Waterproofing keeps liquid water out of the building envelope — roofs, balconies, retaining walls, below-ground areas. Damp-proofing deals with moisture moving through materials: a damp-proof course (DPC) in a wall or a damp-proof membrane (DPM) under a floor that stops ground moisture rising into the structure.
Getting the two confused wastes money. A coating over rising damp traps moisture and makes it worse; a DPC does nothing for water being pushed through a retaining wall under pressure. We identify which problem you actually have before recommending a treatment.
Rising damp shows as a tide mark low on interior walls, blistered paint, salt deposits and a musty smell, and it stays damp even in dry weather. It usually means the damp-proof course has failed or was bridged — often by garden soil, a paved path or a flower bed built up against the wall.
Treatment depends on the cause: lowering soil levels and improving drainage where the DPC is simply bridged, or installing a remedial damp-proof course where it has failed, followed by replacing salt-contaminated plaster. We explain what we will treat and what still needs a builder or landscaper.
A retaining wall holds back soil, and soil holds water. Without waterproofing and drainage on the retaining side, water builds up and pushes through to the exposed face, staining and eroding the finish and, over time, loading the wall.
Where it can be accessed, we waterproof the retaining (soil) side and make sure sub-soil drainage carries water away, rather than only painting the visible face. On foundation walls we treat penetrating damp where moisture is moving through the masonry near ground level.
Below-ground walls and basements face hydrostatic pressure — standing groundwater pushing against the structure — which is a different problem from surface damp. The ideal is positive-side waterproofing applied to the outside face during construction; on existing homes that is not always accessible, so a suitable negative-side or cementitious system may be used instead.
Below-ground waterproofing is specialised and site-specific. We assess what is realistically achievable on your home and are clear about the limits before quoting, rather than promising a dry basement we cannot guarantee.
Tide marks low on a wall, bubbling or flaking paint near the floor, white salt crystals (efflorescence), a persistent musty smell, damp patches on a retaining wall after rain, or a basement that smells or feels wet — these point to damp or below-ground water rather than a roof leak.
The earlier damp is traced, the cheaper it is to fix: left alone it rots skirtings, lifts finishes and damages plaster across a whole wall.