STP ShaliTPO HG
STP’s single-ply, non-reinforced homogeneous TPO membrane for large flat roofs — hot-air welded seams, high solar reflectance and cold flexibility to -40C.
What is it?
A single-ply, non-reinforced homogeneous thermoplastic polyolefin (TPO) roofing membrane from STP Limited, factory-produced in rolls and joined on site by hot-air welding.
Where is it used?
Large commercial and industrial flat roofs, cold-storage and warehouse decks, green (root-resistant) roofs and rooftop solar installations.
Why use it?
It combines a reflective white surface that cuts roof heat gain with heat-welded seams that fuse into a continuous, watertight sheet, and it stays flexible in extreme cold.
How is it applied?
Rolled out mechanically fixed, fully adhered or ballasted, with overlaps fused by a hot-air welder to form homogeneous seams.
About STP ShaliTPO HG
ShaliTPO HG is STP Limited’s single-ply thermoplastic polyolefin (TPO) roofing membrane, supplied as a non-reinforced homogeneous sheet in rolls and welded into a continuous waterproof skin on site. Because the sheet has no internal scrim, the membrane is uniform through its full thickness — a construction that gives it clean weldability and lets it flex without a reinforcement layer dictating its behaviour. For engineers and roofing contractors working on large-format decks across Delhi NCR and pan-India, it is a modern alternative to torch-applied bituminous felts, replacing open-flame work and lap adhesives with clean, thermally fused joints.
The defining feature of any TPO system is the seam. Instead of relying on tapes or cold adhesives that can age and peel, ShaliTPO HG overlaps are joined with a hot-air welder that softens and fuses the two sheets into a single mass. A correctly formed weld is effectively as strong as the membrane itself, which is why TPO roofs are trusted on wide, exposed spans where a failed lap would be difficult to trace and expensive to repair. Space Arc Engineering supplies the membrane along with the accessories and trained application support needed to lay it correctly.
The technical insight
TPO is an ethylene-based polyolefin alloy engineered to marry two properties that rarely sit together: the weldability of a thermoplastic and the flexibility of a rubber. The homogeneous grade carries no polyester or glass scrim, so the whole cross-section is one material — that is what allows two overlapping sheets to be reheated and fused into a genuinely monolithic seam rather than a glued lap. The bright white, high-albedo surface reflects a large share of incident solar radiation (SRI in excess of 100), so the deck runs cooler, cooling loads drop and the polymer ages more slowly than a dark roof would. Stabiliser and UV-package chemistry gives the sheet its ozone and weathering resistance, while the polyolefin backbone keeps it pliable down to about -40C, meaning it will not turn brittle and crack in cold-store or high-altitude service. The trade-off of the non-reinforced construction is dimensional: without a scrim the sheet has less in-plane tensile restraint, so puncture resistance and the fixing/ballast strategy matter more in the design.
