Masseys DIY Store

Ronseal Knot Block Wood Primer and Undercoat

RRP £8.99£27.99


Ronseal Knot Block Wood Primer and Undercoat

Ronseal 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


Use for the following wood types

  • Interior wood

    Interior wood

  • Doors & windows

    Doors & windows

  • Smooth planed wood

    Smooth planed wood



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.

Weight 1 kg

250ml Paint, 750ml Paint, 2.5L Paint

Ronseal Knot BlockRonseal Knot Block Wood Primer and Undercoat
RRP £8.99£27.99Select options