A retaining wall faces moisture from the ground behind it, so waterproofing and drainage need to be considered together. The membrane must suit the wall substrate and connect across joints, changes of plane and penetrations. Protection during backfilling also matters: damage or an incomplete detail can be difficult to reach once the wall is buried.
On an existing wall, damp patches, salts or seepage can have more than one source. Record where and when the symptoms occur and what drainage or previous repairs are known. Access to the soil side, wall condition and adjoining construction will influence whether a local repair is realistic. Waterseal’s retaining wall waterproofing service describes the application; the structural damp service covers broader moisture investigation.
Waterproofing and drainage work together
A retaining wall can be exposed to moisture from soil and adjoining ground levels. Waterproofing must be considered together with drainage, the construction of the wall, its joints and the materials used to protect the membrane before backfilling. The approach depends on the wall and access to the affected side.
For an existing wall, record seepage, staining, salt deposits and the conditions when moisture appears. Investigation can help distinguish lateral moisture entry from other sources of damp. A repair scope should explain the source-control, preparation and detailing requirements, including any limitations imposed by access.
