How to Stop Rising Damp with a Liquid DPM
Where a building meets the ground, moisture wants to move upward through the structure. Without an effective damp proof barrier, that shows up as rising damp — tide marks, salt staining, blown plaster and damaged finishes near the base of walls and across ground floors.
How to spot rising damp
Classic signs are a tide mark up to around a metre above floor level, fluffy white salts on the plaster, peeling paint or paper, crumbling skirtings, and a cold, musty feel low down. It differs from penetrating damp (which comes through walls higher up) and condensation (surface moisture) — the cure depends on getting the diagnosis right.
What the regulations require
Approved Document C (resistance to moisture) requires floors and walls next to the ground to resist moisture passing to the inside. A horizontal damp-proof course (DPC) should sit at least 150mm above external ground level (more where paving could bridge it), and ground floors need a damp-proof membrane (DPM). For habitable below-ground space, BS 8102:2022 sets out the waterproofing design — typically Grade 3 (a dry environment) for living areas.
The solution: a liquid damp proof membrane
Waterproof Blue Liquid DPM is a polymer-modified, liquid-applied membrane that cures to a seamless, flexible barrier on foundations, slabs and walls. Roller-applied for fast coverage, it bridges cracks and bonds tightly to concrete and cement substrates — with no laps or punctures to fail like a loose sheet DPM.
Detail the awkward bits by hand
Use the 5kg brush grade to seal reveals, upstands and junctions accurately, and step up to The GOAT for tanking below-ground structures to BS 8102.
How it is applied
- Prepare a sound, clean substrate
- Detail junctions and upstands with the brush grade
- Roller-apply across floors and walls in the required coats
- It cures to a continuous, seamless waterproof layer
Benefits
- Seamless and crack-bridging — no joints to fail
- Blocks moisture and vapour
- Fast roller application
- Bonds tightly to concrete and cement
Frequently asked questions
Is it the same as waterproofing a basement? Related, but below-ground habitable space follows BS 8102 — see The GOAT for full tanking.
How do I know it’s rising damp and not condensation? See Rising Damp: How to Spot It and Stop It for a clear diagnosis guide.
Browse our liquid waterproof membranes, or get advice on your project.