STP SuperThermoLay SBS
A spun-bonded polyester-reinforced, SBS polymer-modified bituminous membrane built for structures that flex and for climates that swing from freezing to blistering.
What is it?
A pre-fabricated, torch-applied waterproofing membrane made of SBS (styrene-butadiene-styrene) modified bitumen coated onto a 160 gsm non-woven spun-bonded polyester core.
Where is it used?
Roofs, terraces, podiums and roof gardens above ground; basements, retaining walls and bridge decks below ground; and reservoirs and tanks.
Why use it?
Its SBS-rubber modification keeps the membrane elastic and workable even at sub-zero temperatures, so it accommodates structural movement without cracking and bridges hairline shrinkage on the slab.
How is it applied?
Prime the substrate with ShaliTex Primer, then heat-fuse the membrane to the deck with an LPG torch, lapping 75 mm along the length and 100 mm across the width.
About STP SuperThermoLay SBS
STP SuperThermoLay SBS sits in the elastomeric family of prefabricated bitumen membranes. The waterproofing chemistry is styrene-butadiene-styrene rubber blended into refined bitumen, and that blend is factory-coated onto a 160 gsm spun-bonded non-woven polyester mat. The polyester carrier is what gives the sheet its tensile backbone and lap-joint integrity, while the SBS rubber is what makes the compound behave less like brittle asphalt and more like a flexible, self-recovering rubber sheet. The result is a dimensionally stable, impervious layer that resists weathering and ageing and holds its shape across a wide temperature band.
For engineers and applicators in India, the SBS grade earns its place where the substrate moves or where site conditions run cold. SBS-modified membranes stay pliable and easy to unroll at low temperatures, which matters for hill-station projects, cold-store roofs, chilled-water tanks and any deck detailed with tight sloping corners or upstands. It is engineered as a single-layer protected system for most roofing and tanking work, and it also serves as a dependable base ply in multi-layer build-ups and damp-proofing courses. Space Arc Engineering supplies and applies it as an authorised STP channel across Delhi NCR and Pan-India.
The technical insight
The performance difference between an SBS membrane and a plain-bitumen or APP one comes down to how the polymer network behaves at the two ends of the thermometer. SBS is a thermoplastic elastomer: its styrene domains anchor a rubbery butadiene mid-block, so when it is blended into bitumen the compound gains genuine elastic recovery rather than just softening and hardening. In practice that means the sheet stays flexible down to about -15C (low-temperature flexibility per the TDS) and can be torched and rolled without the compound fracturing at corners. When the slab expands and contracts through the day-night cycle, the membrane stretches with it and springs back instead of tearing, which is why the elongation figures sit at roughly 45-50%. The polyester core carries the tensile load, so movement is shared between an elastic compound and a strong, dimensionally stable carrier, giving the long service life the material is specified for.
