Liquid-applied roof coatings that waterproof, seal and protect asbestos cement roofs — no removal, no fibre disturbance, no disruption. Need the underside sealed as well? See our asbestos encapsulation service (spray foam underside + coating).
Asbestos cement roofs, when in good condition, pose minimal immediate danger. However, over time, exposure to UV radiation, freeze-thaw cycles, moss growth and moisture ingress leads to surface degradation — causing fibres to become friable and increasingly hazardous.
Asbestos cement becomes porous over time as the cement matrix breaks down. This leads to water ingress, leaks, damp and structural damage.
Weathered asbestos surfaces release harmful fibres into the environment. This creates HSA compliance issues and health risks for occupants.
Uninsulated single-skin sheets have virtually no thermal resistance. This makes asbestos roofs a major source of heat loss in buildings.
Many commercial and industrial buildings across Ireland and Northern Ireland are still fitted with asbestos cement roofing sheets installed prior to the 1990s. As they age, these roofs leak, degrade and become a liability.
Duratite Building Products supplies three Gaco liquid-applied coating systems — S42 Silicone, 127 Acrylic and U92 Urethane — that waterproof asbestos roofs directly, without removal or fibre disturbance. This advanced method allows property owners to manage asbestos risks without the disruption, expense, or regulatory challenges of full asbestos removal.
Our specialist coating systems are designed to:
Seal and encapsulate asbestos surfaces to prevent fibre release.
Lock in loose particles and bind the roof surface.
Prevent further degradation from weather, UV and pollutants.
Extend the roof’s lifespan by 10–20 years or more.
Avoid full removal, disruption to operations, or costly over-sheeting.
Simplify future removal by stabilising the surface and reducing contamination risk.
See the transformation. Weathered, leaking asbestos roofs restored to watertight, protected surfaces with Gaco coating systems.
Before
AfterA straightforward four-step process to waterproof your asbestos roof with a liquid-applied coating system.
Full site survey to assess condition, identify damage and recommend the right system.
GacoWash removes moss, algae, dirt and residues without disturbing asbestos fibres.
Damaged areas repaired, joints sealed and primer applied for optimal adhesion.
Two coats of your chosen system — S42 Silicone, 127 Acrylic or U92 Urethane.
Not all asbestos roofs need to be removed. In many cases, encapsulation is a faster, safer, and more cost-effective solution — especially when the cement sheets are weathered but not crumbling. If you’re facing roof leaks, ageing materials, or insurance concerns, encapsulating your roof with spray foam and silicone coatings can extend its life and mitigate risk without disrupting your business.
The asbestos cement sheets are weathered but intact.
You have persistent leaks or moss growth but no structural failure.
You want to avoid downtime for your building or business.
You need to reduce long-term liability without capital expenditure on re-roofing.
You’re looking to improve insulation without altering the roof structure.
The same roof, two very different routes. Here’s how coating-based encapsulation compares with stripping the roof off.
| What it means for you | Gaco Encapsulation | Full Removal |
|---|---|---|
| Typical cost | Coated in place, no removal | High cost, plus disposal |
| Fibre disturbance | 0% — fibres sealed in place | High safety risks |
| Asbestos waste disposal | None — avoided entirely | Disposal costs apply |
| Business disruption | None — occupants stay in place | Disruption and downtime |
| Scaffolding | Not required | |
| Roof life | Extended by 10–20+ years | Re-roofing capital expenditure |
| Warranty | 20-year manufacturer-backed product warranty option |
One of the key benefits of asbestos roof encapsulation with a silicone coating is that it makes any eventual removal significantly safer. The hardened, sealed surface minimises airborne fibre release during dismantling and can reduce the overall risk profile of the structure.
In many cases, coating the asbestos roof buys valuable time, allowing building owners to plan for eventual removal in line with refurbishment schedules or regulatory timelines — without rushing into costly, disruptive action.
Three proven liquid-applied systems that waterproof asbestos cement roofs in situ — no removal, no disruption, no fibre release.
Cures quickly in real-world site conditions.
Accommodates movement without cracking or splitting.
Prevents further chalking and surface disintegration.
Minimal upkeep — can be recoated to extend life.
Silicone System100% silicone, single-component, moisture-cure coating. The premium choice for long-term asbestos roof protection.
Acrylic SystemWater-based acrylic elastomeric coating for reliable, cost-effective waterproofing over asbestos cement surfaces.
Urethane SystemTwo-component aromatic urethane for demanding applications where foot traffic or mechanical wear is expected.
The full GacoFlex asbestos roof waterproofing system, supplied direct by Duratite Building Products.
GacoWash™ is a powerful, non-hazardous concentrated cleaner formulated to remove dirt, biological growth, and contaminants from roofing substrates prior to coating. Specifically developed to prepare surfaces for GacoFlex™ silicone roofing and waterproofing systems, it ensures optimal adhesion and long-term performance of the coating system.
GacoFlex™ SF4200 SeamSeal™ is a premium, high-adhesion silicone-based moisture-curing sealant for seams, laps, joints, and fasteners on commercial and industrial roof systems. As part of the GacoFlex S42 silicone roof coating system, it delivers excellent flexibility, durability, and long-term weather resistance in demanding applications.
GacoFlex™ S4200 is a premium, liquid-applied silicone roof coating engineered to deliver long-term waterproofing protection across a wide range of substrates. This high-performance elastomeric system forms a seamless, monolithic membrane that resists ponding water, UV degradation, and thermal movement — extending roof service life without the need for costly tear-offs.
Why not check out GacoPatch, the instant, one-coat solution for emergency roof repairs.
