Primers & Undercoats
The first step before any waterproofing
Primers – adhesion that lasts for years
Every waterproofing system is only as good as its adhesion to the substrate. Concrete, masonry and screed are porous and dusty – without primer the adhesive is drawn into the pores and bonds to loose dust particles rather than to the surface itself. With the right primer, pores are sealed, dust is bound and a chemical bonding bridge is formed. The result: the waterproofing holds permanently – even under moisture load and mechanical stress.
Bitumen primer V – solvent-based
Thin-bodied, penetrates deeply into concrete and masonry. Before KSK membranes, liquid waterproofing and thick coatings. 1 L from EUR 7.50, 10 L from EUR 39.90 (EUR 3.99/l).
To bitumen primer V → Low-VOC, lower odourDOBAU® Duo primer
Low-VOC bitumen emulsion with duo technology – for KSK membranes and roof coverings. Less solvent odour, good for interiors and confined situations. 5 kg (EUR 21.90), 10 kg (EUR 29.80).
To Duo primer → Before bitumen tapesUniversal bonding primer
Transparent plastic primer specifically for bitumen tapes (aluminium tape, flex sealing tape) on mineral substrates. Binds dust, consolidates pores. 0.5 L from EUR 7.90.
To universal bonding primer →Which primer for which waterproofing product?
All products and applications at a glance
| Product | Type | Use before | Price from |
|---|---|---|---|
| Primer V 1 L | Solvent-based | Liquid waterproofing, thick coating, KSK membranes | EUR 7.50 |
| Primer V 5 L | Solvent-based | Medium areas – balcony, terrace, flat roof | EUR 26.90 (EUR 5.38/l) |
| Primer V 10 L | Solvent-based | Large areas – basement, roof surface | EUR 39.90 (EUR 3.99/l) |
| Duo primer 5 kg | Low-VOC, emulsion | KSK membranes, roof coverings – eco choice | EUR 21.90 (EUR 4.38/kg) |
| Duo primer 10 kg | Low-VOC, emulsion | Large areas – lowest price per kg | EUR 29.80 (EUR 2.98/kg) |
| Universal bonding primer 0.5 l | Plastic primer, transparent | Bitumen tapes on concrete, stone, masonry | EUR 7.90 |
| Universal bonding primer 1 l | Plastic primer, transparent | Larger areas with bitumen tapes | EUR 14.80 |
| Universal bonding primer 2.5 l | Plastic primer, transparent | Many connections and tapes on one site | EUR 33.90 |
What primer does on different substrates
Three effects – one product
Seal pores
Concrete, screed and masonry are porous substrates. Without primer, waterproofing compound is drawn into the pores and is no longer available for adhesion. Primer seals the pores and creates a uniform, receptive surface.
Bind dust
Every concrete surface has a layer of loose dust and cement laitance. Bonding directly on top means the waterproofing only adheres to the dust – not to the concrete. Primer penetrates and permanently binds this dust.
Create a bonding bridge
Primer creates a chemical bond between the substrate and the waterproofing. Adhesion on primed substrates is measurably higher – particularly important for waterproofing against moisture and in earth-contact applications.
Primer V or Duo primer?
Solvent-based penetrates deeper – low-VOC smells less
Primer V penetrates deeply into old and rough substrates thanks to the solvent content – ideal for very absorbent or weathered surfaces and wherever maximum penetration depth is needed. It dries quickly but has a solvent odour. Duo primer is low-VOC and lower-odour – the better choice for work in confined spaces, with poor ventilation or when occupants are in the building. For normal substrates, both are equally effective.
Frequently asked questions
Frequently asked questions about primers
Do I always need to prime before liquid waterproofing?
On absorbent substrates such as concrete, screed and masonry, priming should always be done – adhesion of the liquid waterproofing is significantly better and more durable after priming. On non-absorbent surfaces (metal, sheet metal, tiles), no classic primer is needed, but surface preparation (sanding, degreasing) is required.
Which primer before thick coating (KMB)?
Use Primer V or Duo primer before bitumen thick coating (KMB) – not universal bonding primer, which is only for tapes. On very absorbent basement walls prefer Primer V – it penetrates more deeply. The primer must be dry and slightly tacky before KMB application.
What is the difference between universal bonding primer and Primer V?
Universal bonding primer is a transparent plastic primer specifically for bitumen tapes on mineral substrates – it binds dust and consolidates pores. Primer V is a bitumen primer for surfaces that will subsequently receive membranes or coatings (liquid waterproofing, thick coating).
How long must you wait after applying primer?
Primer V is fast-drying: under normal conditions (+15–20°C) ready to use after 30–60 minutes. The primer should be dry and slightly tacky – no longer wet but still slightly tactile. Duo primer dries somewhat slower on an emulsion basis.
How much primer do I need per m²?
As a guide: 0.2–0.4 L per m² depending on substrate absorbency. Very absorbent substrates (old concrete, calcium silicate blocks) need more. Apply thinly and evenly by brush, roller or spray.
The first step to lasting waterproofing
Choose the right primer now.
Primer V for membranes and coatings – Duo primer low-VOC – universal bonding primer for bitumen tapes.