Fosroc Proofex Self Adhesive PR 15
A 1.5 mm cold-applied, polyester-reinforced self-adhesive bituminous membrane that bonds continuously to primed substrates for fast, torch-free waterproofing of roofs, basements and raft slabs.
What is it?
A 1.5 mm thick, cold-applied self-adhesive sheet membrane of polymer-modified bitumen internally reinforced with polyester and faced with a cross-laminated polyethylene (PE) film. It bonds to a Proofex Tack Coat-primed substrate with no torch or hot bitumen.
Where is it used?
Medium-to-large roof slabs (domestic, commercial, industrial), basements and raft slabs, roof gardens (where root resistance is not required), and external faces of cut-and-cover tunnels. Suitable on concrete, masonry, GI, aluminium, asbestos sheet and timber.
Why use it?
Eliminates open-flame torching, cures no waiting time, develops high tensile strength (750 N/5cm) and puncture resistance (580 N), withstands 60 m hydrostatic head, and is fast to lay—ideal for tight construction programmes in Indian conditions.
How is it applied?
Prepare and dry the substrate, apply Proofex Tack Coat and allow to go tack-free, peel the silicone release paper, press the membrane down with 75 mm side and 150 mm end laps (staggered), then protect immediately with protection board or sand/cement screed per BS 8102:2009.
About Fosroc Proofex Self Adhesive PR 15
Fosroc Proofex Self Adhesive PR 15 is a cold-applied, self-adhesive sheet waterproofing membrane engineered for building and civil-engineering structures where a continuously bonded, torch-free system is preferred. Structurally, it is a 1.5 mm composite: a polymer-modified bitumen adhesive layer internally reinforced with a polyester carrier and laminated to an outer cross-laminated polyethylene (PE) film. The underside of the bitumen adhesive is protected by a siliconised release paper that is peeled away immediately before the sheet is rolled onto a primed substrate. Because the adhesive bonds on contact, the membrane forms an intimate, fully adhered seal that resists lateral water migration—a meaningful advantage over loose-laid systems where any breach can track water across the slab. The product carries the Fosroc India reference INDIA/2015/0837/A and is supplied with its companion primer, Proofex Tack Coat. For Indian contractors, consultants and developers, PR 15 sits in the self-adhered bituminous membrane family alongside heavier and pre-applied variants in the Proofex range, and is positioned for projects that want the reliability of a reinforced bitumen sheet without the fire risk, fumes and skilled-labour dependency of torch-on (APP/SBS) felts. Space Arc Engineering supplies and applies PR 15 as an authorised Fosroc distributor across Delhi NCR and Pan-India, with technical back-up on substrate priming, detailing at upstands and corners, and protection sequencing.
The technical insight
The performance of PR 15 rests on its layered construction rather than membrane thickness alone. The polyester reinforcement is what delivers the high in-plane tensile strength (750 N/5cm longitudinal, 600 N/5cm transverse to ASTM D638) and tear resistance (≈395/390 N/5cm to ASTM D5147), allowing the sheet to bridge minor substrate movement and resist site handling damage. The PE facing provides a tough, abrasion- and puncture-resistant top surface (580 N puncture to ASTM D4833/5494) and an initial UV/mechanical shield until the protective screed or board is placed. A 115°C softening point (ASTM D36) keeps the bitumen dimensionally stable on warm Indian roof decks, while cold flexibility down to -5°C (ASTM D836, no cracks) covers cooler climates. Critically, the system is designed for adhered—not just covered—waterproofing: lap adhesion of 2.2 N/mm (ASTM D1000) and a tested hydrostatic head of 60 m of water (ASTM D5385) with no leakage under DIN 52123 mean the laps and the sheet itself are the watertight barrier. The single most common failure mode is poor priming or trapped air, which is why Proofex Tack Coat must be applied and allowed to go fully tack-free, and the sheet pressed down with no air pockets. Note that the Fosroc datasheet narrative quotes an elongation figure of 2000% (ASTM D146-04) while the properties table lists 40–41% elongation (ASTM D638); the lower, reinforced-composite values are the engineering-relevant figures for design, and the 2000% reference appears to relate to the unreinforced bitumen compound. Always confirm against the current project-specific TDS.
Where it is used
- Waterproofing of medium-to-large roof slabs on domestic, commercial and industrial buildings
- Tanking of basements and raft slabs (horizontal and vertical faces)
- Roof gardens and planted decks where resistance to root penetration is not a requirement
- External waterproofing of cut-and-cover tunnels and below-ground structures
- Damp-proofing over GI, aluminium and asbestos corrugated sheets using the stick-on application
- Waterproofing across mixed substrates—concrete, masonry, timber and metal—within a single deck
Key advantages
- Cold-applied and self-adhesive—no torch, no LPG, no hot bitumen kettle, lowering fire risk on site
- Fast to lay and immediately bonded, compressing waterproofing time on tight programmes
- Polyester reinforcement gives high tensile strength (750 N/5cm) plus strong tear and puncture resistance
- Fully adhered to the substrate, restricting lateral water tracking if the sheet is later breached
- Accommodates thermal movement and remains flexible at low temperature (no cracks to -5°C)
- Tested to 60 m hydrostatic head with no leakage—suited to below-ground tanking
- Bonds to a wide range of primed substrates including concrete, masonry, GI, aluminium and timber
- No associated health hazards in use and no open-flame fumes, easing site HSE compliance
Limitations & considerations
- Requires Proofex Tack Coat priming; surfaces left longer than 24 hours before membrane application must be re-primed
- Application temperature limited to 5°C–50°C; below 15°C the membrane back may need slight warming and warm storage (>20°C)
- Not suitable where active root resistance is required—use a root-resistant system for intensive green roofs
- Must be protected immediately after laying (protection board or sand/cement screed per BS 8102:2009) against UV and mechanical damage
- Substrate must be dry and free of frost, laitance and contamination—not a wet-substrate or negative-side product
- Self-adhesive bond quality is installer-dependent; trapped air or contamination at laps compromises watertightness
- 12-month shelf life and horizontal storage (max one pallet high) needed to preserve roll quality
- The flexible-but-reinforced composite resists movement but is not a high-extension liquid system for severely cracking substrates
Selection & best practice
Confirm the substrate is sound, dry and free from frost, laitance and contamination, with all projecting nibs removed and re-entrant corners filleted with sand/cement mortar; pre-treat internal and external corners and upstands with Proofex Corner Pieces before sheeting. Apply Proofex Tack Coat at 3–6 m²/litre and allow it to dry tack-free—re-prime any area left longer than 24 hours. Peel the silicone release paper progressively and press the PE-faced membrane firmly onto the primer, working out all air so it bonds continuously; maintain a minimum 75 mm side lap and 150 mm end lap with all laps staggered. On vertical or inclined faces, work from the lowest level upward so laps shed water. In cool weather (below 15°C) store rolls above 20°C and slightly warm the membrane back to ensure immediate adhesion. Protect the completed membrane straight away with protection board or a sand/cement screed in line with BS 8102:2009, and keep all products away from ignition sources during storage and use.
