2

HSEH 4120
Housing and
Health - 3
 HSEH 4120
Housing
and Health

Section 3 House construction

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HOUSING CONSTRUCTION

All buildings should be:

• located and designed in the context of the local
development plan, and
• constructed in compliance with local construction laws,
standards and guidelines.
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In Qatar, the Ministry of Municipality & Planning Affairs deals
with urban planning issues.

The Qatar Construction Specifications 2010 are administered by

the Ministry of Environment.
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The Qatar Construction Specifications 2010 are in line mainly
with British and American standards.
For example, most construction engineering specifications
reference British Standards.
Fire protection requirements are to National Fire Prevention
Association codes from the USA.

Kelly, R., Clyde & Co. Qatar Construction Specifications 2010 – Legal Considerations. IOSH Conference paper, April 2013.
Relevant Standards and Guidance, Section 10, Lusail Starter Pack, March 2012.
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Is there a difference between a law and a standard?

Is there a difference between a standard and guidance?

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Planning consent may be required to ensure a
development proposal is in line with the local
development plan, and fits in with its surroundings.
Location plans, design drawings and sketches, even
models, may be used to illustrate the proposal.
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Before consent to build is granted, compliance with the local
building/construction code or standard must also be demonstrated.

This is done using structural drawings supported by information on

materials, fittings and methods.

Utility installations (water, drainage, power, HVAC) must also meet

regulated standards.

Much of the building specification relates to things which are below

ground or within structural elements.
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Standard views
in building
drawings
include these.
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“Kerala”
house
Floor plan
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Houses are built from the ground up.

After the site is cleared:

• the foundations are laid,
• the walls and floors are built, and
• the roof is installed.

Underground utilities may be brought in at an early stage. External

doors and windows may also be fitted as soon as possible to provide
weather protection.
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Foundations transfer the load of a building to the
supporting soils or rock.

Housing foundations can be divided into two broad

categories:
• Shallow foundations (strip, raft, pad) are used where the
soil at that level can support the load.
• Deep foundations (say >3m) transfer loads through weak
upper strata to a more competent one at depth.
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Shallow strip
foundations
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Deep (pile) foundations

Sources:
http://www.theconstructioncivil.org/types-of-piles-deep-foundations
http://environment.uwe.ac.uk/geocal/foundations/Fountype.htm
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Walls are vertical elements that delineate the building and
support its superstructure. In housing, the external walls
generally support the roof. Internal partition walls are used to
divide the space into rooms and may support upper floors.
Floors are horizontal structures that support the occupants and
contents of a room.
They also divide a building into “floors” (storeys). Above the
ground floor, the underside of each floor is the ceiling of the
floor below.
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Doors provide access. In external walls they also provide security
and weather protection. Doors in partitions provide separation
between rooms, and privacy.
Windows can provide natural light and ventilation.

Doors and windows should maintain required thermal and sound

insulation properties of the walls.
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Structural Safety
Objects falling from the fabric of a building and as a result causing injury are very serious but
extremely rare. Potential injuries range from minor bruising to death.
The most common incident is for a fixture …to fall from the ceiling or wall... However, the most
common part of the fabric of buildings to fall and injure someone is ceiling plaster.

Housing Health and Safety Rating System Operating Guidance, pp. 171-4. ODPM, 2006
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The foundations and load bearing external walls should be designed, constructed
and maintained to be of sufficient strength to support the weight of the building,
fittings, furnishings and its users.
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Differential settlement
Every building settles (sinks) during and after construction.
Differential (uneven) settlement happens when one part of a building sinks more than another. It
happens rarely, but can be a major problem in small residential buildings.
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Differential
settlement!

Campanile
Piazza dei Miracoli
Pisa, Italy
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Openings (doors, windows)
should provide for proper
distribution of the load above.
The roof structure should be
strong enough to support the
weight of the covering, be
securely fixed and cope with wind
and weather imposed loads.
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• Home inspection issues (poor inspection)

• 6:20http://www.youtube.com/watch?v=nYeXJ3TOmAI
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Structural dampness is a very common issue.
It can be due to:
• damp rising from the
ground by capillary action
(rising damp)
• penetration of rain/snow
through walls or roof
(penetrating damp)
• condensation.
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Rising damp
Physics says that, partly
due to surface tension,
water will rise through
porous material
(see right).

