Liquid waterproofing
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Seamless and without a torch
Liquid waterproofing – brushable, seamless, for roofs, balconies and wet rooms
Liquid waterproofing is applied by brush, roller or spatula and forms a seamless, elastic waterproofing layer after curing with no overlaps and no torch. It is particularly suited to areas with complex geometry, many connections and penetrations, renovation of existing surfaces and anywhere a membrane is difficult to install. Two systems are available: Dachelastik for roof surfaces on dry substrates, Plast S for balconies and terraces even on slightly damp substrates.
DOBAU® Dachelastik
Elastic roof waterproofing compound on polymer bitumen basis. Seamless, crack-bridging, for timber, metal and mineral substrates. 5 kg (EUR 55.00) / 10 kg (EUR 99.00, EUR 9.90/kg).
To Dachelastik → Balcony & terrace ★DOBAU® Plast S
Solvent-free, highly elastic waterproofing on emulsion basis – also on slightly damp substrates. For balconies, terraces and flat roofs. 5 kg (EUR 27.50) / 10 kg (EUR 52.50, EUR 5.25/kg).
To Plast S → Reinforcement – always recommendedFibreglass fleece
Reinforcement fleece 30 cm × 10 m for embedding in fresh waterproofing compound at corners, edges, pipes and connections. EUR 9.80 / 10 m (EUR 0.98/m).
To fibreglass fleece →Dachelastik or Plast S?
All products compared
| Product | Basis | Application | Key feature | Price |
|---|---|---|---|---|
| Dachelastik 5 kg | Polymer bitumen | Roof surfaces, new + renovation | On timber, metal, mineral | EUR 55.00 (EUR 11.00/kg) |
| Dachelastik 10 kg | Polymer bitumen | Larger roof surfaces | Lower price per kg | EUR 99.00 (EUR 9.90/kg) |
| Plast S 5 kg ★ | Emulsion, solvent-free | Balcony, terrace, flat roof | Also on slightly damp substrates | EUR 27.50 (EUR 5.50/kg) |
| Plast S 10 kg ★ | Emulsion, solvent-free | Larger balcony/terrace areas | Lowest price per kg in the range | EUR 52.50 (EUR 5.25/kg) |
| Fibreglass fleece | Fibreglass, 30 × 10 m | Corners, edges, connections, pipes | Prevents cracking at stress points | EUR 9.80 (EUR 0.98/m) |
Application step by step
How to apply liquid waterproofing correctly
Prepare the substrate
Remove dust, loose dirt and friable material. On highly absorbent substrates (concrete, screed) apply primer first. Fill cracks and deep voids beforehand.
First coat + fleece at connections
Apply first coat. While still fresh: press fibreglass fleece into corners, edges, pipes and wall connections and overcoat with second layer. The fleece prevents cracking at these stress points.
Second coat and cure
After the first coat has dried, apply the second coat in the cross direction. Maintain total layer thickness per manufacturer specification. Protect from rain and foot traffic until fully cured (24–48 hours, temperature-dependent).
How much liquid waterproofing do I need?
Rule of thumb: 1–1.5 kg per m² per coat
As a rough guide: approximately 1 to 1.5 kg per m² per application depending on substrate and layer thickness. For two coats: 2–3 kg/m². For a 10 m² balcony, 20–30 kg is needed – the 10 kg bucket is then the more economical choice. Please contact us for precise quantity calculations or for unusual substrates.
Frequently asked questions
Frequently asked questions about liquid waterproofing
Dachelastik or Plast S – what is the difference?
Dachelastik is based on polymer bitumen and is suitable for roof surfaces on dry substrates – on timber, metal and mineral surfaces. Plast S is solvent-free on an emulsion basis and can be applied to slightly damp substrates – ideal for balconies and terraces that could not be fully dried before coating.
Why is the fibreglass fleece needed?
The fleece is embedded in fresh waterproofing compound at corners, edges, pipe penetrations and wall connections. Mechanical stresses at these points can otherwise cause cracking in the cured layer. The fleece bridges these points permanently.
Can liquid waterproofing be applied to old screed or tiled surfaces?
Yes – provided the substrate is load-bearing and free of loose material, and tile adhesive is still bonded. Fill joints between tiles and cracks beforehand. Prime highly absorbent old screed, then apply liquid waterproofing in two coats.
Can Plast S be walked on or tiled over after curing?
Yes – walkable and ready for tiling after at least 48 hours of curing (tiles, gratings, slab coverings). Check compatibility between the waterproofing and tile adhesive mortar.
How long does curing take?
First coat ready for second at +15–20°C after 4–8 hours. Full curing 24–48 hours. Minimum application temperature +5°C.
Permanently waterproof roofs, balconies and terraces
Choose the right system now.
Dachelastik for roof surfaces – Plast S for balconies and terraces – fibreglass fleece for corners and connections.