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Flood Resilient Design

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Summary: Resilient Design is when you choose materials and or layout for your building to minimise damage from flood water when it flows in to property. Examples might be using solid (block / brick) walls for internal partitions, and setting electrical sockets higher than normal.

Material Choices

The below materials can be chosen when building in flood zones. Maximizing use of materials such as engineering brick, and concrete block increase resilience. Materials such as plaster board do not behave well, when they get wet and should be avoided.

Material Water Penetration Drying Ability Retention of pre-flood dimensions
Engineering bricks (Classes A and B) Good Good Good
Facing bricks (pressed) Medium Medium Good
Facing bricks (handmade) Poor Poor Poor
Concrete (3.5N, 7N) Poor Medium Good
Aircrete Medium Poor Good
Timber board      
OSB2, 11mm thick Medium Poor Poor
OSB3, 18mm thick Medium Poor Poor
Gypsum plasterboard      
Gypsum Plasterboard, 9mm thick Poor Poor Poor
Below d. p.c. 1:3(cement:sand) Good Good Good
Above d. p.c. 1:6(cement:sand) Good Good Good


General advice for Flood Resilient Design

Where concrete ground floor slabs are used, the block work substructure is often the weakest point in terms of water penetration from the ground into a dwelling. Whereas there is a general perception that water can ingress through the block work structure of the external face of a wall into the property, it is less apparent, but equally possible, that water will penetrate from the ground on the inside of the property. Figures 6.2 and 6.3 illustrate these flow paths for two types of ground floor (ground bearing floor and suspended concrete floor), and different types of foundation (typical for construction in England).  Concrete blocks used in foundations should be sealed with an impermeable material or encased in concrete to prevent water movement from the ground to the wall construction.

Please feel free to contact the office for an informal discussion regarding your requirements.

Finished Floor Levels

ground_floor_parking_floodYou can put less sensitive uses (parking or retail) on the ground floor of your development in order to reduce risk to users from flooding. Similar to the safe refuge principal.

This simplifies flood resilience measures. By example if a parking area is flooded, far less of the material present will be affected by flood water.


Read more on:

Flood Resistant Design - Temporary Refuges - Surface Water Management