Rising damp can be reduced by moving water away from the structure. Building
construction should also incorporate waterproof barriers [damp-proof course (DPC),
damp-proof membrane (DPM)] in any building element in contact with the ground.
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Preventing
rising damp
requires
damp-proof barriers
in floor (DPM)
and walls (DPC).
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Penetrating damp
Water can penetrate walls and roofs, commonly around openings
(windows, doors, vents and chimney penetrations) and through
faults such as damaged flashings, missing pointing or settlement
cracks.

Sometimes cavity walls are

bridged by (e.g.) concrete
dropped during construction.
This can also provide a route
for damp penetration.
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Diagnosing dampness problems

Cavity wall bridging

• http://www.youtube.com/watch?v=zDIQ4dO_9gQ 6:15

Mould or efflorescence?
https://youtu.be/MJc400A33sE

Moisture meter
https://www.youtube.com/watch?v=0wBtXZto2YI
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Condensation
Warm air can hold more water vapour than cool air.
Condensation is caused when moisture-laden
air comes into contact with a cold surface –
the air is cooled to the point where it can no
longer hold its burden of water vapour.

At this point, known as the "dewpoint," water

“condenses” from the air, and is seen as
dew drops on surfaces.
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Condensation (contd.)
Condensation frequently happens on wall and ceiling surfaces, as these surfaces are
often cooler than the room air temperature. On windows or gloss paint this is
obvious.
Permeable surfaces can absorb the moisture so condensation is less obvious.

Water can also condense within a building element such as a wall or roof. It may not
be immediately apparent but can cause serious damage.
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Diagnosing dampness problems
Correct diagnosis is vital for effective treatment. The
Building Research Establishment in the UK has found that
only 10% of cases it investigated were due to rising damp.
Wrong diagnosis has resulted
in many cases of expensive
treatment of rising damp
which was not present.
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Diagnosing dampness problems

These thermal and optical images of the corner of a room show the relationship
between cold and condensation.
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Health impacts of damp
Moisture is essential for the growth of moulds. High indoor humidity also
contributes to increased dust mite populations.
In the UK 1,500 people a year die from asthma, of which 60% has been attributed to
dust mite allergy.
20-30% of asthma sufferers are sensitised to mould spores.
1 in 8 children in the UK suffers from asthma.

Housing Health and Safety Rating System Operating Guidance, p. 53. ODPM, 2006
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The World Health Organization
Regional Office for Europe
states “Occupants of damp
or mouldy buildings are at
increased risk of experiencing
health problems such as
respiratory symptoms,
respiratory infections,
allergic rhinitis and asthma.”

WHO-EURO, Damp and Mould – Health risks, prevention and remedial actions. WHO, Copenhagen, 2009.
http://www.euro.who.int/__data/assets/pdf_file/0003/78636/Damp_Mould_Brochure.pdf
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However, WHO has demonstrated that remedial action works.

“Research shows that people living in well-insulated and

adequately ventilated accommodation are less likely to visit their
doctor or be admitted to hospital due to respiratory conditions
than those living in damp homes.”
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WHO recommends the following 3 steps.

1. Detecting and locating the source of the moisture problem;

2. Removing the mould; and

3. Taking action to control excessive

moisture and condensation.
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1. Detecting and locating the source of the moisture problem

Key message: Moulds only grow when there is sufficient

moisture.

When mould appears, the first task is to try to establish where

the moisture is coming from.
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2. Removing the mould

Key message: After identifying and reducing/removing the moisture

sources, the next step is to decide whether removing the mould from the
affected areas is something that can be managed without professional
help.
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3. Taking action to control excessive moisture and condensation

Key message: If your problem is not from a leak or a faulty or non-existent

damp-course, it is probably caused by condensation.
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Many mould problems are not immediately apparent.

• In many cases moulds grow within building elements, for example through insulation materials
or on the rear surface of wall boards. Destructive testing/sampling or remote imaging may be
needed to identify it.
• Moulds of similar colour to the substrate may not be visible. Black moulds tend to be obvious
on light surfaces where light-coloured moulds, which may be equally prevalent, cannot be
seen.
• Moulds on carpets and soft furnishings may only be detectable by sampling.
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How to stop condensation and mould

• http://www.youtube.com/watch?v=Oj99RNY55Es

• 8:46

• https://www.richardsonandstarling.co.uk/wet-dry-rot-differences/