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Grants WPM 400 Waterbased P.U. Under Tiles Membrane 15 Litre

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$149.95 each
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Grants WPM 400 is a Grey Class III fibre reinforced water-based polyurethane membrane that has been designed for a range of waterproofing applications for under Tile. It can be used for wet areas, balconies and deck areas that are going to be tiled and not left exposed. It has excellent adhesion to concrete, masonry, renders and internal cement sheeting and plaster board sheeting.

All porous surfaces must be primed with Grants PR 100 primer and non-porous substrates such as external cement sheeting, e.g. Scyon, must be primed with a moisture barrier. As a wet area membrane requires a suitable bond breaker, at all substrate junctions it is advised to use FC Polyurethane sausage.

It is not designed for use as an exposed membrane.


    •A minimum of 2 coats is recommended to be applied at a total minimum coverage of 1.5 Litres/m2.
      •1mm dry film thickness is recommended for all applications wall and floor.



Online FREE delivery for metro standard orders over $100 in VIC, NSW, SA, and QLD.

All other online standard orders have either a pallet delivery fee of $89 or a parcel delivery fee of $10.

Delivery fees are automatically calculated at checkout based on the items in your order and postcode.

Please click here to view the table below for estimated online standard order delivery fees and time frames as well as non-standard delivery fees and time frames.


We offer FREE click and collect for all online orders in Metro Stores.

If the items in your order are in stock in your state, they can be available to collect from store or be ready to dispatch within 2-3 business days.

Once you place your online order, you will receive an email notification or a phone call from one of our friendly customer service team members within 48 business hours to let you know the date that your order can be picked up in store.

If you have any questions please visit or call your local National Tiles store, submit an online enquiry or call 1300 733 000 between 9 AM to 5 PM AEST on business days.


Product Specifications



Technical Data & Catalogue

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Product & Safety Data Sheet

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Where To Use

It can be used for wet areas, balconies and deck areas that are going to be tiled and not left exposed.

Form / Consistency



A minimum of 2 coats is recommended to be appliedat a total minimum coverage of 1.5 Litres /m2

Waiting time between coats

2- 4 hours

Waiting before laying coating material

24-48 hours

Water Vapour Transmission


Tensile Strength (N/mm²)

> 1.2mpa