About Fosroc Proofex OGP

Fosroc Proofex OGP is the standard (non-reinforced) grade of Fosroc’s Proofex TPO/FPA single-ply membrane range, designed for the waterproofing of above-ground structures such as exposed roofs, podium decks, terraces and garden/green roofs. It is a thermoplastic polyolefin / flexible polypropylene alloy sheet produced by extrusion of granules made by incorporating ethylene-propylene rubber into a polypropylene matrix with additives suited to the membrane type. The sheet is deliberately two-toned, grey on the top surface and black on the underside, so that any cuts, scuffs or damage during installation are immediately visible and can be repaired before the system is covered. Unlike PVC membranes, the formulation contains no plasticisers that can migrate or leach out, no VOCs and no toxic fumes when welded, and the material is recyclable. Within the wider family, Proofex OGP is the general-purpose standard membrane, Proofex ORG is the polyester-reinforced grade and Proofex OFB is the fully bonded grade used where full adhesion to the deck is specified; OGP also serves as the membrane used for welded cover strips over butt joints and for site-fabricated detailing alongside the other grades. For Indian projects, Space Arc Engineering supplies Proofex OGP as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, with technical support for specification, method statements and trained welding crews. The range is covered by BBA Certificate 15 5242 (Proofex OGP/ORG/OFB) and is detailed in the Fosroc TPO Application Guidebook, which sets out substrate preparation, fixing, welding parameters and on-site quality control. A practical advantage on insulated roofs is that no separation geotextile is required at the EPS insulation interface, simplifying the build-up. With its broad welding temperature window and resistance to weathering, the system is well suited to demanding Indian roof and podium applications where a long, low-maintenance service life is required.

The technical insight

Proofex OGP is a TPO/FPA alloy rather than a plasticised PVC, and that distinction drives its performance. Because the flexibility comes from the polymer alloy (EPDM rubber dispersed in polypropylene) and not from added plasticisers, there is nothing to leach out or volatilise over time, so the sheet stays flexible and dimensionally stable for decades and is compatible with EPS insulation without a separation layer. The standard OGP grade is offered in 1.2, 1.5, 1.8 and 2.0mm thicknesses (to EN 1849-2), letting the specifier match sheet weight and puncture margin to traffic and exposure. Jointing is by hot-air welding, which fuses the overlapping selvedges into a homogeneous, monolithic seam stronger than the parent sheet in peel tests, instead of relying on adhesive bond. The membrane’s wide weldability window (typically hot-wedge/hot-air around 280-650 degC, speeds up to ~12 m/min on automatic equipment, minimum 50mm single-weld seam) tolerates site temperature swings and even allows welding after prolonged outdoor exposure once the oxidised surface is solvent-wiped, which is a real benefit on phased Indian sites. The black/grey two-tone is a built-in QC aid, and root resistance (FLL) plus UV durability make OGP equally valid under green-roof build-ups and fully exposed.

Where it is used

• Waterproofing of exposed flat and low-slope concrete roof decks
• Podium decks and intermediate slabs over occupied/parking spaces
• Garden roofs and green/landscaped roofs requiring root resistance
• Terraces, balconies and walkway decks above ground
• Welded cover strips over butt joints and roll ends in TPO systems
• Site-fabricated upstands, skirtings, internal/external corners and pipe penetrations
• Overlay/refurbishment waterproofing compatible with bitumen for roof overlays

Key advantages

• TPO/FPA chemistry with no plasticisers, no VOC and no toxic fumes when welded
• Hot-air welded seams give homogeneous, watertight joints stronger than glued laps
• BBA-certified (Cert 15 5242) for exposed and garden/podium roofs
• High resistance to UV, weathering and root penetration (FLL pass)
• Grey-top / black-underside design makes installation damage easy to spot and repair
• No separation geotextile needed at the EPS insulation interface, simplifying build-up
• Broad welding temperature window, so seams remain reliable across site conditions
• Recyclable, inert and suitable for use in contact with potable water (BS 6920 on relevant grades)
• Available in multiple thicknesses (1.2/1.5/1.8/2.0mm) to suit exposure and traffic

Limitations & considerations

• Requires skilled operatives and hot-air welding equipment; not a brush/roller-applied coating
• Seam quality depends on correct temperature/speed/pressure settings, so on-site trial welds and continuous monitoring are essential
• Substrate must be sound, dry, free of cavities, projecting nibs and running water before laying
• Oxidised membrane after prolonged outdoor exposure must be solvent-wiped before welding
• As a single-ply sheet it needs careful detailing at penetrations, corners and upstands using matching Proofex ancillaries
• Mechanical damage during following trades must be probed and patch-welded before cover
• Primarily an above-ground roof/podium membrane, not a substitute for cementitious tanking in below-ground/hydrostatic conditions

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Proofex OGP

Proofex OGP sits in Fosroc’s single-ply roofing line as the general-purpose standard membrane, paired with Proofex ORG (reinforced) and Proofex OFB (fully bonded), and supported by Fosroc ancillaries such as Proofex internal/external corners, Proofex Metal Strip, Proofex OGP/OFB adhesives and Nitoseal MS60 sealant. It is most appropriate where a contractor wants a welded, plasticiser-free TPO system for exposed roofs, podiums and green roofs rather than a liquid-applied or torch-on bituminous solution; for below-ground or hydrostatic tanking, Fosroc’s Proofex Engage or cementitious systems are the better reference. In the Indian market, comparable single-ply and membrane alternatives a consultant may evaluate include Sika Sarnafil and Sikaplan TPO/PVC membranes, Soprema/STP (Supreme/STP) APP and TPO membranes, and for liquid-applied roof systems, Dr. Fixit (Pidilite) and MYK Arment/MBCC-style polyurethane and acrylic coatings. Against torch-on bitumen and liquid coatings, OGP’s advantages are welded homogeneous seams, no plasticiser migration and BBA-certified root and UV durability; the trade-offs are the need for skilled welding labour and equipment and careful detailing. Space Arc Engineering positions Proofex OGP as a premium, long-life exposed-roof and podium membrane backed by authorised-distributor supply and trained applicators across Delhi NCR and Pan-India.

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