Specifications
| Product type | Cold-applied self-adhesive polymer-modified bitumen sheet membrane, polyester-reinforced, PE-topped |
| Membrane thickness | 1.5 mm (±5%) — UEAtc M.O.A.T. 30 |
| Nominal weight | 1.68 kg/m² — UEAtc M.O.A.T. 30 |
| Tensile strength (longitudinal) | 750 N/5cm — ASTM D638 |
| Tensile strength (transverse) | 600 N/5cm — ASTM D638 |
| Elongation (longitudinal / transverse) | 40% / 41% — ASTM D638 |
| Tear resistance (long. / trans.) | 395 N/5cm / 390 N/5cm — ASTM D5147 |
| Softening point | 115°C — ASTM D36 |
| Cold flexibility (0°C to -5°C) | No cracks observed — ASTM D836 |
| Resistance to water pressure | No leakage — DIN 52123 |
| Hydrostatic head resistance | 60 m of water — ASTM D5385 |
| Lap adhesion strength | 2.2 N/mm — ASTM D1000 |
| Puncture resistance | 580 N — ASTM D4833/5494 |
| Laps | 75 mm side/edge lap; 150 mm end lap; all laps staggered |
| Primer | Proofex Tack Coat — coverage 3–6 m²/litre |
| Application temperature | 5°C – 50°C (warm membrane back below 15°C) |
| Flash point (membrane / Tack Coat) | >65°C / >38°C |
| Protection standard | Protect immediately per BS 8102:2009 |
| Roll size | 15 m long x 1 m wide; Tack Coat in 20 L & 200 L drums |
| Shelf life / storage | 12 months; cool dry store, horizontal, max one pallet high |
| Datasheet reference | Fosroc India INDIA/2015/0837/A |
Industry use cases
Residential & commercial roofing
Cold-applied waterproofing of medium-to-large RCC roof slabs without open-flame torching, then protected with a sand/cement screed—well suited to occupied buildings and fire-sensitive sites in Indian cities.
Basements & raft foundations
Continuously bonded tanking of raft slabs and basement walls on the positive (water) side, leveraging the 60 m hydrostatic-head rating for below-ground structures in high water-table zones.
Infrastructure & tunnelling
External waterproofing to cut-and-cover tunnels and buried structures where a tough, polyester-reinforced adhered membrane resists construction traffic and backfill loads.
Industrial buildings & metal decks
Stick-on damp-proofing over GI, aluminium and asbestos corrugated sheeting for warehouses and sheds, exploiting the membrane’s adhesion to primed metal substrates.
Landscaped & podium decks
Waterproofing to roof gardens and planter areas where root resistance is not specified, combined with separate root-barrier and protection layers as required.
Frequently asked questions
Is Fosroc Proofex Self Adhesive PR 15 a torch-applied membrane?
Do I need a primer, and which one?
What thickness and roll size does PR 15 come in?
How much water pressure can it withstand?
What laps and overlaps are required?
How does PR 15 compare with PR 20 and torch-on alternatives?
How we position Fosroc Proofex Self Adhesive PR 15
Within the Fosroc waterproofing range, Proofex Self Adhesive PR 15 is the workhorse 1.5 mm self-adhesive bituminous membrane, sitting one step below the heavier Proofex Self Adhesive PR 20 (2.0 mm) and alongside specialised options such as Proofex Self Adhesive Geotext. For pre-applied, fully bonded basement tanking under raft slabs, Fosroc’s Proofex Engage (an HDPE pre-applied membrane that bonds to subsequently poured concrete) is often the better engineered choice, while liquid-applied and crystalline systems in the Fosroc range suit complex detailing or integral concrete waterproofing. PR 15 is best specified where the programme benefits from a flame-free, fast cold-applied sheet over primed concrete, masonry or metal decks. Against the wider Indian market, credible alternatives include Sika’s self-adhesive and torch-on bituminous membranes (SikaBit / Sikaplan families), STP’s bituminous membrane range, and Dr. Fixit (Pidilite) self-adhesive and APP membranes for residential roofing; MBS (Madhusudan/STP-aligned and similar specialist brands) competes in the torch-on felt segment. The right selection depends on substrate, water head, fire constraints and detailing complexity. As an authorised Fosroc distributor and applicator, Space Arc Engineering can validate the choice between PR 15, PR 20 and Proofex Engage for a given project and provide the matching primer, corner pieces and protection materials.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.