STP ShaliUrethane BTD
A water-based, UV-stable, fibre-reinforced polyurethane liquid membrane that brushes on cold to give exposed roofs a seamless, crack-bridging, cool-roof waterproofing layer.
What is it?
A single-component, water-based, fibre-reinforced elastomeric polyurethane liquid membrane from STP that cures in place to a seamless, breathable waterproofing skin.
Where is it used?
Exposed RCC roofs and terraces, podiums, corrugated roofs, gutters, and over ageing APP/SBS/tar-felt membranes needing refurbishment.
Why use it?
It combines high elongation and crack-bridging with a white cool-roof finish (SRI 109) that reflects heat, so it waterproofs and lowers surface temperature at once.
How is it applied?
Prime the damp, prepared surface, then apply two coats at 1.0 kg/m2 each by brush or roller for a 1 mm dry film, with an optional fibre tissue for extra strength.
About STP ShaliUrethane BTD
ShaliUrethane BTD is STP Limited’s water-based, cold-applied polyurethane liquid membrane built for the one job most Indian roofs demand: staying watertight through monsoon downpours and then baking under summer sun without cracking or peeling. Unlike heat-applied bituminous felts, it goes down as a single-component liquid that you brush or roller straight onto a prepared, slightly damp deck. As it cures it knits into one continuous, jointless film that follows every parapet upstand, drain mouth and corner, so there are no laps or seams for water to sneak through. The formulation is fibre-reinforced and anti-algae, and it conforms to ASTM C 836 and ASTM D 6083-97a, the recognised references for liquid-applied and protected roofing membranes.
What sets BTD apart for terrace and podium work is its white cool-roof grade. STP quotes a Solar Reflective Index of 109 for the white version, which means the treated slab reflects a large share of incident heat instead of soaking it up. For occupied floors directly below an exposed roof, that reflectance translates into measurably cooler ceilings and lower cooling loads through the day. The membrane is also genuinely elastomeric, with elongation in the region of 350 percent and crack-bridging up to 2.5 mm, so it accommodates the daily thermal movement and shrinkage cracking that opens up on any large concrete roof. As the authorised distributor and applicator across Delhi NCR and Pan-India, Space Arc supplies BTD in Horizontal and Vertical grades along with the STP primers, latexes and protection coatings that complete a warranted system.
The technical insight
The performance of ShaliUrethane BTD comes from pairing a flexible polyurethane backbone with a fibre-reinforced, water-based carrier. Because it is single-component and water-borne rather than solvent- or heat-based, the film builds by evaporation and coalescence, letting you apply it on a slightly damp surface and even use the diluted product itself as a primer. Once formed, the cured membrane behaves elastically: it stretches to roughly 350 percent elongation and returns, which is exactly what lets it bridge cracks up to 2.5 mm as the slab expands and contracts through day-night and seasonal cycles instead of splitting over them. The white grade’s Solar Reflective Index of 109 (measured to ASTM C 1549 / C 1371 / E 1890) is the second mechanism at work: high solar reflectance keeps film and substrate temperatures down, which both reduces heat gain into the building and slows the thermal fatigue that ages ordinary coatings. The seamless, breathable nature of the film is the third piece, allowing residual construction moisture to escape as vapour while blocking liquid water from entering, so the membrane resists blistering that plagues fully impermeable systems on green or damp decks.
Where it is used
- Waterproofing of exposed RCC roofs and terraces on residential, commercial and institutional buildings
- Podium slabs and landscaped-deck decks ahead of protection screed and finishes
- Corrugated and profiled sheet roofs needing a cold-applied, seamless overlay
- Refurbishment and overlay of ageing APP, SBS or tar-felt membranes without full stripping
- Gutter, valley and box-gutter waterproofing where seamless detailing matters
- Cool-roof upgrades on non-trafficable slope roofs to cut heat gain (white grade)
- Vertical parapet upstands and terminations using the Vertical grade
- Small terraces and chajjas where a torch-applied membrane is impractical
Key advantages
- Seamless, monolithic, jointless film with no laps or overlaps to fail at seams
- Cold, single-component application by brush or roller; no torch, gas or hot works on site
- Can be applied on a slightly damp surface, cutting drying-down waiting time after rain
- White grade delivers a genuine cool roof, SRI 109, reducing heat gain into floors below
- High elongation (~350%) with crack-bridging up to 2.5 mm for real thermal movement
- Fibre-reinforced and anti-algae, with an optional geo-textile ply for higher mechanical strength
- Breathable membrane lets trapped vapour escape, reducing blistering on new or damp decks
