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RAINPROOF PRG 909
- Roof garden leakage
- Sloped roof leakage
- Waterproofing over old bitumen
- Leaking metal sheet roofs
RAINPROOF PRG 909 is a single-component, cold-applied polyurethane rubberized elastomeric grey waterproof exterior coating — self-curing, with exceptional elongation and crack-bridging across a wide temperature range. Designed by blending special polyurethane resins, rubber, and water-repellent silicon fillers with gelling agents, it forms an impervious, tough, abrasion-resistant membrane resistant to fungus, algae, salts, mild acids and alkalies. Suitable for terraces, sloped roofs, MS/ACC sheets and retaining walls. Can be applied over existing bitumen-coated surfaces.
Specifications
Figures are controlled laboratory results. Actual site performance varies with substrate, temperature, humidity, application method and workmanship — please confirm the current product datasheet before specification.
Where to use RAINPROOF PRG 909: grey polyurethane waterproof coating for roofs and terraces
RAINPROOF PRG 909 is a grey polyurethane waterproof coating that is single-component, cold-applied and self-curing. It blends polyurethane resins, rubber and water-repellent silicon fillers into a tough, abrasion-resistant membrane. This PU rubberized coating is applied by brush or airless spray in two coats, diluted with water, on exterior surfaces.
RCC Terraces & Sloped Roofs
Two coats form an impervious membrane with 700% elongation.
Domes & Folded Plate Roofs
Applied by brush or airless spray on domes and folded plates.
Stone, Brick & Wood Walls
Resists fungus, algae, salts, mild acids and alkalies on walls.
Corrugated AC Sheets & Metal Roofing
Covers 50–70 sq.ft/kg per coat on metal surfaces.
External Side of Retaining Walls
Tough, abrasion-resistant membrane on the outer face of the wall.
Over Existing Bitumen-Coated Surfaces
Adheres well even over residual bitumen stains after removal.
For sloped roof leakage or a terrace that needs a dark grey finish, coverage is 40–60 sq.ft/kg per coat on concrete. This elastomeric grey roof coating has 68% solids, 700% elongation at break, 2 mm crack bridging, adhesion above 2.0 N/mm² and 2000 Hrs UV resistance with no deterioration. Standards listed include ASTM D 2823 and C-836. Seal cracks with ROOFSEAL PS/PU sealant first. Apply the second coat after 6–8 hours and cure for 3 days before foot traffic.
Armstrong Chemicals supplies RAINPROOF PRG 909 to sites across Telangana, Andhra Pradesh, Karnataka, Kerala and Tamil Nadu, including Hyderabad, Vijayawada, Bengaluru, Kochi and Chennai.
The Grey Alternative — More Solids, Same Protection
68% solids, 700% elongation, 2mm crack bridging, 2000-hr UV resistance — a dark grey polyurethane rubberized elastomeric coating built for terraces, retaining walls and metal roofs where black isn't the right finish.
Get a QuoteWhen Black Isn't the Right Answer
Black rubberized coatings are effective but can be visually unsuitable for exposed terraces, architectural concrete or surfaces where a neutral, discreet finish is preferred.
The RAINPROOF PRG 909 Advantage
The same polyurethane rubberized elastomeric protection — 700% elongation, 2mm crack bridging, 2000-hr UV resistance — in a dark grey finish with 68% solids content and an explicit EN 1542 adhesion spec.
68% Solids — More Material per Litre
At 68% solids content, RAINPROOF PRG 909 deposits more actual membrane material per litre of product than a 58%-solids coating — contributing to a denser, more durable dry film.
Built-In Adhesion Spec
Adhesion to concrete is independently verified at >2.0 N/mm² to EN 1542 — a specification not listed in every rubberized elastomeric coating, and relevant for demanding substrates.
Choose Your Application System
2-Coat Standard System
Standard waterproofing for terraces, walls and metal roofs.
Built to Protect, Built to Last
Polyurethane rubberized protection in a dark grey finish, built for exposed structures.
700% Elongation, 2mm Crack Bridging
PU rubberized membrane stretches 700% and bridges cracks up to 2mm wide with no cracking — moving with the substrate through seasonal expansion and contraction.
68% Solids Content
Higher solids than standard elastomeric coatings — more membrane material deposited per litre, for a denser dry film at the same coverage rate.
2000-Hr UV Resistance
No deterioration after 2000 hours of UV exposure (ASTM G-154:2000) — and resistant to mild acids, alkalies, oils, solvents and other chemicals.
Multi-Substrate Bond
Bonds to cement concrete, mortar, asbestos, mild steel and existing bitumen-coated surfaces — one product across roofing, walls and metal structures.
How to Use
Clean surface thoroughly — remove dirt, dust, rust, loose paint, damaged plaster, oils, fungus and algae with wire brush and water wash. Acid-etch first if required, before the water wash.
Seal all cracks with ROOFSEAL PS/PU sealant before coating.
Apply 1st coat of RAINPROOF PRG 909 diluted with up to 20% water, by brush or airless spray.
After 6–8 hours, apply 2nd/final coat diluted 10–20% with water over the first coat.
Allow to cure for 3 days before foot traffic or water-flood testing for leakage.
If the area was previously bitumen-coated, remove as much existing bitumen as possible before applying — product still adheres well even over residual bitumen stains. If a primer coat is required, dilute 50% with water and apply first.
Optional: embed fibre mesh / fibreglass tissue in the first wet coat for extended warranty; apply the second coat over it.
Applicable Areas
Packing & Storage
Available in 1, 5, 10 & 20 Litre packs. Shelf life of 12 months from manufacture, stored between 10°C and 30°C in original packing.
Precautions
Sprinkle water during the first coat if applying around 40°C. Avoid application below 10°C — it prolongs drying and curing. Store in a cool, dry place. Ensure surface is perfectly clean before application.
Cleaning of Tools
Tools and equipment clean up with water immediately after application.
Coverage Calculator
Enter your surface area to estimate how much RAINPROOF PRG 909 you need. Coverage rate: 40 sq.ft per litre per coat.
Product Brochure
Download Technical Datasheet
Full specifications, application systems, layering guides, and coverage tables.
Frequently Asked Questions
Ready to protect your structure?
Request a quote and your nearest Armstrong distributor will contact you directly.
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