CARSE OF GOWRIE SUSTAINABILITY GROUP
Circumstances can differ from one property to another. Any information or advice is for guidance and
is given in good faith but without warranty. Whilst we have made every effort to ensure its accuracy
and completeness neither the author nor the Carse of Gowrie Sustainability Group nor its office
bearers can accept any liability arising from errors or omissions.
Advice sheet 4 Measures to make your property more resilient to flood damage
The Scottish Government has announced its commitment to sustainable flood
management.1
“Sustainable flood management provides the maximum possible social
and economic resilience against flooding, by protecting and working with
the environment, in a way which is fair and affordable both now and in the
future.”
Resilience in turn is defined as: “the ability to recover quickly and easily”.
Housing stock turnover is low with existing stock making up 99% of all homes at any
given year2. If this rate is sustained, the majority of the housing stock will continue to
consist of existing buildings for many decades to come. The Sustainable
Development Commission’s estimates for the UK’s 2050 housing stock suggest that
around 70% has already been built3. Not only that, but architects are still not trained
in taking climate change into account and in the whole world there is still only one
text book on the subject.4
We are very fortunate in Scotland that building regulations for new build properties
do require considerable resilience against flooding and the Scottish Building
Research Establishment at East Kilbride is a world leader in this subject.
Nevertheless for existing buildings it is largely left to the property owner to make
decisions on retrofitting for resilience.
Resistance
But first look at resistance, how to keep the water out of your property. A very simple
precaution is simply to keep watercourses and drainage gullies clean, and we are
‘Flood Risk Management (Scotland) Act 2009: Delivering Sustainable Flood Risk
Management’ The Scottish Government, Edinburgh 23 June 2011
http://www.scotland.gov.uk/Resource/Doc/351427/0117868.pdf
accessed 24.6.11.
2 Your home in a changing climate. Retrofitting Existing Homes for Climate Change
Impacts, Three Regions Climate Change Group (2008)
3 StockTake: Delivering Improvements in Existing Housing, Sustainable
Development Commission (2007) [online] www.sd-www.sdcommission.org.uk/publications/downloads/Stock_Take_UK_Housing.pdf
4Roaf, S. Crichton, D., and Nicol, F. , 2009. “Adapting Buildings and Cities for
Climate Change.” (Second edition) 384pp. Architectural Press, Oxford. ISBN 978
1 85617 720 7.
1 1
fortunate that in Scotland, unlike England, there are statutory duties on local
authorities to do this and you can report any concerns to them.
If the problem is surface water, the answer may be a flood wall around your garden.
This can be constructed of a double layer of engineering bricks, covered in a mound
of earth to form a “berm”. For access, you can either have ramps or use a
demountable flood defence system (see advice sheet 1). This is more difficult for
semi detached or terraced properties unless you can persuade the neighbours to join
in. Again we are fortunate in Scotland in that such local flood defences are allowed.
They are not allowed in England. However you should make sure that in defending
your property you are not simply passing the flood problem on to a neighbour.
For periods of heavy rainfall wide storm gutters should be provided, and kept clean.
Walls, and especially their bases, should be protected from driving rain and splash
back, for example by having gravel beds at the foot of walls and making sure that
gardens slope away from the wall. Make sure that the wall has a damp proof course
(dpc) at least 150mm above the ground with nothing to bridge the dpc.
Many floods are actually caused by backup in the drains, leading to water
overflowing from ground floor baths or toilets. The ideal situation here is a one way
flap valve fitted into the sewage system. A stopgap solution is a bladder from a
football which can be partially inflated and pushed down the toilet, and held in place
with a sandbag.
Resistance measures to flooding are about identifying and blocking all potential entry
points. For short duration floods, entry points include doors, air bricks, sinks and
toilets, and gaps in external walls around pipes and cables. For longer durations,
measures will need to be taken to prevent water entering through the walls.
For shallow floods of less than 1 metre depth demountable defences may be the
answer (see advice sheet 1).
In deep floods (over 1 m), you may have to resign yourself to letting the water in
because a large imbalance between the water level inside and outside can lead to
structural damage to your walls.
This is where resilience comes in.
Resilience
Resilience is about reducing the time and cost of cleaning up after a flood, and
avoiding the need to replace appliances, floor and wall coverings etc.
It is all about adaptation and if you are in a flood hazard area resilience should be
considered whenever you are carrying out maintenance or redecoration. In
particular it should be considered when repairing flood damage.5
Here are some ideas:
5
Crichton, D, 2007a What can cities do to increase resilience? Phil. Trans. R. Soc
10. 1098 pp1 – 11. Royal Society, London.
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Fitting rising hinges so doors can be removed, and laid flat to dry without
warping.
Using water-resistant paint or ceramic tiles for floors or the lower portions of
internal walls,
Raising electrical points above flood level with wiring drops from above
Relocating meters and the boiler above flood level
Replace carpets with vinyl and ceramic tiles and/or rugs.
Avoid using chipboard for floors or kitchen cabinets. Choose cabinets on
legs. In extreme cases, such as Shrewsbury, families have abandoned the
ground floor altogether and use it for car parking.
Some insurance companies and building contractors will put pressure on you to
replace everything with new materials. This is not always ideal. For example if you
have doors made of Victorian pitch pine, be aware that this will dry out very well after
a flood if laid flat and allowed to dry slowly. A modern replacement of hollow mdf or
chipboard may be quick but will disintegrate if you have another flood. It is virtually
impossible to buy new doors made of pitch pine, and builders do very well from
taking pitch pine doors from flooded houses, drying them out and selling them to
architectural salvage merchants.
Resilient reinstatement
Insurance companies may resist “resilient reinstatement” on the grounds that it is
what they call “betterment”. However if you insist, they may agree if you pay the
difference in cost which may be quite small. This will stand you in good stead next
time there is a flood, especially if you find yourself without insurance cover.
Flooding can result in massive amounts of building materials being sent to landfill
and replaced with new high embedded energy materials. Where buildings are
constructed in high flood risk areas they should not have any insulation or absorbent
materials at all, because this increases the cost of repairs and drying out time and
energy after a flood.
© 2012 David Crichton for original material unless otherwise indicated. All rights reserved. Extracts
may be quoted for review or research purposes with due acknowledgement.
The rights of David Crichton to be identified as the author of this work have been asserted in
accordance with the Copyright, Designs and Patents Act 1988.