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Concrete Floor Primer

Our cheapest two part epoxy floor primer

  • Strengthens and seals ready for painting
  • Great value - only £1.93 per litre
  • 5L covers approx, 30m²
  • Can be overcoated in 6-12 hours
  • Penetrates and binds weak, dusty concrete
  • Virtually odourless water-based formulation

Frequently bought together


Watco Basics Concrete Floor Primer 5L is a highly effective penetrative epoxy resin, which provides a sound, solid base when painting porous, dusty concrete. Being water based it can be applied to a damp substrate if the floor has been washed as part of the preparation, so speeding up the painting process. It is primarily designed for use under Watco Basics Epoxy Resin Floor Paint but is an ideal primer for use under any water based epoxy resin paint. Water based epoxy resin paints can be applied quickly to this primer. Other types of paint, solvent based or 100% solids epoxy can be used, but the primer should be left for at least 48 hours for all of the water to evaporate.

Recommended areas of use

  • Any bare, porous dusty concrete floor which needs sealing and dustproofing before painting.
Interior or Exterior Interior.
Composition Epoxy resin.
Number of components 2
Coverage 5L: 30m².
Recommended number of coats 1
Pot time (hours) 2
Drying time 4 hours.
Curing time 6 hours.
Minimum application temperature 10°C
Storage Do not allow to freeze.
Shelf life Shelf life is 24 months in unopened containers.

Surface preparation

Clean and prepare bare concrete using Watco Basics Acid Etcher.This will remove light grease and oil deposits. 
To remove heavier grease and oil use Watco Basics Floor Cleaner.This can also be used to remove grease from existing paint.
Make sure the surface is clean before continuing.
New concrete should be at least 2 months old. 
This primer is water-based, so it doesn’t matter if the floor is slightly damp after cleaning.


Holes in excess of 5mm deep can be filled with Watco Basics Floor Repair Mortar, or providing the floor is level, Watco Pourable Repair Mortar
For repairs which need to be ‘feather edged’ to nothing, or for repairs to damaged joint edges, please refer to Watco Concrex epoxy resin repair mortar. This should also be used if repairing broken kerb edges or step nosings.


Check the air temperature is around a minimum of 15°C and the floor temperature at least 10°C.
Stir the contents of the resin and curing agent tins individually, and then empty the contents of the resin into the curing agent tin.
Mix the two components thoroughly using a wide bladed tool such as a piece of batten. A paint mixer in an electric drill is ideal.   
Tip the contents into a paint tray and apply using a medium pile roller. A brush can be used to cut in around edges. 
Now it is mixed you have up to 2 hours to apply it before it become unusable. 
Do not apply thickly, but work it into the concrete surface using the roller.

Important: The performance of water-based paint is affected by poor ventilation, damp and low temperatures. The drying times quoted above will extend in any of these conditions.


Do not apply if the floor temperature is below 10°C.
Not recommended (and not necessary for) smooth, dense, non-porous or painted surfaces - instead see Watco Powerfloat Primer.
Do not use in confined spaces with little or no ventilation since it won’t dry. Watco 4 Hour Epoxy Primer is suitable for these conditions.

£57.80 (Ex VAT)

In stock

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Tools and accessories

Acid Etcher

Acid Etcher

Cheap floor preparation essential for painting

£21.00  (Ex VAT)

Floor Cleaner

Floor Cleaner

Budget-friendly dirt and grease remover

From £21.00  (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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