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Knot Block Wood Primer and Undercoat

Knot Block Wood Primer & Undercoat 750ml DIGITAL.png

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
  • Permanently blocks wood knots
  • Helps paint stick & last longer
  • Touch dry in 30 minutes

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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 colour available including:


Need to know

Touch dry in only 30 minutes and ready to paint over in four hours. Watch our video to find out how to use knot block.

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Quick tip

You can paint over this primer with any colour you like and the knots won’t ruin your finish.

Number of coats

2 coats to completely stop knots



Coat time

4 hours

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 250ml - This tin will cover 1.5m2 with 2 coats
750ml - This tin covers 4.5m2 with 2 coats
2.5L - This tin will cover 14m2 with 2 coats
Dry time Touch dry in 30 minutes, paint over in 4 hours
Coat time Four hours
Number of coats Two
Colours White
Finish Matt
Durability Stops knots in their tracks
Application Brush
Sizes 250ml, 750ml, 2.5L
VOC Medium

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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HOW-TO How to choose the right indoor wood paint
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