As its name implies, Lateral Damp occurs when moisture penetrates a substrate horizontally rather than vertically. Typically it occurs where soil backs a wall such as in basements and cellars, soil-retaining walls, split levels etc. Ideally walls subject to lateral damp should be protected on the positive (external) side so that moisture is prevented from entering the substrate.
But where this is not possible – usually because walls were not initially protected or the protection has failed – it is necessary to apply dampproofing to the negative (internal) side of the wall. During construction – where it is possible to treat the positive side of the walls - the following products can be used:
DryBase Liquid Applied DPM
In those areas where there is a high water table, it is advisable, when using torch-on membrane, to use a double layer of protection as overlaps may separate due to the water pressure. Where the negative side of the wall is to be treated, it is not advisable to use torch-on membrane as the treated surface will require either a further brick cover or plasterboard to give the wall a more pleasing finish. The most suitable products are:
SWS Slurry (with Bondaid Plus)
The wall/slab joint should also be re-inforced with Fillet Seal.
In extreme cases, where there is running water on the walls and cement-based products will not cure, a completely different form of treatment may be necessary – see Basements and Cellars
Boundary walls invariably are affected by Damp since by law no dpc sheeting may be fitted. However, in addition such walls are often badly affected by Lateral Damp where ground level between properties is at differing heights. Treatment with SWS or Latseal slurry can prevent the passage of moisture through the walls.
For more information please contact us on 011 708 3603 or 021 982 5131.