PPS 15 Planning and Flood Risk (Revised)·Page 78
Water Resistant Walls
Building structures should use flood-resistant materials in external walls, with preference for engineering bricks, solid walls where appropriate, and water-repellent finishes to reduce water infiltration.
The building structure is designed using flood resistant materials that are able to reduce or stop the infiltration of water through the external walls. Solid walls can be constructed instead of cavity walls. Engineering bricks are preferred to concrete / aircrete bricks as they have lower water absorption rates. External joints and rendering can be designed to be more water repellent. Rigid insulation can be applied to cavity walls and internal walls can use cement based renders with a high lime content. Standard gypsum plasterboard which disintegrates when it becomes wet should be avoided.
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