Where it is used
- Flat and low-slope roof and terrace waterproofing as a protected single-layer system
- Podium decks and roof gardens where the membrane must resist buried, permanently wet conditions
- Basement rafts and external retaining walls for below-grade tanking
- Bridge decks and other movement-prone civil structures
- Water-retaining structures such as reservoirs and tanks
- Cold-climate and hill-station roofs where sub-zero flexibility is required
- Base ply in multi-layer bituminous build-ups
- Damp-proofing courses and concealed concrete surfaces
Key advantages
- Stays flexible and easy to lay at sub-zero temperatures thanks to SBS rubber modification
- High elastic recovery accommodates structural and thermal movement without cracking
- 160 gsm spun-bonded polyester core delivers strong tensile strength and reliable lap joints
- Maintains shape at high temperatures (flow resistance to 100C) and withstands thermal shock
- Resistant to chlorides, sulphates and phosphates commonly found in ground water
- Impervious, weather- and ageing-resistant film for a long protected service life
- Handles difficult basement and foundation detailing where malleability at corners matters
- Available in plain finish or mineral/slate finish for exposed protection needs
Limitations & considerations
- Torch application needs a trained applicator and open LPG flame, so it is unsuitable where hot works are prohibited (use ShaliBond APP cold adhesive instead in those zones)
- As a bitumen membrane it needs UV protection or screed/tile cover; it is not intended as a permanently exposed, unprotected finish
- Being sheet-based, complex geometries, penetrations and upstands demand careful detailing and overlaps to stay watertight
- Rated low-temperature flexibility is to about -15C per the TDS, so it is not a specialty grade for extreme polar service
- Torch heat and open flame require fire precautions on occupied or sensitive structures
- Supplied only in 3 mm and 4 mm thicknesses in 1 m x 10 m rolls, so very thin or bespoke builds are not catered for
Selection & best practice
Start with a clean, sound, dry substrate free of laitance and sharp projections. Prime with ShaliTex Primer at 0.3 L/m2 and let it dry fully; in humid conditions leave the primed surface overnight. Begin laying at the lowest point of the fall and work uphill, aligning side laps before bonding. Torch with the flame in an L-pattern, directing roughly 75% of the heat onto the roll and 25% onto the substrate and lap, then consolidate with a roller or wet cloth to expel trapped air. Seal every overlap with a round-tipped hot trowel, keeping 75 mm laps longitudinally and 100 mm transversely. Finish with Super Silver Shield for UV protection on non-trafficable roofs, or protect trafficable areas with 50 mm PCC dosed with ShaliPlast LW+ (or loose-laid tiles) over a ShaliGeoText 120/150 gsm separation layer.
Specifications
| Membrane type | SBS polymer-modified bituminous membrane |
| Reinforcement core | 160 gsm spun-bonded non-woven polyester |
| Thickness | 3 mm and 4 mm |
| Roll size | 1 m x 10 m |
| Low-temperature flexibility | -15C |
| Elongation (ASTM D-5147) | 45 +/- 10% longitudinal, 50 +/- 10% transverse |
| Tensile strength (ASTM D-5147) | 800 +/- 150 N/5cm longitudinal, 500 +/- 150 N/5cm transverse |
| Tear resistance (ASTM D-5147) | 160 +/- 75 N |
| Flow resistance / hydrostatic | 100C flow resistance; hydrostatic pressure resistant >110 PSI |
Industry use cases
Cold-climate and hill-station roofing
Sub-zero flexibility lets crews torch and detail the membrane in low ambient temperatures where APP sheets would turn brittle at corners and upstands.
Basements and below-grade tanking
Malleability at sloping corners plus resistance to chlorides, sulphates and phosphates in ground water suits raft slabs and retaining walls.
Bridge decks and civil infrastructure
High elongation and elastic recovery let the membrane track deck movement and thermal cycling without splitting over the joint lines.
Podiums and roof gardens
A robust, impervious protected layer that stands up to permanently wet, buried service under planters, screeds and paving.
Water tanks and reservoirs
Dimensionally stable, weather- and ageing-resistant sheet for water-retaining structures needing a durable single-layer system.
Frequently asked questions
What is the difference between SuperThermoLay SBS and the APP version?
What thicknesses and roll sizes are available?
How low a temperature can it be applied and used at?
Does it need a primer, and can it be laid without a torch?
Is it suitable for basements and structures in aggressive ground water?
How do I protect it once laid?
How we position STP SuperThermoLay SBS
SuperThermoLay SBS is the cold-flex specialist in STP’s torch-applied membrane range; where high-temperature and UV stability on exposed hot roofs matter more than sub-zero flexibility, the plastomeric SuperThermoLay APP grade is the sibling to specify. Complete the STP system with ShaliTex Primer, ShaliBond APP where torching is not allowed, Super Silver Shield as a reflective UV top-coat, ShaliPlast LW+ for the protective screed and ShaliGeoText as the separation geotextile. For projects that call for a seamless, liquid-applied alternative to a sheet, we can cross-refer to Dr. Fixit or Fosroc polyurethane and acrylic coatings from our other brand lines.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.