Roof Waterproofing Coatings · an Amrize brand100% silicone roof coating in a DIY-friendly 3.8-litre tin — sheds, garages, porches, dormers and small flat roofs, with the same ponding-proof silicone chemistry as our commercial systems.
The jobs this product is specified for, day in day out.
Small roofs where a full commercial pail would be wasted.
Awkward small areas a contractor would price heavily.
Extensions and outbuildings needing a proper waterproof membrane.
What the data sheet actually gives you on site.
The same silicone chemistry as our commercial systems — standing water does not re-emulsify it.
Alternate colours between coats so you can see your coverage, then finish in the colour you want.
ASTM E108 / UL-790, and the White meets Energy Star and CRRC reflectance requirements.
No spray kit needed — a 19–25 mm nap roller and two coats is the whole method.
The facts that matter, straight from the product data.
| Type | Single-component, air-dry elastomeric silicone roof coating |
| System | Minimum 2 coats to a 0.56 mm / 22 mil total dry film (3–4 coats on textured surfaces) |
| Coverage | Approx. 9–10 m² per 3.8 L tin per coat at 0.28 mm / 11 mil DFT |
| Application | Solvent-resistant 19–25 mm nap roller, or notched squeegee and back-roll on smooth decks — do not thin |
| Recoat | First coat dry in 3–12 hours; recoat as soon as it can be walked on |
| Performance | Tensile 2 MPa, 150% elongation, 0.06 perm — withstands permanent ponding water (ASTM D412 / E96) |
| Fire / cool roof | Class A (ASTM E108 / UL-790); White meets Energy Star and CRRC reflectance requirements |
| Colours | White, Gray, Green, Light Tan, Rustic, Medium Blue, Black, Brown, Red |
Type your area and we’ll do the maths — derivation shown, nothing hidden.
Everything from the manufacturer’s literature — open the part you need.
GacoFlex S4200 Silicone Roof Coating is ideal for waterproofing and restoring:
The same Gaco S4200 Silicone Roof Coating is used as the top coat. For ease of installation, consider using different colours for the base coat and top-coat. On flat roofs containing asphalt or EPDM, we recommend using a white coating to assist with solar reflectance, prolonging the protection of the roof deck whilst reducing solar gain.
Refer to the product-specific Product Health & Safety Data Sheet for complete guidance on handling, PPE requirements, and storage.
GacoFlex S4200 Silicone Roof Coating is ideal for waterproofing and restoring:
These products are designed to work together — buying the full system is what qualifies the warranty.
Written by our technical team — free to download, no email required.
PDFGacoRoof Product Data SheetOfficial Gaco PDS — coats, colours, cure and limitationsTell us about the building and we’ll spec the job free — the right system, the right quantities, and trade rates if you’re buying for a contract.
Tell us about your building and we’ll recommend the right system — foam, waterproofing or both — surveyed, specified and quoted at no cost.