Home›Commercial Roof Waterproofing
Seamless, cold-applied GacoFlex silicone, acrylic and urethane systems for commercial and industrial roofs across the UK — waterproofing, cut edge corrosion, asbestos encapsulation, gutter lining and cool-roof coatings, all over your existing roof with no tear-off.
Building owners, tenants and facilities managers: get free expert advice and a fixed-price quote. We survey and specify, then match you with an approved contractor from our UK-wide network — backed by a 20-year manufacturer-backed product warranty.
Liquid roof waterproofing is a cold-applied coating rolled, brushed or sprayed straight onto your existing roof. It cures into a seamless, fully-bonded elastomeric membrane with no joints, laps or mechanical fixings — sealing exactly the points where commercial roofs leak. GacoFlex systems bond to metal, felt, single-ply, concrete and asbestos-cement substrates, so there is no tear-off, no re-sheeting and no need to close the building.
A correctly specified coating system seals vulnerable roof details after suitable preparation and repairs.
Restore the roof you have instead of stripping and re-sheeting it — a fraction of the capital cost and disruption.
Cold-applied over the live building. No tear-off, no vacating, no downtime for your operation or tenants.
A 20-year manufacturer-backed product warranty from GacoFlex (an Amrize brand), installed by an approved contractor from our UK network.
White reflective coatings can reduce solar heat absorption. Any effect on an EPC rating requires a building-specific assessment.
Applied without a torch or open flame. Site-specific fire precautions and safe-working measures still apply.
The same GacoFlex range covers the details that make a commercial roof watertight — edges, gutters, asbestos and reflectivity.
Stop active corrosion at metal sheet edges with the GacoFlex multi-stage primer, SF42 seam seal and silicone topcoat system.
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Gaco silicone coatings lock in surface fibres and shield asbestos-cement roofs from UV and moisture — no intrusive removal.
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Joints and fixings reinforced with SF42 SeamSeal, then a seamless Gaco coating — watertight, flexible, ponding-resistant.
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Gaco silicone and urethane systems for flat and low-slope commercial roofs, with a 20-year manufacturer warranty.
Learn more →GacoFlex systems are specified across the UK’s commercial and industrial estate — on every roof form from profiled metal to concrete decks.
Large-area profiled metal, cut edge and ponding.
Book a survey →Plant, production and process-unit roofs.
Book a survey →Fume, vibration and heavy-use metal roofs.
Book a survey →Ponding-resistant seamless silicone membrane.
View page →Steel, aluminium and coated profile sheeting.
Book a survey →Encapsulate without intrusive removal.
View page →Reflective roof finishes to help manage summer heat gain.
Book a survey →Out-of-hours, rapid-cure over trading units.
Book a survey →Whether you need a highly reflective energy-saving coating or a robust waterproof membrane for long-term protection, we specify the GacoFlex system that best matches your building’s roof, drainage and budget.
A premium 100% silicone membrane for roofs needing the highest levels of waterproofing, flexibility and long-term protection — built around Gaco S42, with SF42 fibre-reinforced seam seal at laps and details.
A cost-effective, weather-resistant elastomeric acrylic (127 Series) ideal for large commercial roofs where reflectivity, surface protection and value are the priorities.
A heavy-duty two-coat urethane system (U91 base + U92 aliphatic top coat) for roofs that demand exceptional impact, abrasion and chemical resistance — pedestrian decks, plant rooms and podiums.
Gaco S42 is the flagship — but a fully warrantied installation also relies on two specialist companion products. Together they form the silicone roof system specified across UK warehouses, factories and commercial buildings.
Specialist cleaning solution that removes dirt, algae, moss and surface contaminants — ensuring maximum adhesion of the silicone coating system.
Fibre-reinforced silicone seam sealant for laps, fixings, fasteners and detail areas. High-build formula bridges joints and movement points permanently — no separate scrim needed.
Instant-cure silicone sealant for targeted leak repairs and emergency waterproofing — can be applied in wet or dry conditions, even during active rainfall.
Duratite specifies all three GacoFlex systems — each has a place. The right coating depends on your roof’s condition, drainage, traffic level and long-term goals. We confirm the best fit on a free site survey.
| Compare the system | RECOMMENDEDSilicone — Gaco S42Flagship · flat & low-slope | Acrylic — GacoFlex 127Cost-efficient · cool roof | Urethane — U91/U92Heavy-duty · trafficked |
|---|---|---|---|
| Best suited to | Flat & metal roofs with ponding water | Large reflective metal roofs & cool-roof projects | Pedestrian decks, plant rooms & trafficked areas |
| Ponding water resistance | Excellent | Poor | Very good |
| UV / weather resistance | Outstanding | Very good | Outstanding U92 aliphatic top coat |
| Foot-traffic durability | Limited | Limited | Walk-on rated |
| Cool-roof / energy savings | High (white) | High (white) | Standard |
| Recoatable at end of life | Yes silicone-on-silicone | Yes compatible substrate | Yes recoat with U92 |
| Application | Single coat, cold-applied | 2-coat, cold-applied, fast drying | 2-coat (base + top), cold-applied |
| Manufacturer warranty | Up to 20 yrs | Up to 15 yrs | Up to 20 yrs |
| Typical cost (indicative) | ££ from £20/m² fully installed | ££ from £20/m² fully installed | £££ from £30/m² fully installed |
UK specifiers, contractors and building owners regularly compare these systems for commercial flat-roof and metal-roof projects. The table below sets them out side-by-side using publicly available manufacturer data — no spin. Use it as a starting point, then talk to a specialist for a recommendation that suits your roof.
