How do I apply a paint, coating or
liquid applied waterproofing membrane?

This article explains the important steps required to ensure that a paint, coating or liquid applied waterproofing membrane is applied properly. Using the best preparation and application techniques will help you to get the best lifetime and protection from your coating.

Key Takeaways

  • Always refer to the manufacturer's guidelines.
  • Good surface preparation is essential for adhesion of the coating.
  • Remove old flaking paint, dirt, grease and organic growth.
  • If necessary apply a primer to seal the surface.
  • Solvent based products require application onto a dry surface.
  • Use a brush, spray or roller to apply the coating evenly.
  • Apply the number of coats as recommended by the manufacturer.
  • Wear protective equipment, ensure adequate ventilation and follow manufacturer's health and safety guidance.

Application depends upon the exact nature of the product. In all cases refer to the manufacturer's guidelines.

Before starting, ensure that all surfaces and items that should not get coated are covered with dust sheets or moved away. If you are applying a coating using spray equipment outside be aware of windy conditions that could blow the product onto nearby surfaces.

Surface Preparation

Whatever type of building or construction the application is for, whether it be for roofs, floors, walls or foundations, good surface preparation is vital when applying any paint, coating or waterproof product. If the surface (substrate) is not adequately prepared the coating could lose adhesion. Any coating is only as good as the surface that it has been applied onto.

General guidelines for surface preparations are as follows: Remove old flaking paint, loose particles and organic growth, which should first be treated with a fungicide. Well-bonded paints might not need to be removed but beware of old paints which have lost adhesion in some places but appear sound in others. Power washing may be recommended. Repair surface defects. Ensure all surfaces are clean, dry and firm before application.

Priming the Surface

Priming - in certain circumstances a primer should be applied, for example to consolidate friable surfaces, to seal porous surfaces, to block any bleed from bituminous surfaces, or if corrosion is present on steel surfaces.

Some products should be stirred before application whilst other products must not be stirred. Some products can be thinned with a suitable solvent before application whilst other products must not be thinned. Solvent based products must not be thinned with water and vice-versa.


Most coatings and waterproofing products can be applied by brush, spray or roller and should be applied evenly. The thickness of the coating and the number of coats will depend upon the paint, coating or waterproofing membrane.

Most products cannot be applied if the temperature is too low or if rain is expected. Solvent based paints, coatings or waterproofing products cannot be applied onto a damp or wet surface.

Worker painting a wall using a roller.
Paint and liquid membranes can be applied using by brush, roller, sqeegee or spray

Cleaning and Disposal

Clean brushes, rollers and spray equipment with water or a proprietary solvent immediately after use.

Dispose of any remaining product according to local authority regulations. Always recycle if possible. Paints, coatings or waterproofing products should NEVER be poured into water courses.

Health and Safety

Always wear suitable protective equipment, such as overalls, gloves and goggles. Always provide as much ventilation as possible. Some products may require the use of ventilators or breathing equipment during application. Dust masks should be worm whilst carrying out surface preparation where dust may be created. Always refer to the manufacturer's health and safety advice.

If you are working up a ladder check first that the ladder is in good condition. Ensure that it is level, positioned securely and that you will not need to overreach to get to your paint or the surface. Always wear secure footwear when going up a ladder. Detailed information about ladder safety can be found in this leaflet from the Ladder Association and HSE.


Please note that any information or advice on this page is supplied in good faith and that while we make every effort to ensure that it is accurate, helpful and up to date, it is given without commitment or guarantee. We always recommend that trials are carried out prior to undertaking any work or contracts.

Please remember that orders have to be above our minimum size quantity.