Where it is used
- Waterproofing large commercial and industrial flat roofs where heat-welded seams reduce lap-failure risk over long spans
- Cool-roof retrofits and renovations aiming to lower rooftop surface temperature and building cooling load
- Cold-storage and refrigerated warehouse decks that demand membrane flexibility at very low temperatures
- Root-resistant waterproofing layers under green-roof and podium landscaping build-ups
- Ballasted rooftop solar (PV) installations where the membrane sits beneath a loose-laid solar array
- Recyclable single-ply roofing on LEED and green-building projects seeking reflective, low-carbon materials
- Replacement of ageing torch-applied bituminous felt roofs with a flame-free welded system
- Detailing around parapets, penetrations and drains using welded membrane flashings
Key advantages
- Hot-air welded seams fuse into a continuous, homogeneous joint with no reliance on ageing tapes or adhesives
- High solar reflectance (SRI >100 in white) keeps the deck cool and helps cut building cooling loads
- Remains flexible down to about -40C, so it resists cold-induced cracking in cold-store and high-altitude service
- Flame-free installation removes the open-torch fire risk associated with bituminous felt roofing
- Strong UV and ozone resistance supports long service life on fully exposed roofs
- 100% thermoplastic and recyclable at end of life, aiding green-building and LEED documentation
- Root-resistant, making it suitable directly under green-roof and planted build-ups
- Lightweight single-ply sheet reduces dead load compared with multi-layer bituminous systems
Limitations & considerations
- Non-reinforced homogeneous construction has less in-plane tensile and puncture restraint than scrim-reinforced (PR/GR) TPO grades
- Seam quality depends entirely on correct welder temperature, speed and probe-tested laps — poor welding is the main failure mode
- Requires trained applicators and calibrated hot-air welding equipment, not a general labour trade
- Substrate must be clean, dry, sound and free of sharp projections before laying, or punctures and blisters can develop
- As a single-ply exposed system it needs a considered fixing or ballast strategy against wind uplift on tall or open sites
- Not a below-grade or tanking membrane — it is designed for exposed roof waterproofing, not buried structural waterproofing
Selection & best practice
Prepare a clean, dry, sound and smooth substrate, removing debris and sharp edges that could puncture the sheet, and confirm the deck falls drain correctly before laying. Choose the fixing method — mechanically fixed, fully adhered or ballasted — to suit the deck type and site wind exposure, and set out rolls to keep seams away from ponding areas. The critical step is welding: dial in the hot-air welder temperature and travel speed on trial welds for the day’s ambient conditions, keep the weld zone clean, and probe-test every finished seam for continuity. Dress all upstands, drains and penetrations with welded membrane flashings rather than sealant alone. Store rolls upright, protected from prolonged sun and mechanical damage, and let the crew’s welder settings be re-checked whenever temperature or humidity shifts materially through the day.
Specifications
| Product type | Single-ply, non-reinforced homogeneous TPO (thermoplastic polyolefin) roofing membrane |
| Base polymer | Thermoplastic polyolefin (ethylene-based polyolefin alloy) |
| Thickness options | 1.2 mm, 1.5 mm and 2.0 mm |
| Roll width | 1.2 m and 2.0 m |
| Solar reflectance (SRI) | >100 (white) |
| Cold flexibility | Pass at -40C |
| Seaming method | Hot-air welded (thermally fused seams) |
| Installation methods | Mechanically fixed, fully adhered or ballasted (loose-laid) |
| Recyclability | 100% thermoplastic, recyclable at end of life |
Industry use cases
Commercial and industrial roofing
Wide warehouse, factory and mall roofs where flame-free welded seams give a reliable watertight skin over long, exposed spans.
Cold chain and cold storage
Refrigerated warehouses and cold-store roofs that need a membrane staying flexible and crack-free at very low temperatures.
Green and sustainable buildings
LEED-oriented projects using the reflective white cool-roof surface and recyclable sheet, including root-resistant green-roof build-ups.
Rooftop solar
Ballasted PV arrays laid over the membrane on large flat roofs, pairing a cool deck with clean energy generation.
Roof renovation
Overlay or replacement of tired bituminous felt roofs, swapping open-torch work for a lighter, flame-free single-ply system.
Frequently asked questions
Is ShaliTPO HG reinforced?
How are the seams joined?
What thicknesses and roll widths are available?
Can it be used under a rooftop solar array or a green roof?
How does it compare with torch-applied bituminous membranes?
Does Space Arc supply and apply it?
How we position STP ShaliTPO HG
Within the STP ShaliTPO family, HG is the entry-point non-reinforced homogeneous grade; step up to ShaliTPO PR (polyester-scrim reinforced) or ShaliTPO GR FB (glass-scrim, fleece-backed) when higher tensile strength, puncture resistance or a fleece-backed fully-adhered build-up is required, or to ShaliTPO HG FB where a fleece backing suits the substrate. For projects that call for a different waterproofing technology, Space Arc also carries torch-applied bituminous membranes and liquid-applied systems from other brands — Fosroc Proofex Torchseal for below-grade and structural tanking, and acrylic/PU liquid membranes such as Dr. Fixit and Fosroc Brushbond for exposed terraces and wet areas — letting us match the membrane to the deck rather than force one system onto every roof.
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