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Watco Liquid Roof Membrane

Reinforced waterproof protection for flat roofs

  • Ultra-tough, UV resistant membrane
  • Fibre-reinforced for extra protection and durability
  • Highly flexible – won’t split with roof movement
  • Can be applied to damp surfaces
Frequently bought together


Watco Liquid Roof Membrane is a roller applied coating system designed to protect flat and pitched roofs. Watco Liquid Roof Membrane can be easily applied around existing pipe work and protrusions. With an inert fibre reinforcement it protects around these areas where the risk of water leakage is high. Two coats will cure to give a tough, 1-1.5mm thick sealing membrane. Its high elasticity allows the roof to move without the membrane splitting or cracking. 


  • Seamless finish
  • UV stable
  • Moisture cured. Can be applied to slightly damp surfaces
  • Membrane moves with the roof to reduce splitting
  • Seals areas surrounding roof protrusions
  • Allows substrate to breathe and release vapours
  • Suitable for flat and pitched roofs
  • Cold applied – no heating equipment required
  • Convenient single pack
  • Touch dry in 4 hours (at 20°C)


Suitable for Concrete, old asphalt or similar type roofs
Finish Low sheen, smooth
Interior or Exterior Exterior
Composition Single pack, moisture curing polyurethane
Coverage 5-7m² per 5L per coat and 12-18m² per 12.5L per coat
Number of coats 1 or 2
Dry film thickness 900 microns per coat
Curing time 8 hours at 20°C
Minimum application temperature 10°C


Surface preparation

Inspect entire surface to assess soundness of existing substrates or coatings. Where necessary prepare test areas. Repairs to cracks, holes, blisters etc, should be carried out before application of the coating. Ensure roof surface is clean, dry and free from all loose debris and roof contaminants. All fungal growth, moss etc. should be treated with a suitable fungicidal cleaner. General dirt and contamination can be removed with Watco Bio D, a biodegradable solvent free degreaser.

Please note: Watco Liquid Roof Membrane is moisture activated, therefore once opened, all material must be used immediately. The tin cannot be re-sealed.


If appearance is critical we recommend the application of a small trial area first.

Do not apply if rain is forecast within 12 hours. Stir contents thoroughly (do not thin). Apply Watco Liquid Roof Membrane by brush or short/medium pile type roller. Work material well into substrate. Apply generous amounts to areas at a higher risk of water ingress i.e. joints and protrusions with a brush prior to the application of the main coating. Two coats are recommended. The second coat should be applied after a minimum of 8 hours and a maximum of 7 days. An anti slip finish can be achieved by sprinkling the coarse white grit over the second coat while it is still wet.

Data sheets

Data sheets

Safety data sheets

Safety Data Sheet

Technical data sheets

Technical Data Sheet
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£293.40 (Ex VAT)

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Tools and accessories

Paint Brush

Paint Brush

Professional paint brushes suitable for all coatings

From £2.50  (Ex VAT)

Watco Fibreglass Reinforcing Tape

Watco Fibreglass Reinforcing Tape

Strengthens and waterproofs joints and cracks in bund areas

£36.00  (Ex VAT)

12" Roller Frame & Handle

12" Roller Frame & Handle

A sturdy roller applying floor coatings

From £8.80  (Ex VAT)

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