Thompson's Water Seal Thompson's Water Seal
Thompson's One Coat Water Seal

Product Information

Thompson's Water Seal utilises hydrophobic technology to deliver invisible protection against water damage. The deep penetrating formulation travels deep into exterior dry porous surfaces to form a breathable membrane that allows moisture vapour inside the substrate to evaporate whilst protecting against water penetration and damage. Thompson's Water Seal has a unique formulation which, unlike some waterproofers, penetrates the surface therefore waterproofing even after the initial beading is gone. It will not be destroyed by ultraviolet light and is long lasting even under heavy moisture conditions. Assuming application instructions and coverage guidelines are adhered to it provides effective water repellency for years.


Suitable for use on brick, concrete, stone and wood. For exterior use only


Up to 10m/litre depending on porosity of the substrate


Drying times will vary depending on the absorbency of the surface and weather conditions. See technical datasheet for detailed dry times





1Litre, 2.5Litre, 5Litre


Very High

Very High VOC


Not suitable for use on plywood


For maximum performance ensure the surface to be treated is clean, dry and free from mould and fungal growth and any other coatings that may interfere with the penetration of Thompson's Water Seal. It will not fully penetrate wet or damp surfaces. Carry out any repairs and fill any surface cracks prior to treatment.


Thompson's Water Seal can be applied by brush, roller, dipping or low pressure spray. For best results both surface and air temperature should be above 40F/5C. On vertical surfaces, saturate well, working from the bottom up. On horizontal surfaces saturate well and after 15 minutes remove puddles by redistributing to dry areas. For maximum protection apply two coats. On masonry the second coat may be applied as soon as the first coat has soaked into the surface. On other substrates allow at least 24 hours between coats. Very porous substrates may require additional coats. Allow 3 days before painting over with oil based paint or stain and 30 days for water based paint or stain.

Clean Up

Clean brushes, rollers and other equipment immediately after use with white spirit or brush cleaner. Remove as much product as possible from application equipment before cleaning.

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How To Guide

How to image for sealing and waterproofing brickwork concrete and stone

Read our How To Guide for sealing and waterproofing brickwork concrete and stone.

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Download technical data sheet