Collection: GacoFlex Silicone & Urethane Roof Coatings

What are GacoFlex liquid roof coatings?

GacoFlex is a range of liquid-applied coatings used to restore and waterproof existing roofs. The coatings form a seamless, fully adhered membrane over a suitably prepared surface. The range includes S42 silicone, U9 urethane and GacoRoof silicone systems for different roof types and applications.

Can GacoFlex restore a roof without removing the existing covering?

Yes, where the existing roof covering and underlying structure are suitable for refurbishment. Applying a coating can extend the life of the roof without a complete strip-off. However, wet insulation, unsound materials and structural defects must be assessed and addressed before application.

What is the difference between GacoFlex S42, U9 and GacoRoof?

GacoFlex S42 is a silicone system for roof restoration, including flat, profiled metal and suitable fibre-cement roofs. It resists UV exposure and permanent ponding water.

GacoFlex U9 is a urethane system for roofs and decks requiring a hard-wearing surface, including areas subject to traffic where specified.

GacoRoof is a brush- or roller-applied silicone coating for smaller roofs, such as garages, extensions, sheds and dormers.

Which coating is suitable for roofs with ponding water?

GacoFlex S42 and GacoRoof silicone coatings resist permanent ponding water once correctly applied and cured. The appropriate system will depend on the roof covering, condition and project requirements. Roof outlets and drainage should still be maintained.

Can GacoFlex be applied to felt or asphalt roofs?

Suitable felt, asphalt and other bituminous roofs can be refurbished using the specified coating system. For S42 applications, A4271 Bleed Trap Base Coat is used where required to help prevent bituminous oils migrating through and staining the silicone finish. Always confirm substrate compatibility before ordering.

Can GacoFlex S42 be used on profiled metal roofs?

Yes, S42 can be used to waterproof suitable profiled metal roofs. Preparation includes addressing corrosion and defective components, followed by detailing seams, laps and fixings with the specified products before applying the main coating. The condition of the existing sheets will determine whether refurbishment is appropriate.

Is GacoFlex suitable for fibre-cement or asbestos-cement roofs?

S42 can be specified for suitable fibre-cement roofs. Asbestos-cement roofs require specialist assessment and an appropriate method of work before any preparation or coating takes place. Coating does not remove the asbestos, and the sheets must not be disturbed during routine preparation.

Which system is suitable for walkways and roof terraces?

GacoFlex U9 is the system intended for roofs and decks requiring resistance to traffic. It combines U91 Base Coat with U92 UV-Stable Top Coat and H.E.R. Polyurethane Sealant for detailing. The full specification must suit the intended use, drainage and slip-resistance requirements.

Can GacoFlex U9 be used in areas with vehicle traffic?

U9 can be specified for certain areas subject to vehicle traffic. Suitability depends on the substrate, construction and expected use, so a project-specific specification should be obtained before purchasing or applying the system.

Do GacoFlex coatings need a primer?

Some substrates require a primer or specialist base coat, while others may be suitable for direct application following preparation and adhesion testing. The requirement depends on the coating selected and the existing roof surface. Always follow the relevant technical data sheet and project specification.

How should the roof be prepared before coating?

The roof must be clean, dry, sound and free from contamination or loose material that could affect adhesion. Repairs and detailing should be completed using compatible products before the main coating is applied. An adhesion test is recommended to confirm that the proposed system bonds adequately to the surface.

How are seams, joints and roof details waterproofed?

Use the detailing products specified for your chosen system. S42 uses SF42 Seam Sealant for seams and details, with GacoPatch for suitable localised repairs. U9 uses H.E.R. Polyurethane Sealant, while GacoRoof uses Liquid Roof Tape over seams, joints and fixings before coating.

Can GacoRoof be applied with a brush or roller?

Yes. GacoRoof is designed for brush or roller application in two coats, making it a practical option for smaller roofs without specialist application equipment. Correct preparation, coverage and detailing remain essential.

What sizes are available in the GacoRoof range?

GacoRoof silicone coating is available in 3.8 litre tins and 18.9 litre pails. Choose the quantity according to the measured roof area and the coverage rate specified for your substrate.

How much coating will I need?

Quantities depend on the roof area, surface texture, substrate and required application rate. Allow for upstands, penetrations and other details as well as the main roof area. Use the relevant technical data sheet to calculate the full system requirements, including primers, sealants and repair products.

Can the coatings be applied in any weather?

No. Application conditions must meet the requirements of the selected product. Check the technical data sheet for temperature, moisture and curing restrictions, and allow a suitable weather window for preparation, application and curing.