Description
Old felt starting to blister, a GRP roof weeping at the joints, or a run of flashing that's given up before the rest of the roof has?
A brush-applied liquid rubber coating is often the fastest way back to watertight, without stripping the existing roof covering back to deck.
This is a water-based, cold-applied liquid rubber membrane that goes on by brush, roller or airless sprayer straight over sound felt, asphalt, GRP, concrete, masonry, metal and timber, curing to a flexible, seamless, fully bonded rubber skin with no seams or laps for water to find.
Key benefits
- Cold-applied — no blowtorches, hot bitumen or specialist welding equipment needed
- Forms a seamless, fully bonded elastomeric membrane with no joints or seams
- Water-based formula: low odour, solvent-free, safe for use in occupied buildings
- Stays flexible through UK freeze-thaw cycles rather than cracking like old bituminous paint
- Brush, roller or spray-applied — suited to detail work and larger open areas alike
Suitable applications
Refurbishing worn felt, asphalt and GRP flat roofs; sealing failing box gutters, parapet details and chimney flashings; treating balconies, decks and planter boxes; general above-ground waterproofing on concrete, masonry, timber and metal.
On EPDM rubber roofs it's most useful as a detail-repair coating around upstands, pipe penetrations and old patch repairs rather than as a substitute for a proper EPDM membrane on the main roof field — for new EPDM installations, see our EPDM membrane range instead.
This is the black waterproofing coating — the product for sealing and re-waterproofing.
If your roof is already watertight and the problem is summer heat and UV ageing, our white Solar Reflective Roof Coating is the reflective topcoat for that job, and the two are often used together: waterproof first with this, then reflect the heat with the white topcoat.
Specification
| Size | Colour | Coverage (2-coat system) | Application | Cure |
|---|---|---|---|---|
| 3.78 litres | Black | ~1.9–2.5m² per coat | Brush, roller or spray | Touch dry within hours, full cure over several days |
| 18.9 litres | Black | ~9.3–12.5m² per coat | Brush, roller or spray | Touch dry within hours, full cure over several days |
Coverage is a guide for a standard two-coat application and will vary with substrate porosity and application method — always apply a small test area first on porous or previously coated substrates.
Installation & ordering guidance
Surfaces must be clean, dry and free of loose material before coating — our EPDM Weathered Membrane Cleaner is a good option for degreasing and preparing old membrane or flashing details before recoating.
For detail work around upstands and penetrations where a belt-and-braces seal is wanted, our EPDM Lap Sealant and EPDM Rubber Roof Primer pair well as a finishing detail.
Order the 3.78L size for small repairs, balconies and detail work, and the 18.9L size for full roof refurbishment — as a guide, one 18.9L tub covers a two-coat system across a roughly 9–12m² roof, so measure your roof area and add a margin for detail work and a second coat before ordering.
FAQs
Can I apply this directly over old roofing felt or asphalt?
Yes, provided the surface is sound, clean and free of standing water or loose material — this is one of its main uses, refurbishing tired felt and asphalt roofs without a full strip-back.
How many coats do I need?
A minimum two-coat system is recommended for a fully waterproof result; the coverage figures above assume two coats.
Is it compatible with EPDM rubber roofing?
It bonds well to EPDM for detail and repair work (patches, upstand dressing, old repair touch-ups), but it isn't a substitute for a bonded EPDM membrane across a full roof field — use it as a repair/refurbishment coating rather than a primary EPDM system.
Which size do I need for my roof?
Measure the area to be coated in m², then choose the tub that comfortably covers a two-coat application with some margin — see the coverage table above.
For larger commercial areas, order multiple 18.9L tubs.
How is it delivered and how long does it take?
Both sizes are dispatched from UK stock on a standard tail-lift/parcel delivery service; typical UK mainland delivery is 2–5 working days from order.
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