Damp proofing

Damp proofing

Damp proofing in construction is a type of waterproofing applied to building foundation walls to prevent moisture from passing through the walls into interior spaces. Damp problems are one of the most frequent problems encountered in homes.

A complete survey by one of our trained surveyors, aided by an electronic moisture meter, will determine the extent and causes of the damp problem.

A complete and proper recommendation is only given after a thorough investigation.

We have treated all types of damp professionally for the past 10 years.

Rising Damp

Rising damp in buildings may be defined as the vertical flow of water up through a permeable wall structure or floor, the water being derived from ground water. The water rises through the pores (capillaries) in the masonry or concrete by a process loosely termed “capilliarity.” In other words the masonry acts like a wick.
The treatment method will depend on whether the rising damp is affecting a solid floor, or is rising up a wall (as shown on the photograph).

Treatment of Rising Damp in solid floors:

This happens most regularly where developers have failed to fit dpc sheeting beneath the slab or when an existing dpc has failed. Several new products are now available to stop Damp rising through floor slabs, notably ECS Epoxy Floor Coating and Dry Base Vapour Membrane. Where the floor slab is contaminated (e.g. oil stains or bitumen) or hydrostatic water pressure is excessive it may be necessary to lay CDM Industrial Membrane over the slab after which a new screed or wooden flooring can be fitted over the membrane.

Treatment of Rising Damp in walls:

Dryzone damp-proofing cream, or Microsilan DPC fluid is injected into the wall at floor level to provide an impermeable barrier, preventing the damp rising up the wall. Affected plaster is removed and replaced with a plaster applied to the specification given in our Renderguard Gold data sheet.

What is Lateral

Lateral damp is when moisture is allowed to enter the structure in a horizontal direction. Gravity then causes the downward movement of the damp into other areas. Penetrating damp can create isolated patches of dampness that increase in size after periods of heavy rain. The damp can occur at any level, unlike Rising Damp which usually rises from the ground up to 1.2 metres high. Lateral or penetrating damp is usually from a source too difficult to control and only an expert with a moisture metre detector will evaluate the difference in rising and lateral damp. Sometimes the problem may also require a plumber to pressure test the pipes to eliminate them as the problem.

Causes of Lateral Damp

  • Leaking water supplies or waste pipes
  • fretted mortar joints
  • defective brickwork
  • failure of tile grouts in showers and other wet areas
  • poorly functioning membrane in wet areas
  • cracked render
  • poor flashings
  • defect in adjacent property outside the owners control
  • air-conditioning or hot water system overflows can also lead  to small localised patches of dampness.

All Damp proofing work carries a guarantee.

DAMP PROOFING