Damp Proofing

Yet again Maclennan-LSE have been asked to comment on damp in a cob wall,  where lime mortar has been recommended. The wall is earth retaining and lime mortar in this situation would not be suitable. Even though we sell and apply lime mortars we would never apply it to a very damp wall let alone an earth retaining wall.

In old buildings, walls were built to such a thickness that normally damp would not penetrate to the inside. The joints were always of lime mortar or earth and were more porous than the building’s structural elements comprising brick, stone etc. Consequently the joints would drain and shed water by evaporation, therefore not allowing damage to these structural elements. The joints were the sacrificial element of the building.

The remedies employed to protect the walls were often ineffective or unsightly. The more effective remedies were slate/tile hanging or Mathematical tiling on battens. However, they do not suit every house or every situation.

Sand cement render was used in most situations from 1900 onwards. Cement render invariably cracks allowing rain water in and compounding the problem.

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