Mould & dark patches
Damp areas of wall become a breeding ground for mould. Black spots, a musty smell, airborne spores — leading to respiratory problems and allergies.
foundation
Basement-wall waterproofing
Basement-wall waterproofing
with liquid rubber against damp & ground water
Elastic interior coating for damp basement walls. Stops mould growth, protects the building fabric and stays vapour-permeable — the masonry can keep breathing while water is reliably blocked.
summarize
At a glance
Basement waterproofing with liquid rubber gives reliable protection against rising damp, ground water and efflorescence — inside or outside. The elastic membrane bridges fine settlement cracks and stays breathable, so moisture in the wall can still escape. Applied cold in 2 coats, with no torch work and no harsh-smelling solvents.
When the basement gets damp
Damp basement walls aren't a cosmetic problem — they destroy building fabric, encourage mould and endanger occupants' health. The longer you wait, the more expensive the refurbishment.
Salt efflorescence
White crystalline deposits on the wall signal rising damp. The salts spall the render from the inside — classic paints get pushed off under the pressure.
Musty smell + health risk
Even without visible mould, lasting moisture changes indoor air quality. Occupants report headaches and difficulty concentrating — the basement goes unused, property value drops.
Why liquid rubber for basement walls
Vapour-permeable — wall breathes
Water vapour can pass from the inside out, while liquid water is blocked. No moisture trapped behind the coating, no blistering.
Salt-tolerant
Holds up against the pressure of salt efflorescence. Unlike emulsion paints, the elastic membrane will not lift off when salts push out through the masonry.
Highly elastic (crack-bridging)
Follows settlement cracks without splitting. The waterproofing stays intact even with small movements in the masonry.
Mould-inhibiting
Water-based with fungicidal additives — offers no foothold for mould. The closed surface can be wiped down whenever needed.
Step-by-step guide
Step 01
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05
Prepare the substrate
Remove loose spots without compromise.
Mechanically remove loose and spalled render — down to sound masonry. Fill out with concrete repair mortar or renovation plaster, let cure for 7 days. The wall must be sound, clean and dust-free before further treatment.
With massive damage (> 5 % of the area) consult a masonry specialist — interior coating alone won't be enough here.
Pro tip: Apply a salt-blocking primer before filling — prevents rising salts from later blasting the repair apart.
Step 02
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05
Treat salts & mould
The invisible brake.
Brush salt crystals off dry — never wash, because water only dissolves the salts briefly and they come back. Then apply a salt-blocking primer to stop migration. With mould: use a commercial mould remover, let act for 24 h, rinse thoroughly, dry for 48 h.
Wall moisture must be below 4 % before further treatment — at higher moisture fix the cause first.
Pro tip: Mould is a symptom, not a cause — find the moisture source (condensation, leaky wall, missing drainage) and fix that first, otherwise mould returns.
Step 03
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05
Prime if substrate is damp
Hydrophobising deep primer.
On strongly absorbent or damp substrate apply a hydrophobising deep primer. This stabilises the render and improves coating adhesion. Let dry for 12 h before further work.
On stable, dry substrate primer can be skipped — proceed directly to Step 4.
Pro tip: In basements with condensation problems, dry with a building dehumidifier for 1–2 weeks before starting — otherwise residual moisture keeps working under the coating.
Step 04
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05
First coat — base barrier
Dilute with 5 % water.
Work in the first coat generously with brush or lambswool roller — slightly diluted with up to 5 % water for deep penetration. Consumption 150–200 g/m². At settlement cracks or wall-to-floor transitions, embed reinforcement fleece (60 g/m²) into the wet coat and roll flush with a press roller.
Go over corners and connections multiple times — the fleece must be fully saturated.
Pro tip: In damp corners first pull a narrow concrete fillet, then reinforce with fleece — water then runs off instead of collecting in the corner.
Step 05
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05
Second coat — armour
Undiluted, full coverage.
After 6–8 h drying apply the second coat undiluted. Consumption 100–150 g/m². Cured and safe against rising damp after 28 days. Until then, ventilate the room with low humidity — a building dehumidifier is recommended.
Against pressurised water (groundwater, hillside) interior coating alone is not enough — additional exterior waterproofing required.
Pro tip: In intensively used basement rooms a third coat is recommended — nearly doubles service life and provides extra reserve against micro-cracks.
lightbulb
Pro tip
Against pressurised water (groundwater, hillside positions) interior coating alone is not enough — exterior waterproofing is also required. Interior coating with RubberPaint works reliably against diffuse moisture, condensation and light ingress.
Technical data
Consumption per coat
150–200 g/m² (absorbent masonry)
Recommended coats
2 (3 with salt efflorescence)
Drying time
2 h dust-dry · 4 h recoatable
Full cure
28 days
Application temperature
+10 °C to +25 °C
Service temperature
−20 °C to +50 °C
Vapour permeability
V2 to EN 1062-1
Elasticity
highly elastic (Class A0/C0 to EN 1062-1)
Max. wall moisture at application
≤ 4 %
Binder
Acrylic latex (solvent-free, low odour)
Tool cleaning
Water, immediately after application
How much material do I need?
Enter your area and desired number of coats — we recommend the optimum tub combination.
m²
Standard: 2 coats. 3 for heavily exposed surfaces.
info
Consumption: 200 g/m² per coat. +10 % buffer for offcuts and uneven surfaces. For larger projects (> 80 m²) contact us for individual advice.
