES
Coltman Hollow Core Slabs
These tables are for guidance purposes only. Where deflections natural frequency etc require consideration please contact our Technical Department.
2
(The design includes for self weight and an allowance of 1.75 Kn/m for finishes, but does not include for any partition allowance or the effect of any service holes)
Maximum Permissible Spans In Metres
Live Loading (Kn/m2)
Unit Cross Section
0.75 1.50 2.00 2.50 3.00 3.50 4.00 5.00 7.50 10.00 12.50 15.00
Depth - Self Weight
(Solid slab)
5.00 5.00 5.00 5.00 4.88 4.70 4.55 4.27 3.76 3.40 3.12 2.91
100mm Deep - 2.36 Kn/m2
7.50 7.50 7.50 7.50 7.26 7.00 6.77 6.36 5.60 5.06 4.65 4.32
150mm Deep - 2.35 Kn/m2
(Sound slab - 300 kg/m2)
7.50 7.50 7.50 7.35 7.08 6.85 6.63 6.26 5.54 5.03 4.63 4.32
150mm Deep - 2.94 Kn/m2
10.00 10.00 9.86 9.48 9.14 8.84 8.56 8.07 7.15 6.49 5.98 5.57
200mm Deep - 2.94 Kn/m2
12.50 12.05 11.64 11.24 10.87 10.53 10.23 9.69 8.64 7.87 7.28 6.80
250mm Deep - 3.66 Kn/m2
Coltman Composite Slabs
Hollow Core Slab Solid Plank And Grade 35 concrete with A142 mesh
reinforcement placed directly onto
And Structural Structural Topping the floor slabs
Topping
2
(The design includes for self weight and an allowance of 1.75 Kn/m for finishes but does not include for any partition allowance or the effect of any service holes)
Maximum Permissible (Unpropped) Spans In Metres
Live Loading (Kn/m2)
Total Total
Depth of Depth of
Struct self
P.C unit topping
depth weight 0.75 1.50 2.00 2.50 3.00 3.50 4.00 5.00 7.50 10.00 12.50 15.00
(mm) (mm) 2
(mm) (Kn/m )
75 75 150 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.73 3.57 3.43
75 125 200 4.95 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.75 3.67 3.59
100 50 150 3.79 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 4.69 4.36 4.04 3.54
100 100 200 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 4.89 4.70 4.52 4.37
150 50 200 3.83 7.50 7.50 7.50 7.50 7.50 7.40 7.25 6.98 6.40 5.86 5.43 4.95
150 75 225 4.43 7.50 7.50 7.50 7.50 7.50 7.39 7.27 7.04 6.56 6.16 5.82 5.54
200 50 250 4.49 10.0 9.80 9.58 9.37 9.18 9.00 8.82 8.50 7.82 7.22 6.71 6.06
200 75 275 5.09 9.90 9.61 9.44 9.27 9.10 8.95 8.80 8.53 7.94 7.46 7.05 6.70
250 50 300 5.25 11.42 11.06 10.82 10.61 10.41 10.21 10.03 9.68 8.93 8.23 7.68 7.22
250 75 325 5.85 11.15 10.84 10.65 10.47 10.29 10.13 9.97 9.67 9.03 8.50 8.05 7.62
Partition loadings should be determined in accordance with clause 5.2.2.2 of BS 8110. Line loads should be converted to imposed blanket loads for preliminary design
purposes. Minimum topping depths are taken at centre of span therefore due allowance should be made for camber when determining overall floor depth.
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Site Dimensions Physical
We do not allow for taking site dimensions. It is the Appearance - Prestressed Floor Units: Grey solid
Principal Contractor’s responsibility to provide all necessary or with longitudinal hollow cores
information and ensure that the dimensions on our approved within depth of unit.
drawings are compatible with the physical dimensions of the Stair/General Precast Items: Grey
structure as built on site. solid units occasional protruding
steel bearing cleats.
Testing
We shall be pleased to provide test cubes, samples of Hazards - Skin irritation or dermatitis unlikely when
materials etc., for collection by the Principal Contractor from handling the product in its solid form.
our works for delivering to an approved testing laboratory. Operatives should be aware of the abrasive
The cost of collection, delivery and testing to be borne by nature of the product. During cutting,
the Principal Contractor. drilling and other operations where dust is
created there is a risk of inhaling dust
Inspection Of Finished Work containing silica compounds and steel
The Contractor should ensure that our products and filings, which if inhaled can lead to long
workmanship are to the satisfaction of all concerned whilst term health hazards. The airborne dust will
our men are on site. Liability will not be accepted for defects irritate the eyes.
not notified to us within three days of erection.
PPE/Precautions - Gloves, suitable for handling abrasive
Health & Safety File Information material. Eye protection to prevent dust or
Coltman Precast Concrete Ltd will provide ”As Installed” splinters getting into the eyes. Respiratory
drawings and calculations at completion of the installation protection to be worn at all times when
these will include any changes from the original floor layout. carrying out operations that generate dust.
The Principle Contractor will be responsible for recording any Selection of respirator will depend upon
amendment to the installed drawings thereafter. proximity and concentration of dust. Dust
masks will normally be adequate unless
Loadings working in confined spaces.
The floor unit layout drawings and calculations detail the
loads for which the floor has been designed. Care should be Area of Use - Precast concrete flooring, stair components
taken to ensure that during construction and during the life and other general precast concrete
of the building that both the design loads are not exceeded products for use in the construction
and that additional holes are not introduced without the industry.
approval of the Coltman Design Department. No further
partitions other than those shown on the Coltman drawings Spillage Requirements - Not applicable.
should be built off the floor units again without prior
consultation with the Coltman Design Department. Storage Requirements - Not applicable.
Maintenance Special First Aid - Not applicable.
There are no maintenance requirements.
General
Demolition The illustrations shown and details given in other parts of
Advice on demolition should be sought from a competent this brochure also constitute part of the Standard Technical
person who has access to the Health & Safety file. Specification. For further details, please contact our Technical
Department.
COSHH Assessment Our policy is one of continious improvement, and we
reserve the right to change the specification without notice.
Product - Precast concrete products consisting of
Portland cement, sand, limestone and
quartz aggregates. Can contain calcium (All illustration dimensions are mm)
silicates and quartz particles. Published October 2005.
BS EN ISO 9001:2000 ISO 14001
Registered Firm REGISTERED FIRM
Coltman Precast Concrete Limited London Road Canwell Sutton Coldfield West Midlands B75 5SX. Tel: 01543 480482 Fax: 01543 481587
Website: www.coltman.co.uk E-mail: general@coltman.co.uk
Registered Address: Melsonby Terrace 31 Chorley Old Road Bolton Lancs BL1 3AD Registered No. 1032721 London
