Polyester membrane application

In a bathroom wet area

Step 1. The area to be waterproofed shall be dry and clean. Door threshold water stop is to be set with fall to drainage as requirements per AS-3740 and installed with FC polyurethane sealant.

 All lumps and bumps shall be removed and voids shall be filled to create a smooth surface for membrane installation with no sharp edges.

Floor to wall sheet junctions are to be caulked with construction grade Fast Cure polyurethane sealant.

The 225g fibreglass lineal strip roll shall be bedded into the uncured polyurethane sealant cove of the wall to floor junction with the minimum upturn of 150 mm.

Step 2. Measure and cut 300g Meter wide fiberglass matting from your roll to fit the area, lay the metre wide matting with the fibreglass overlapping itself across the floor by 70 mm and onto the wall to floor junction by 30 mm.

Step 3. According to room substrate temperature

 Mix the M.E.K.P hardener thoroughly into resin in a container and apply the resin to the fibreglass matting, carefully but make sure to thoroughly wet out and mold the resin into the fibreglass using a roller and brush.

Hot temperatures require 1 % Catalyst ratio to resin volume.

Cold temperatures may require 2 - 4 % Catalyst ratio to resin volume. 

Step 4. Once fibreglass and resin hardens into a uniform waterproof material- Usually within 60 minutes, dependant on substrate temperature, check your waterproofing for consistency.

Step 5. If you are not 100 % happy with the waterproofing thickness simply repeat the inter laminar process to re-layer the tray.

Step 6. Inter laminate water stop angles or water diverters in shower areas and carry out reinforcement of areas that are potentially weak points and that are at risk of movement.

Step 7. When you are 100% happy apply the finishing waterproof coat.

Between layers and coatings.

(Builders plastic must be laid onto of freshly cured membrane floor to prevent contamination and shoes sticking when re- dressing the next fibreglass layer) and while inter laminating or top coating the new floor surface.

mixing ratio of catalyst to Polyester resin is 1 % of resin volume. For example, 1 litre of Polyester resin will require 10- mls of catalyst.

Before mixing any resins or catalyst/hardeners ensure that you are using the correct

PPE equipment recommended.

• Safety glasses

• Breathing respirator

• Latex/Nitrile disposable gloves

• Create a well-ventilated work area by using an extraction fan in confined spaces.

• Always use ventilation and a combination filtered mask that is approved for Organic Peroxide when mixing and applying Resin/MEKP Catalyst with fiberglass in confined space.

•  If contact is made with skin clean off excess resin/MEKP Catalyst with rag and wash skin with soap and water to prevent burns.

•  If contact is made with eyes immediately flush out resin/MEKP Catalyst with water for up to 10 minutes or as long as it takes.

• If swallowed do not induce vomiting, rinse mouth out with water and call a physician immediately.

• If overcome by fumes, move persons into fresh air.

• Resin spills: Clean up with inert absorbent material.


It is important that the catalyst and resin is mixed thoroughly before use to reach a full thermoset cure!

Pot life of mixed resin and MEKP catalyst is around 20 minutes, (Meaning) only mix what you can use in that time frame, starting with a small roller, wet out perimetres and then continue to pass over the area a second and third time wetting out and mold and softening fibreglass with roller and brush until the layer is uniform.




Squeezing out catalysed resin from rollers and brushes before mixing the next container of resin will ensure the resin filled brush/ rollers remain at the beginning of the exothermic reaction cycle.


The exothermic reaction between the mixed hardener and resin causes the fibreglass to soften, usually within a few minutes of wetting out the fibreglass matting reinforcement.

Use the roller to saturate the resin through the fibreglass and use a brush to shape the fiberglass matting tightly into the edges/corners, taking care to remove entrapped air bubbles.

The subsequent layering of fiberglass will give the installer a higher degree of membrane strength.