Urethane roof & deck systems · an Amrize brandThe two-coat polyurethane system for surfaces that take traffic — balconies, walkways and plant decks, aged metal and asbestos cement roofs, and as the hard protective skin over spray foam. U91 does the waterproofing; U9200 takes the sunlight and the boots.
U91 base · U9200 topSpecified where a coating has to be walked on, driven on, or has to protect something else.
Traffic-bearing waterproofing on concrete and plywood. U91 exceeds ASTM C957 for pedestrian and vehicular decking — duty silicone is not designed for.
Renews weathered profiled steel and galvanised sheet, with Class A external fire spread on metal and a white finish that drops surface temperature.
Overcoats failing cement sheets without disturbance, and gives exposed closed-cell spray foam a hard skin against bird pecking and UV.
What the data sheet actually gives you on site.
Exceeds ASTM C957 for pedestrian and vehicular decking, with abrasion tested at 35 mg/min (ASTM C501).
With 350% elongation and 360 pli tear strength, the membrane moves with the deck instead of tearing at the details.
U9200 is aliphatic — 627% elongation, still 578% after 1,000 hours of accelerated UV, and CRRC-rated at SRI 107.
0.02 perm-inch through the U91 base, which matters over occupied space and insulated build-ups. Flexes to −26 °C.
Waterproofing comes from the base coat; longevity comes from the top coat. Different chemistries by design.
Single-component aromatic moisture-cure polyurethane at 80% solids — the waterproofing membrane. Applied at 0.41 L/m² for a 0.30 mm / 12 mil dry film per coat.
Aliphatic urethane wearing coat — UV-colour-stable, highly reflective white, and the surface that actually takes the traffic. One coat for the 10-year build, two for the 20-year.
Three approved detail methods: U91 with 66S polyester mesh, GacoMastic UF9022, or GacoFlex H.E.R. sealant — the fast option, overcoatable in 12–24 hours.
Total dry film decides the tier. At the heavier build a 20-year manufacturer warranty covering labour and material is available on registered, inspected installations.
The full U9 schedule — prep, details, base and top coats — with the arithmetic shown.
| Product | Quantity | Derivation |
|---|---|---|
| Enter a deck area to build the schedule. | ||
The facts that matter, straight from the product data.
| System | U91 aromatic moisture-cure PU base + U9200 aliphatic PU top coat |
| Warranty builds | 0.61 mm / 24 mil (10-year) · 0.91 mm / 36 mil (20-year) |
| Coat rate | 0.41 L/m² per coat — 0.41 mm wet, 0.30 mm dry film each |
| Tensile / elongation | U91 17.9 MPa at 350% · U9200 6.27 MPa at 627% (ASTM D412 / D2370) |
| Hardness / tear | Shore A 90 ±5 · U91 tear 360 pli (ASTM D2240 / D624) |
| Vapour | U91 0.02 perm-inch (ASTM E96) |
| Abrasion | 35 mg/min (ASTM C501) — heavy-traffic capable |
| Fire / cool roof | Class A external spread on metal (ASTM E108) · U9200 White SRI 107 |
| Low-temperature flex | Pass at −26 °C (ASTM D522) |
| Primers | E5320 epoxy on metal & asphalt · E5691 on concrete · GacoPrime LVOC on single-ply |
| Not suitable for | Over silicone coatings, and cold-store or cryogenic buildings |
Five stages. Coating failures are preparation failures.
Re-set failed fasteners, re-secure laps and seams, complete repairs in like-for-like materials.
Pressure wash and detergent clean; treat moss and algae with Sollac Hipolava at 20:1, 10–15 minute dwell.
Matched to the substrate — epoxy on metal and concrete, LVOC on single-ply, rust treatment on oxidised steel.
Seams, laps and penetrations in mesh-reinforced U91, GacoMastic or H.E.R. sealant.
U91 base, then one or two U9200 top coats to the film build your warranty tier requires.
Written by our technical team — free, no email required.
PDFU91 + U92 Urethane Application GuideTrafficked decks, metal & asbestos cement roofs, over spray foam — 7-page guide TDSGacoFlex U91 Product Data SheetOfficial Gaco PDS — properties, priming and application TDSGacoFlex U92 Product Data SheetSolar reflectance, adhesion and application data SPECU91 + U92 over Metal — 20-year specificationFull Gaco application specification at the 36 mil buildFree take-off from your dimensions, the right warranty tier, and trade rates for contract quantities. Surveyed and specified before you order.
Tell us about your building and we’ll recommend the right system — foam, waterproofing or both — surveyed, specified and quoted at no cost.