Recommendation
6,6 kg
needed
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06 / Bestsellers
Recommended colours for basement walls
Light shades make the most of the available light in a basement — white is the standard for habitable rooms, with grey and graphite for hobby and workshop areas. Reserve black for plinth zones.
Bestsellers
Sale
Sale
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Sale
Liquid Rubber Paint White RAL 9003
from £22.00
£69.00
incl. VAT, excl. shipping
Liquid Rubber Paint Grey RAL 7046
from £22.00
£69.00
incl. VAT, excl. shipping
Liquid Rubber Paint Graphite RAL 7024
from £22.00
£69.00
incl. VAT, excl. shipping
Liquid Rubber Paint Beige RAL 1015
from £22.00
£69.00
incl. VAT, excl. shipping
Liquid Rubber Paint Black RAL 9005
from £22.00
£69.00
incl. VAT, excl. shipping
Basement Wall Waterproofing — Inside & Outside
Damp basement? External waterproofing with liquid rubber / liquid rubber paint protects the masonry from ground moisture for the long term. A cold-applied protective layer replaces laborious waterproof slurry systems.
Why internal waterproofing isn't enough
- Moisture pushes in from outside — internal barriers trap water in the masonry, followed by mould and efflorescence
- Mineral waterproof slurries crack with the thermal movement of the plinth
- Bitumen coating on its own becomes brittle after a few years
- Pressing water needs a separate solution (German standard DIN 18533-3) — liquid rubber is suitable for ground moisture and non-pressing seepage water
Elastic external waterproofing
Liquid rubber (also called rubber paint, rubberised paint or flexible coating) bonds to concrete, masonry and render. It stays elastic and bridges fine cracks. A 2-coat application with reinforcing fleece at the wall-footing junction creates a seamless barrier against ground moisture.
Step by step
- Excavate. Expose the masonry down to the base of the foundation. Remove the soil so the wall is fully accessible.
- Clean and prepare. Clear soil and old loose coatings from the wall. Fill cracks larger than 3 mm. On absorbent concrete, apply a penetrating primer.
- First coat + reinforcement. Thin with 0–5 % water. At the wall-footing junction (cove fillet), embed reinforcing fleece and saturate it with liquid rubber.
- Second coat. Undiluted, over the whole area. Thickness approx. 0.3 mm dry film = approx. 200 g/m².
- Protect and backfill. After full curing (28 days), place a drainage board or dimpled membrane against the wall. Only then backfill.
Pro tip.
For deep excavations, add a drainage system (filter gravel + drainage pipe). Liquid rubber alone is not enough against pressing water where the water table is very high.
How much do you need?
For 2 coats on absorbent concrete: 0.4–0.5 kg/m². For a 40 m² basement wall ≈ 18 kg (1 × 6 kg + 3 × 3.5 kg plus reserve).
Which colour?
Below ground the colour is invisible. We recommend Black (RAL 9005) as the neutral standard.
Common mistakes to avoid
- Internal waterproofing as the only solution — it just moves the problem
- Pressing water without drainage — liquid rubber is not designed for water pressure
- Backfilling before full curing (28 days) — the coating gets damaged
- No cove fillet and no reinforcement — the wall-footing junction stays weak
FAQ
Does liquid rubber meet the DIN standard?
For ground moisture and non-pressing water (German standard DIN 18533-1, water exposure class W1.1-E), yes. Pressing water has to be planned separately.
How deep do I need to dig?
Down to the base of the foundation — approx. 1.5–2.5 m for a typical detached house.
Can I go over an old bitumen coating?
If the old coating is firmly bonded, yes, after thorough cleaning. Remove any loose areas.
When can I backfill?
28 days after the last coat, with a protective or drainage board in front of the wall.
Ready to start? Choose your colour and tub size.
Go to the shop → · Application overview · FAQ
Related terms: Our product is sold in DIY stores and the trade under several names — liquid rubber, liquid rubber paint, liquid membrane, rubber paint, rubberised paint, flexible coating, elastic exterior paint or polymer coating. They all mean the same product: a waterproof, highly elastic coating based on acrylic latex.
FAQ — basement-wall waterproofing
- Internal or external tanking — which is better?
- Exterior waterproofing is the best solution in building-physics terms, but structurally demanding (excavation). Interior waterproofing with RubberPaint works reliably against diffuse moisture and light ingress. Against strongly pressurised groundwater, exterior waterproofing is mandatory — interior waterproofing alone is not enough.
- Can I apply it to a damp wall?
- No — the wall must have a residual moisture of ≤ 4 % before application. With heavy saturation, fix the cause first (drainage, external crack repair) and let the wall dry for 4–6 weeks. RubberPaint on a wet wall leads to adhesion problems and bubbles.
- What do I do about salt efflorescence?
- Brush salt crystals off dry (do not wash — water only dissolves the salts briefly, they come back). Then apply a salt-blocking primer to stop migration. Only then apply RubberPaint. With massive salt efflorescence, use three coats instead of two.
- Can I paint over the tanking afterwards?
- Yes — RubberPaint is overpaintable. After 28 days of curing you can apply an opaque wall paint (dispersion, silicate) as a finish. Test on an inconspicuous spot recommended to check compatibility.
- Does the product smell unpleasant indoors?
- No — RubberPaint is water-based, solvent-free and low-odour. A light residual odour during drying disappears completely after 24 h of ventilation. Suitable for inhabited basements where people spend time regularly.
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Also suitable for other substrates
The same elastic liquid-rubber coating for many more applications — explore all use cases.
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Got a technical question?
Our technical team advises on complex applications, substrate analysis and film-thickness calculation.