Old or ageing roofs — flat or pitched — are prone to leaks that can cause serious damage if left untreated. In homes, this often means damp, mould, rotting timbers and costly repairs. In commercial buildings, leaks can disrupt operations, damage stock or equipment, and create safety risks.
Applying Gaco asbestos roof encapsulation early helps avoid these problems. Our spray foam and silicone solutions form a seamless, fully bonded barrier that seals vulnerable roof areas, prevents water ingress, and extends the life of your roof — without tear-off or disruption.
Whether you’re protecting a home, warehouse, school, or office, early treatment gives long-term assurance that your roof stays watertight and your building stays protected.
Duratite projects in the UK and Northern Ireland, completed by Duratite-approved installers using Gaco coating systems.
Our island-of-Ireland reference is SAICA Warrenpoint, Co. Down: 1,090 m² of asbestos cement roof encapsulated with closed-cell foam and GacoFlex U91/U92. Below are two projects in England using the same Gaco systems: a coating-only job in Bristol and a full foam-and-silicone encapsulation in Surbiton. Open either one for the complete story.
Bristol, England Coating-Only System · Commercial BuildingA leaking, weathered asbestos cement roof sealed with a seamless GacoFlex S42 silicone membrane — leaks stopped, no removal, not a single fibre disturbed.
Leaks stopped completely Zero fibre disturbance 20-year manufacturer-backed product warranty Read the full case studyHide the full case studyA commercial building in Bristol had an ageing asbestos cement roof that was leaking, weathered and increasingly vulnerable to water ingress. The client needed a waterproofing solution that would seal the roof without the cost and disruption of asbestos removal.
Duratite supplied and specified a GacoFlex S42 Silicone roof coating system — applied directly over the cleaned asbestos sheets:
The client now has a fully waterproofed asbestos roof with a seamless silicone membrane. The S42 coating sealed all surface degradation, stopped the leaks, and will protect the roof for 20+ years — all without disturbing a single asbestos fibre.
Surbiton, Surrey, England Foam + Silicone Encapsulation · Commercial BuildingA 1,575m² brittle asbestos roof cleaned, encapsulated with 25mm closed-cell spray foam and finished with two coats of GacoFlex S42 — completed in June 2025 without disturbing building occupants.
1,575m² roof area 25mm foam + 2 coats S42 20-year manufacturer-backed warranty Read the full case studyHide the full case studyA commercial building in Surbiton, Surrey, was suffering from an ageing and brittle asbestos roof spanning 1,575m². The existing sheeting had reached the end of its useful life — becoming increasingly vulnerable to water ingress, surface delamination, and environmental degradation. Aside from weatherproofing concerns, there were growing health and safety liabilities associated with the exposed asbestos cement, particularly due to visible algae, lichen, and moss growth holding moisture against the surface and weakening the substrate further.
The client wanted a solution that would:
Duratite proposed a single, integrated spray-applied system to clean, stabilise, insulate, and waterproof the roof in one seamless process — using our proven Gaco roofing technology. Our solution consisted of:
This all-in-one method was selected for its speed, safety, and long-term durability — avoiding the risks of asbestos disturbance or costly roof replacement.
A detailed site survey was carried out, and RAMS were submitted covering access strategy, fall protection, vapour management, and surface preparation.
The entire roof was treated with GacoWash, a high-performance roof cleaning agent designed to break down moss, algae, dirt, and environmental residues without damaging the fragile asbestos substrate.
Once fully dry, the roof received a continuous layer of 25mm closed-cell roofing spray foam — bonding directly to the cementitious asbestos panels, sealing cracks and gaps, and adding thermal resistance and structural rigidity.
The foam was overcoated with GacoFlex S42 in two coats — achieving UV stability, long-term water resistance even under ponding conditions, and a seamless, monolithic barrier that eliminates joint failures.
Proper preparation was critical to ensure optimal adhesion and longevity. The GacoWash system removed biological growth, atmospheric pollutants, and friable debris — without high-pressure washing that could disturb asbestos fibres.
After foam application, the surface was inspected for foam integrity and consistency, treated with a compatible primer where necessary, and coated with S42 silicone at the manufacturer’s specified film thickness, using calibrated wet film gauges. Drying times were carefully monitored between coats, with environmental conditions logged and verified.
The client now benefits from a fully encapsulated and insulated asbestos roof with a seamless waterproofing membrane and a 20-year manufacturer-backed GacoFlex product warranty. The entire 1,575m² system was completed in June 2025 within tight programme constraints and without disturbing building occupants.
Duratite’s one-pass, spray-applied system proves once again to be the gold standard for asbestos roof refurbishment, offering rapid installation, unmatched system integration, and lasting protection.
If your asbestos roof needs more than waterproofing — thermal insulation, structural reinforcement and full encapsulation — our spray foam encapsulation service combines closed-cell spray foam with a Gaco silicone topcoat in one seamless system.
Waterproof & seal the surface with S42, 127 or U92
Spray foam + silicone topcoat for insulation & encapsulation — view the service
Find out how we match you with a Duratite-approved Gaco installer.
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Find Out MoreFind out how to become a Duratite-approved installer.
Find Out MoreExpert guides, Ireland and Northern Ireland coverage and specialist experience across every commercial building type. Everything you need to make the right call on your asbestos cement roof.
With years of experience applying specialist coatings on fragile and hazardous roofs, our trained professionals follow strict safety protocols to ensure your project is handled with care and compliance. Every project is assessed individually, with bespoke specifications tailored to your building’s needs.
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Tell us about your building and we’ll recommend the right system — foam, waterproofing or both — surveyed, specified and quoted at no cost.
