To seal an asbestos roof, sterilise it with Biocide and leave it on, then encapsulate it with two coats of Asbestos Fiber Lock — without scrubbing, pressure-blasting or otherwise disturbing the sheets. Sealing an asbestos roof this way locks the fibres in and weatherproofs it, keeping the roof in service safely.
How to clean an asbestos roof before painting
Clean an asbestos roof gently — never with a pressure washer or wire brush. Apply Biocide to kill moss, lichen and algae, and leave it on the roof to keep working; do not rinse it off. Aggressive cleaning releases asbestos fibres, so the biocide does the work instead of scrubbing.
The steps to seal an asbestos roof
- Sterilise. Treat the whole roof with Biocide and let it work; leave it on.
- Check the sheets. Confirm they are sound. Broken or friable sheets need a licensed removal contractor, not sealing.
- First encapsulation coat. Apply Asbestos Fiber Lock gently by brush, roller or spray, working the coating into the surface.
- Second coat. Apply the second Fiber Lock coat once the first has dried to build the full encapsulating film.
- Colour coat (optional). Finish with a UV-stable Premium Roof & Wall for the colour you want.
How much Fiber Lock you need
Old asbestos cement is porous, so it absorbs the first coat and uses more product than a smooth roof. Budget for two full coats over the whole area and confirm the spread rate on the product data sheet. The first coat consolidates the surface; the second builds the seal.
How long does a sealed asbestos roof last?
A properly encapsulated asbestos roof stays sealed and weatherproof for years, and is refreshed with a maintenance coat before the film weathers through. Inspect it yearly, treat any new moss, and recoat the topcoat when the colour fades — the encapsulation keeps working underneath.
Working safely on the roof
Do not walk directly on asbestos sheets — use roof ladders and crawl boards to spread your weight. Do not cut, drill or sand the sheets, and keep the coating wet-on to avoid dust.
Why seal instead of remove
Sealing an intact asbestos roof avoids the cost, disruption and fibre risk of removal while giving the roof years more service and a weatherproof, colour-coated finish. Removal is reserved for sheets that are already broken or crumbling.
Frequently asked questions
How do you clean an asbestos roof before painting? Gently — apply Biocide to kill growth and leave it on. Never pressure-blast or wire-brush asbestos.
Can you seal an asbestos roof yourself? Yes on sound sheets, if you never disturb them — sterilise with Biocide, then encapsulate with Asbestos Fiber Lock. Damaged sheets need a licensed contractor.
How long does a sealed asbestos roof last? Years, with a maintenance coat before the film weathers through. Inspect yearly and recoat when the colour fades.
Where to buy
Shop Biocide and Asbestos Fiber Lock, or read the complete roof paint guide. Trade pricing: +27 84 985 6141.
