Thick coating
Structural waterproofing for basements, foundations and plinths
Thick coating (KMB) – permanent protection against ground moisture
Thick coating – also known as KMB (polymer-modified bitumen thick coating) or PMBC – is the standard solution for structural waterproofing to DIN 18533. It is applied to external basement walls, foundations and earth-contact concrete components, providing permanent protection against ground moisture and non-pressurised water. Unlike liquid waterproofing for balconies, KMB is specifically designed for the load of soil and long-term moisture exposure.
DOBAU®-1KS – single-component
Ready to use directly from the bucket – no mixing required. With polystyrene filler, solvent-free, crack-bridging, to DIN 18533. 12 L bucket for EUR 34.50 (EUR 2.88/l).
To DOBAU®-1KS → Higher performance ★DOBAU®-2KS – two-component
Two-component KMB for higher requirements – faster curing, more robust against rain shortly after application. Solvent-free, to DIN 18533. 15 L bucket for EUR 36.50 (EUR 2.43/l).
To DOBAU®-2KS →1K or 2K – the decision
Single-component or two-component?
| Product | Components | Advantage | Application | Price |
|---|---|---|---|---|
| DOBAU®-1KS | 1K – ready to use | No mixing, immediately ready | Standard waterproofing, basements, foundations | EUR 34.50 / 12 l (EUR 2.88/l) |
| DOBAU®-2KS ★ | 2K – brief mixing | Faster curing, more robust, lower price per litre | Higher requirements, larger areas | EUR 36.50 / 15 l (EUR 2.43/l) |
Correct application of thick coating
How to apply KMB correctly
Prepare substrate and prime
Substrate must be load-bearing, dust-free and free of loose material. Apply bitumen primer V or Duo primer thinly and allow to dry fully. Form a cove fillet at wall-to-floor connections – this transition is the most common weak point.
Apply KMB in two coats
Apply first coat with brush, spatula or airless equipment. Maintain total layer thickness to DIN 18533 (min. 3 mm dry). For 2K system, mix briefly then apply immediately. Second coat in cross direction after sufficient intermediate drying.
Apply protection board and backfill
Before backfilling with soil, apply a protection board or studded membrane – this protects the KMB from mechanical damage by stones and earth pressure. Only backfill after full curing.
How much KMB do I need?
Rule of thumb: 4–6 kg per m² for min. 3 mm dry layer thickness
As a guide: 4–6 kg of KMB per m² for the minimum layer thickness of 3 mm dry (equivalent to approx. 6 mm wet) required by DIN 18533. The 12 L bucket of 1KS covers approximately 2–3 m² of basement wall. For a typical basement wall area of 30 m², 5–6 buckets are needed. The exact quantity depends on substrate roughness and layer thickness.
Frequently asked questions
Frequently asked questions about thick coating
What is KMB and what is it used for?
KMB stands for polymer-modified bitumen thick coating (PMBC). It is the standardised structural waterproofing to DIN 18533 for earth-contact components: external basement walls, foundations, underside of floor slabs and plinth areas. It provides permanent protection against ground moisture and non-pressurised water.
What is the difference between 1K and 2K thick coating?
1K (single-component): ready to use from the bucket, no mixing – simpler for DIY. 2K (two-component): mix base and hardener briefly, then apply. Advantages: faster curing, more robust against rain shortly after application, lower price per litre. The preferred choice for large areas and professionals.
Do I need to prime before KMB?
Yes, always. Apply bitumen primer V or Duo primer on concrete and masonry and allow to dry fully. The primer binds dust, seals pores and significantly improves KMB adhesion. Form a cove fillet at wall-to-floor connections before applying KMB.
Does KMB also protect against pressurised water?
KMB to DIN 18533 protects against ground moisture and non-pressurised water (splash water, rainwater in soil). Against pressurised water (groundwater, flooding), KMB alone is insufficient – a stronger waterproofing solution is required. Please seek professional advice if groundwater is a risk.
How long must KMB dry before backfilling?
Full curing takes several days depending on temperature and humidity. At +15–20°C and normal humidity, KMB is sufficiently cured for backfilling after approx. 3–7 days. Always apply a protection board or studded membrane before backfilling with soil.
Permanently waterproof basements and foundations
Choose the right KMB now.
DOBAU®-1KS for simple application – DOBAU®-2KS for higher performance and lower price per litre.