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Buy Ronseal Knot Block Primer & Undercoat 250ml - White | JDSDIY.COM

Ronseal Knot Block Primer & Undercoat 250ml - White

Barcode: 5010214870356
Regular price
£8.34 GBP
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£8.34 GBP
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Completely stops wood knots and resins from showing through your paint. It also has 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
Wont yellow, crack, or peel

How to use knot block?

Before you start

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

Put down dust sheets to protect your floors from paint.


Use 120 grit sandpaper to lightly sand the wood. This will help you get an even finish and ensures the paint sticks.
If you have any loose, flaking, or peeling coatings, sand them off to reveal the bare wood.

Let the dust settle and wipe it up with white spirit and a cloth.
If you notice any cracks or holes, fill them in.

Give your tin a really thorough stir until it has a smooth consistency.
Use a brush and paint it in the direction of the grain.
Wait four hours for the first coat to dry.
Apply the second coat.
Wait four hours for it to dry and that is it, you have finished!

Aftercare Cleaning

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 easy to repair. Just sand down the area that needs repairing and then apply two more coats. And that it, it will be fixed.


We have a 14-day return policy, which means you have 14 days after receiving your item to request a return.

To be eligible for a return, your item must be in the same condition that you received it, unworn or unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase.

To start a return, you can contact us at If your return is accepted, we’ll send you a return shipping label, as well as instructions on how and where to send your package. Items sent back to us without first requesting a return will not be accepted.

You can always contact us for any return question at


All orders are processed within the same day. We will contact you if there are any delays. However, some orders may be despatched within the same day and some may take up to 1 day.

Standard Shipping

The order will arrive within 2-3 business days & will be tracked. Standard Shipping is FREE.

Express Shipping

The order will arrive within one business day. Express Shipping costs £1.99, ordering for the same dispatch has a cut off time of 3:00 pm every day except weekends. Express orders made after 3 pm will be dispatched the next day for next day delivery. 


0161 241 6842


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Unit S Highfield Road, Manchester, M38 9ST