| Compare the systems | RECOMMENDEDGacoFlex S42Duratite — UK distributor | PolyroofUK manufacturer | Triflex ProDetailPMMA · Germany |
|---|---|---|---|
| System type | 100% silicone, single-coat | Polyester-reinforced PU | PMMA (acrylic resin) |
| Manufacturer warranty | Up to 20 years | Up to 20 years Protec / IBG variants | Up to 25 years specifier scheme |
| Application | Cold-applied, brush/roller/spray | Cold-applied, fully reinforced | Cold-applied, fast-cure PMMA |
| Cure time (typical) | 4–8 hrs rainproof; 24 hrs full | 24–48 hrs resin + reinforcement | ~30 mins rainproof PMMA |
| Solar reflectance (CRRC) | SR 0.91 white S42 | Not CRRC rated | |
| Ponding water rating | Permanent ponding rated | Drainage required | |
| Typical UK cost (fully installed) | £20 – £30 / m² | Ask the manufacturer | Ask the manufacturer |
| Pedestrian rated | Add U92 top coat for traffic | Yes with anti-slip topcoat | Yes heavy-duty PMMA |
| Best for | Flat & metal roofs with ponding; refurbishment over existing | Flat roof refurbishment with reinforcement layer | Complex details, balconies, fast-cure deadlines |
Commercial roof waterproofing with GacoFlex silicone typically costs £20–£30 per m² fully installed (heavy-duty urethane around £30–£40 per m²). A 1,000 m² flat or metal roof costs roughly £20,000–£30,000, a fixed written price. All quotes are fixed-price after a free site survey from Duratite’s technical team.
| Roof size | RECOMMENDEDGacoFlex coating costFully installed | Full replacement | Saving |
|---|---|---|---|
| 500 m² | £10,000 – £15,000 | £50,000 – £75,000 | 60–80% |
| 1,000 m² | £20,000 – £30,000 | £100,000 – £150,000 | 60–80% |
| 2,500 m² | £50,000 – £75,000 | £250,000 – £375,000 | 65–80% |
| 5,000 m²+ | POA — £18–£28/m² fully installed | £450,000+ | 70–80% |
Our coatings are engineered for a wide variety of existing commercial roof constructions. Gaco coatings adhere directly to most surfaces — including weathered or porous substrates — with minimal surface preparation required in many cases.
Six sectors account for over 80% of UK liquid-roof refurbishments. We specify the system, reinforcement and programme to each.
Large-area profiled metal, cut edge, lap-seam leaks and ponding around rooflights. S42 single-coat, ~£20–£30/m² fully installed. 2,000–20,000 m²+.
For suitable felt and single-ply roofs, consider 127 acrylic or S42 with work planned around school holidays. White finishes can help reduce summer heat gain.
Zero clinical disruption; low-odour, cold-applied. Plant decks above theatres via U91/U92 walk-on urethane, no shutdown.
White S42 has a CRRC initial solar reflectance of 0.91 and can help reduce summer heat gain. Assess energy performance for the individual building.
Leak-sensitive (stock liability), trading-hours-sensitive. Out-of-hours rapid-cure silicone, rainproof in 4–8 hrs.
Cut-edge corrosion, ponding, fume exposure and vibration. S42 + SF42 fibre-reinforced, cold-applied, no hot work.
GacoFlex white reflective coatings can reduce solar heat absorption and may reduce cooling demand. Results depend on the building, climate and roof specification. Manufacturer warranty terms depend on the chosen system.
A roof coating alone does not establish MEES compliance or guarantee an EPC rating. Seek building-specific advice from a qualified energy assessor.
Each case shows the building type, the problem, the system applied and the outcome.
Original profiled metal roof coated in place with the GacoFlex S42 Series silicone system — no tear-off and no stripping of the existing sheets. Coating completed July 2025. Building owner Treveth Holdings LLP; installed by Gwella Contracting Solutions Ltd.
We’re your single point of contact: Duratite surveys and specifies the system, then matches you with a vetted contractor from our UK-wide approved network to carry out the work.
Owners, tenants and facilities managers send the building, roof and a few photos.
Substrate, ponding, cut edges, access and drainage assessed on site.
System, reinforcement and any traffic top coat, at a fixed, fully installed price.
A vetted contractor from our UK network cold-applies the system — no tear-off, building stays open.
20-year manufacturer-backed product warranty and documentation.
Send the building type, roof and a few photos and we’ll book your free site survey. For active leaks, GacoPatch gives an instant-cure repair — even in the wet — while we plan the full system.
Straight answers on cost, lifespan, systems, asbestos, cut edge, cold-weather application, EPC and warranties. Can’t see yours? Ask us directly and we’ll come back to you the same working day.
Active leak? Stop it fast, without a strip-out or full roof replacement.
Learn more →OverlayExtend the life of a tired flat roof at a fraction of replacement cost.
Learn more →SystemsThe GacoFlex coating systems themselves — S42, SF42 and the U9 series.
Learn more →Flat roofsSilicone and urethane systems for flat and low-slope roofs.
Learn more →Tell us about your roof — type, approximate size and the problem. We survey it free, design the right GacoFlex system and issue a fixed quote with a 20-year manufacturer-backed warranty.
Prefer to talk? Call 01208 832 602 — Mon–Fri, 8am–5pm.
Mon–Fri 8am–5pm · 01208 832 602
Tell us about your building and we’ll recommend the right system — foam, waterproofing or both — surveyed, specified and quoted at no cost.
