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Watco 4 Hour Epoxy Primer

A fast drying primer for porous surfaces

  • Virtually solvent free
  • Reduces suction on porous floors
  • Binds weak and friable surfaces
  • Prevents bubbles forming in epoxy top coats

Frequently bought together


A two pack solvent free primer especially designed to reduce suction on porous, very absorbent surfaces prior to application of Watco Chemi Coat or Watco Resiflow. It has significant benefits over traditional water-based primers in respect of penetration, substrate binding and curing. Not for use on non-porous surfaces. 

Recommended areas of use

  • Priming bare, porous or open textured surfaces prior to applying a high build floor finish


  • Solvent free (not water based)
  • Binds weak and friable surface
  • Ensures maximum long term adhesion of the floor coating
  • Prime and coat in the same day cutting labour costs and waiting time
Properties Solvent-free, reduces suction on porous surfaces, helps to bind weak and friable surfaces, quick drying, reduces shut down time.
Suitable for Floors.
Interior or Exterior Interior.
Coverage Smooth concrete: 20m² per 5L. Acid etched concrete: 15m² per 5L. Shot blasted/open textured concrete: 12.5m² per 5L.
Number of coats 1
Curing time 2-4 hours at 10-15°C.
Minimum application temperature Air temperature: 15°C, floor temperature 10°C.
Pot life Up to 30 minutes at 15°C.

Surface preparation

Concrete and cementitious surfaces should be clean, dry and free of loose material. Watco Etch & Clean, an acidic preparatory agent, may be used to remove dirt (not grease) and loose cement deposits. Watco Bio D, a virtually solvent free virtually odourless degreaser, removes oil and grease. If the surface has to be wetted during preparation it should be left to dry as long as possible to allow the primer to penetrate. The primer will tolerate some dampness.


Pour the liquid contents of the two small tins (resin and hardener) into the larger outer tin and mix thoroughly until uniform in colour. The mixed components must be decanted into a scuttle and used immediately. If the mixed components are not decanted immediately, they will quickly become unusable and the mixing tin will become very hot and could pose a hazard.


Apply from the paint tray or scuttle using a medium pile simulated sheepskin roller working well into the surface. A brush may be used for cutting in. Apply in warm, well ventilated conditions.

Case studies

£62.00 (Ex VAT)

In stock

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Tools and accessories

Watco Etch & Clean

Watco Etch & Clean

Essential for preparing bare concrete ready for painting

£24.20  (Ex VAT)

Paint Brush

Paint Brush

Professional paint brushes suitable for all coatings

From £2.20  (Ex VAT)

Watco Paint Mixer

Watco Paint Mixer

A manual mixer for thorough mixing of two-part coatings

£3.00  (Ex VAT)

12" Roller Frame & Handle

12" Roller Frame & Handle

A sturdy roller applying floor coatings

From £7.70  (Ex VAT)

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Help & Advice

Contact our friendly and professional Technical Advisors for expert help and advice for your project. You can give us a call on 01483 418 418 or email

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