Painted & liquid flat roof repairs

The systems we use

Acrypol+ (acrylic). Single-component, water-based, brush or roller application. Excellent for sound felt or asphalt roofs that just need refreshing. 5–10 year working life. The most economical of the liquid systems.

Cromar Pro Liquid (polyurethane). Two-pack polyurethane with reinforcing fleece. Significantly more durable than acrylic — 15–20 year working life. Bonds to almost any sound substrate. Our default for serious refurbishment work.

Kemperol (polyester/polyurethane). Premium liquid system, fleece-reinforced, used on commercial and listed-building work. Probably the best liquid system on the market. 25-year working life. BBA certified. Cost reflects performance.

Bauder Liquitec. Bauder's polyurethane liquid system, similar to Kemperol in performance. Particularly good for hot-applied details on commercial work.

When liquid is NOT the answer

We won't suggest a liquid repair when:

• The roof has standing water that doesn't drain — liquid systems need a clean, dry substrate to bond properly, and persistent ponding will eventually defeat any waterproofing;
• There's trapped moisture in the existing build-up — sealing this in causes blistering and accelerated deterioration;
• The existing covering is loose, lifting or no longer bonded to the deck — you'd be coating over an unstable substrate.

In those situations, a strip-and-replace or a proper overlay with a new membrane sheet is the right answer. We'll tell you so honestly even though it's a much bigger job for us than a liquid coating would be.

The application process

A typical liquid coating job on a 25m² flat roof runs over one to two days:

• Surface preparation: Clean the existing roof thoroughly — removal of moss, leaves, debris. Treatment of any biological growth with biocide. Repair of any localised failures (small splits patched first). Spot-priming where needed.
• Reinforcing layer: First coat of liquid system applied, into which non-woven fleece is bedded across the full roof area. Particular attention to upstands and detail areas.
• Topcoat: Second coat of liquid system applied over the cured reinforcing layer, in light grey or dark grey finish.

Cure times depend on temperature and humidity. Most jobs are walkable within 4–8 hours of topcoat, fully cured in 24–48 hours.

Warranty

Workmanship guarantee 10 years on Kemperol and Cromar Pro systems, 5 years on Acrypol. Manufacturer warranties on the products themselves match the working life figures quoted above.

What's the lifespan?

The honest answer is "less than a brand-new EPDM or GRP roof, more than another patch repair on the same failing surface." A Cromar Pro liquid system over a tired but sound felt roof will commonly add 15+ years of waterproof life to the building for around half the cost of a full re-roof. Whether that's the right answer depends on how long you intend to own the property, what the access costs are next time, and whether you'd rather defer capital expenditure or do the job once and forget it.

For homeowners staying long-term in a property they love, we'll usually push slightly towards a full re-roof. For landlords, commercial properties or short-term owners, liquid systems are often the better economic answer.