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Knot Block Wood Primer and Undercoat


Completely stops wood knots and resins from showing through your paint. It’s also a primer and undercoat which means you can tackle two jobs at the same time. It covers bold colours and dark marks to give you a flawless finish.

  • Everything you need in one tin
  • Guaranteed to block wood knots
  • Ready to paint over in four hours
  • Can be used on bare or previously painted wood
  • Won’t yellow, crack or peel
  • Non yellowing formula
  • Guaranteed to block out wood knots
  • Used onto Bare or painted wood
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Coverage Calculator

How much Primer and Undercoat do I need?

Measure your area precisely, drop the numbers into this smart calculator and it will tell you straight away how many litres you'll need to complete your project.

Use for the following wood types
  • Interior wood
    Interior wood
  • Doors & windows
    Doors & windows
  • Smooth planed wood
    Smooth planed wood

1 colours available including:


How to use knot block

Before you start

This primer preps your for painting but you still need to prep for the primer.

Put down dust sheets to protect your floors from paint.


  1. Use 120 grit sandpaper to lightly sand the wood. This will help you get an even finish and ensures the paint sticks.
  2. If you have any loose, flaking or peeling coatings sand them off to reveal the bare wood.
  3. Let the dust settle and wipe it up with white spirit and a cloth.
  4. If you notice any cracks or holes, fill them in.


  1. Give your tin a really thorough stir until it’s a smooth consistency.
  2. Use a brush and paint it on in the direction of the grain.
  3. Wait four hours for the first coat to dry.
  4. Apply the second coat.
  5. Wait four hours for it to dry and that’s it, you’ve finished!



Your brushes can easily be cleaned in warm soapy water.

Remember this is only a primer and undercoat, so you should paint over it.


If you notice damage or your primer has chipped, it’s easy to repair. Just sand down the area that needs repairing and then apply two more coats. And that’s it, it’ll be fixed.

Technical specification

Usage Interior wood including windows, doors and skirting boards
Coverage Up to 12m2 per litre
Dry time Four hours
Coat time Four hours
Number of coats Two
Colours White
Finish Matt
Durability Stops knots in their tracks
Application Brush
Sizes 0.25L, 0.75L, 2.5L

How to guides

Easy to follow steps to help you do a professional job on any DIY project.
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HOW-TO How to choose the right primer for the job
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