Liquid roof waterproofing
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Seamless, no torch, immediately watertight
Liquid roof sealant – brushable instead of torch-applied
Liquid roof sealant is applied by brush, roller or spatula and forms a seamless, elastic sealing layer after curing. No overlaps, no welded seams, no torch – the coating adapts to unevenness, corners and connections by itself. Ideal for repairs, flat roof waterproofing and anywhere a membrane is difficult to install.
DOBAU® Dachelastik
Elastic roof sealing compound on polymer bitumen basis for new and renovation waterproofing. For timber, metal and mineral substrates. Crack-bridging, seamless. 5 kg (EUR 55) or 10 kg (EUR 99).
To Dachelastik → Balcony & terrace ★DOBAU® Plast S
Highly elastic, solvent-free sealant on emulsion basis – can be applied to slightly damp substrates. Ideal for balconies, terraces and flat roofs in renovation. 5 kg (EUR 27.50) or 10 kg (EUR 52.50).
To Plast S → Reinforcement ★Fibreglass fleece
Reinforcement fleece (30 cm × 10 m) for embedding in fresh sealant at corners, edges, connections and pipes. Prevents cracking at stress points. EUR 9.80 / 10 m.
To fibreglass fleece →Dachelastik or Plast S?
Two sealing compounds – the right choice for every substrate
| Product | Basis | Key feature | Typical application | Price from |
|---|---|---|---|---|
| Dachelastik 5 kg ★ | Polymer bitumen | Crack-bridging, seamless, robust | Flat roof new/renovation, timber, metal, concrete | EUR 55.00 (EUR 11.00/kg) |
| Dachelastik 10 kg ★ | Polymer bitumen | Crack-bridging, seamless, robust | Larger roof surfaces, renovation | EUR 99.00 (EUR 9.90/kg) |
| Plast S 5 kg ★ | Emulsion, solvent-free | Also workable on slightly damp substrates | Balcony, terrace, flat roof, renovation | EUR 27.50 (EUR 5.50/kg) |
| Plast S 10 kg ★ | Emulsion, solvent-free | Also workable on slightly damp substrates | Larger balcony/terrace areas | EUR 52.50 (EUR 5.25/kg) |
| Fibreglass fleece ★ | Fibreglass, 30 cm × 10 m | Reinforcement for stress points | Corners, edges, connections, pipes – always recommended | EUR 9.80 (EUR 0.98/m) |
Application in three steps
How liquid roof sealant is applied
Prepare the substrate and prime
Substrate clean and free of dust and loose material. For absorbent substrates (concrete, masonry), apply bitumen primer first. For non-absorbent surfaces (metal, sheet metal), check adhesion – sand if necessary.
First coat + embed fleece
Apply first coat. While still fresh: press fibreglass fleece into corners, edges, connections and pipes – the fleece prevents cracking at these stress points. Overcoat with a second layer.
Second or third coat, allow to cure
After the first coat has dried, apply a second (and for Plast S possibly third) coat. Maintain the total layer thickness specified by the manufacturer. Allow full curing before rain or load.
When liquid sealant, when membrane?
Membrane for large areas – liquid for details and repairs
For large, level flat roof areas, the KSK membrane is faster and more economical. Liquid roof sealant comes into its own for repairs on existing roofs where a membrane is hard to install, for complex geometries with many connections and penetrations, and for balconies and terraces that need to be walkable or receive a covering. Both systems can also be combined: membrane for the main area, liquid for connections.
Frequently asked questions
Frequently asked questions about liquid roof sealant
What is the difference between Dachelastik and Plast S?
DOBAU® Dachelastik is on a polymer bitumen basis – more robust, for roof surfaces in new construction and renovation on timber, metal and mineral substrates. DOBAU® Plast S is solvent-free on an emulsion basis and can be applied to slightly damp substrates – ideal for balconies, terraces and renovation surfaces that cannot dry out completely.
Why is the fibreglass fleece needed?
The reinforcement fleece is embedded in fresh sealant at corners, edges, connections, pipe penetrations and other stress points. Mechanical stresses at these points can otherwise cause cracks in the coating. The fleece bridges these points permanently.
How much Dachelastik or Plast S do I need?
As a rough guide: approximately 1–1.5 kg per m² per coat depending on the substrate. For two coats, 2–3 kg/m². For 10 m² of roof surface, approximately 20–30 kg in total. The 10 kg bucket is usually the more economical choice. Please contact us for precise quantity planning.
Can Plast S be applied to a damp substrate?
DOBAU® Plast S can be applied to slightly damp substrates – a significant advantage over solvent-based products. However, it should not be applied to truly wet surfaces or those covered with water. The surface should be no more than slightly damp, not wet.
How long does curing take?
Depending on layer thickness, temperature and humidity – under normal conditions the first coat is dry enough for the second coat after a few hours. Full curing after 24–48 hours. Minimum processing temperature: +5 °C.
Seal roof, balcony or terrace seamlessly
Choose the right product now.
Dachelastik for roof surfaces – Plast S for balconies and terraces – fleece for corners and connections.