- Conforms to ASTM C 836 and ASTM D 6083-97a for liquid-applied roofing membranes
Limitations & considerations
- Water-based cure needs dry weather; it cannot be applied when rain is imminent or on ponded water
- Total curing of 36 hours is required before any follow-on work, and a ponding test only after 14 days
- On trafficable roofs it needs a protection layer or a topcoat such as ShaliProtek PU HA; it is not a wearing surface
- Coloured, black and terracotta grades do not carry the white grade’s SRI 109 cool-roof benefit
- Metal and problem substrates need a DTM-type primer confirmed with STP’s technical cell
- Correct film build depends on applying the full two coats at 1.0 kg/m2 each; under-application compromises the 1 mm DFT
Selection & best practice
Start with the deck, not the drum. Remove loose gravel, dust, oil and laitance, grind the surface smooth, cut and fill cracks with PMC mortar (ShaliCrete : cement : sand at 1:2:5), and form 75 mm x 75 mm PMC coving at all upstands with ShaliSBR Latex as bond coat. Establish a 1:100 fall to drains so water never stands. Damp the surface without leaving ponding, then prime with ShaliPrime WB at 200 gm/m2, or dilute BTD 1:1 with water and prime at 400 gm/m2. Apply the first coat at 1.0 kg/m2 while the primer is still tacky; if higher mechanical strength is needed, bed a 45 GSM non-woven geo-textile or fibre-glass tissue into it with 50 mm overlaps. Let it dry 10-12 hours, then apply the second coat at 1.0 kg/m2 for a final 1 mm (1000 micron) DFT in two coats; add a third coat at 1.0 kg/m2 in heavy-duty areas. Turn the membrane up 200 mm and terminate into a parapet groove filled with PMC mortar. Protect vertical work by sanding at 200 gm/m2 and plastering, and horizontal work with ShaliProtek PU HA or a ShaliGeoText 200 separation layer under screed. Allow 36 hours cure and confirm with a ponding test after 14 days.
Specifications
| Product type | Water-based, single-component, fibre-reinforced elastomeric PU liquid membrane |
| Colour | White / Terracotta / Green (Black to specific order) |
| Solid content | > 80 % |
| Elongation (14 days, ASTM D 2370) | 350 ± 50 % |
| Tensile strength (14 days, ASTM D 2370) | 1.80 ± 0.1 MPa |
| Crack bridging | Up to 2.5 mm (no cracking, ASTM C 836) |
| Solar Reflective Index (white) | 109 (ASTM C 1549 / C 1371 / E 1890) |
| Service temperature range | -20 to 100 °C |
| Coverage / DFT | 2 coats @ 1.0 kg/m2 each for 1.0 mm (1000 micron) DFT |
| Standards / Pack / Shelf life | ASTM C 836 & ASTM D 6083-97a; 25 kg pack; 12 months sealed |
Industry use cases
Residential & Housing
Exposed terraces and roofs on apartments and independent houses where a cold, low-odour, seamless membrane can be applied over occupied floors, with the white grade cutting top-floor heat.
Commercial & IT Parks
Large office and mall roof slabs and podium decks where crack-bridging over thermal movement and a reflective cool-roof finish reduce both leakage risk and air-conditioning load.
Industrial & Warehousing
Corrugated and profiled sheet roofs and RCC utility roofs needing a seamless cold overlay without hot works near stored goods or process areas.
Roof Refurbishment
Ageing APP, SBS or tar-felt roofs that have started leaking can be overlaid with BTD instead of full stripping, restoring a monolithic waterproof skin quickly.
Institutional & Healthcare
Schools, hospitals and government buildings where low-VOC, torch-free application and a durable elastomeric roof membrane suit occupied, sensitive environments.
Frequently asked questions
Is ShaliUrethane BTD a bituminous membrane for buried basement walls?
How much material do I need per square metre?
Can it really be applied on a damp roof?
Is the white cool-roof claim genuine?
Can people walk on the finished membrane?
How long before I can test or build over it?
How we position STP ShaliUrethane BTD
ShaliUrethane BTD sits in STP’s exposed-roof waterproofing line as the go-to fibre-reinforced PU membrane with a true cool-roof white grade. Space Arc supplies it as a complete system with the STP consumables the TDS calls for: ShaliPrime WB primer, ShaliSBR Latex for coving and bond coats, ShaliPlast IW integral waterproofer for screeds and plaster, ShaliProtek PU HA where the roof must take foot traffic, and ShaliGeoText 200 as a separation layer under protection screed. Where a client prefers a cementitious rather than a PU chemistry, our Fosroc range offers Brushbond RFX as a surface-applied, breathable, crack-accommodating alternative for the same roof-and-terrace duty. For below-grade and buried concrete, steer clients away from BTD toward a dedicated below-ground membrane instead. Space Arc’s engineers will match the grade, primer and protection to your substrate and exposure across Delhi NCR and Pan-India.
Fosroc Brushbond RFX — Choose Brushbond RFX when a specifier wants a two-component acrylic-cementitious, breathable, crack-accommodating coating for the same exposed roof, terrace or water-tank duty instead of a PU liquid membrane.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.