F. Pacaña Street, Barangay Tisa Cebu City, Cebu PH 6000 (032) 340 - 8813 almichmarketing@gmail.com

Proofex GPE


Cold applied polymer modified bitumen waterproofing sheet membrane


To provide a vapour-proof and waterproof membrane for building and civil engineering structures. Typical applications include basements, ground slabs, roofs, foundations, lift pits and subways.


  • Waterproof and vapour proof
  • Cold applied
  • 1.5 mm nominal uniform thickness
  • Good adhesion to primed concrete surfaces
  • Excellent adhesion to concrete substrates


Proofex GPE is a cold applied, self adhesive sheet waterproofing membrane consisting of a polymer modified bituminous compound and a polyethylene surface film to assist in handling. The adhesive surface is protected by a release paper which is removed before application.


Technical Support

Fosroc offers a comprehensive range of high performance high quality, construction products. In addition to a wide range of quality products, Fosroc offers a technical support package to specifiers and contractors which includes assistance with product selection and technical advice from staff with unrivalled experience in the industry.

Design criteria

The Proofex GPE membrane should be protected using Proofex Protection Board or a sand/cement screed for horizontal applications prior to further construction. Proofex Protection Board should be spot bonded to the Proofex GPE using Plastiseal.

As an enhanced drainage protection board, Proofex Sheet drain can be bonded to Proofex GPE membranes using Plastiseal.

Proofex Primer may be omitted where Proofex GPE is to be used as DPM to a horizontal slab beneath Proofex Protection Board or a sand/cement screed. All internal/external angles should be reinforced with a 300 mm wide strips of Proofex GPE membrane. Where practicable a 25 mm chamfer should be provided to all external angles prior to the application of the reinforcement strip.


There are no special requirements; however any damage should be repaired by exposing the damaged area, cleaning the surface and applying a patch of Proofex GPE over the damaged area extending 300 mm past the edge of the damage.

Specification clauses

Supplier specification

Waterproof membrane, where shown on the drawing shall be Proofex GPE, self-adhesive membrane obtained from Fosroc Ltd. Proofex GPE shall be applied in accordance with the current technical data sheet.

Performance specification

The waterproofing membrane shall be a 1.5mm thick self adhesive sheet membrane comprising of a polymer modified bitumen layer internally reinforced with fibreglass fleece, bonded on to an outer surface of polyethylene film. The polymer modified bitumen shall have an elongation in excess of 2000% when tested in accordance with ASTM D412.

Application Instructions

Surface preparation

All concrete surfaces must be wood float or shutter finished, free from cavities and projections. All damaged concrete should be made good. Brick and block surfaces shall be made sound and all mortar joints flush pointed. Rough brick or open textured blocks shall be made smooth with a sand/cement render. All surfaces must be clean, dry and free from dirt, frost, mould release agents and curing compounds.


Apply Fosroc Proofex Primer by brush. Ensure complete coverage and allow to dry. Very porous brick, block and rendered surfaces may require extra coats of Fosroc Proofex Primer. Only prime an area to which the Proofex GPE can be applied the same day.

Note: Fosroc Proofex Primer may be omitted where Proofex GPE is to be used on horizontal slabs as a damp proof membrane beneath a protective screed.

Angles and corners, cement/sand mortar strips should be used at all wall to floor junctions. The Cement/Sand Mortar should be fixed using 6 mm beads of Fosroc Plastiseal applied to the vertical and horizontal faces approximately 30 mm away from the junction.

Internal and external corners should incorporate Fosroc Proofex corner pieces which should be fixed using Fosroc Plastiseal as an adhesive.

All internal and external angles should be reinforced with a 300 mm wide strip of Proofex GPE. Where possible a 25 mm x 25 mm chamfer should be provided to external angles.

Vertical Application

Proofex GPE should be applied to ensure that all end laps are weathered

Cut Proofex GPE to length allowing an extra 150 mm for each end lap.

Starting at the top of the wall, offer up the Proofex GPE to the tack coated surface. Remove the release paper from the start of the roll. Progressively peel back the release paper and press the membrane firmly into position working from the centre outwards to expel all trapped air.

To obtain a weathered lap it may be necessary to retain the last 500 mm of release paper on the roll. Only when the next drop or corner detail is being completed, remove this remaining piece of release paper and smooth down onto the underlying Proofex GPE. The next roll or length should be aligned against the previously applied piece allowing for the 75 mm (or as specified) edge lap and 150 mm end lap. The selvedge release film should be removed immediately prior to the lap being made.

Vertical areas should be protected with Proofex Protection Board or block work as soon as possible after application. The backfill should take place immediately after the membrane and protection have been installed.

Horizontal application

Unroll the complete roll of Proofex GPE and align edge with a chalk line.

Load at one end and half way along the membrane to maintain alignment. Roll up the other half working back towards the midpoint.

Carefully make a cut across the release paper only of the rolled up Proofex GPE. Take care not to cut through the membrane.

Ease the release paper away from the bitumen compound and start to unwind the roll by a steady pull on the release paper.

As the roll unwinds, press the Proofex GPE firmly onto the surface using a broom, working from the centre outwards to expel all trapped air.

Repeat this process with the second half of the roll. The next roll or length should be aligned against the previously applied piece allowing for the 75 mm (or as specified) edge lap and 150 mm end lap. All edges and laps should be rolled to ensure proper contact and bond of the laps. All overlaps on vertical and slopping surfaces must be weathered.

Damaged areas of Proofex GPE must be repaired with a minimum 300 mm x 300 mm patch to ensure that there is at least 150 mm overlap of Proofex GPE all around the damaged area. If work is continued from one day to the next, all exposed edges must be sealed by rolling to prevent water penetration.

All horizontal areas of Proofex GPE should be protected as soon as possible after application with Proofex Protection Board or a sand/cement screed.


Proofex GPE is not a load bearing DPC material. Where membrane continuity is required through a wall, Proofex GPE should be lapped onto the edges of a suitable DPC material.

Proofex GPE should not be used in situations subject to fuel or oil spillage or in soils heavily contaminated with fuel oils or solvents




Proofex GPE has a shelf in excess of 12 months

Store vertically in cool, dry conditions.


Health and Safety

Proofex GPE Membrane: There are no known health hazards associated with Proofex GPE in normal use.

Proofex Primer: Flammable. Keep away from sources of ignition. No smoking. Harmful by inhalation, in contact with skin and if swallowed.

Avoid contact with skin and eyes and inhalation of vapour. Wear suitable protective clothing, gloves and eye/face protection. Use only in well ventilated areas.


Proofex GPE and Protection Board are flammable. Keep away from sources of ignition. Do not smoke in the presence of these products. Proofex Primer contains volatile flammable solvents. Use only in ventilated areas, well away from any ignition source.