The Best Knotting Solutions For Sealing Knots

Prevent wood knots from discolouring your paint with our handpicked selection of knotting solutions.
Tried & Tested: See Our Testing ↓
Written & Tested By: Edward Bailey | Updated:
Best Knotting Solution
Edward Bailey/DIY Works
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Before painting any wood, it’s important that you treat any knots with a knotting solution to avoid any seepage or discolouration of the final finish.

Although you could skip this step and go straight to painting, after a few years you may begin to see the consequences as the seepage from the knots begins to discolour the paint.

To help you choose a suitable knotting solution, our hand-picked selection features top-performing formulas chosen through our first-hand experience treating knots (as shown in the image above), testing and the latest research.

Rustins White Knotting Solution
Best Overall: Rustins White Knotting
Ronseal Colron Knotting Solution
Best All-Rounder: Ronseal Colron Knotting Solution
Ronseal Knot Block Primer and Undercoat
Best Primer: Ronseal Knot Block
Liberon Knotting Pale
Best Value: Liberon Knotting Pale
Centurion Patent Knotting Sealer
Best Value Runner-Up: Centurion Patent Knotting Sealer

How The DIY Works Team Tests & Rates Knotting Solutions

Whilst changing all the door frames, architraves and skirting boards within a recent house renovation, we took the chance to test a number of knotting solutions.

This involved brushing the formula onto the knots before painting. We also tested the solutions upon an outdoor wooden seating area and so far it’s certainly stopped any seepages from the knots.

Although many people skip this step, we highly advise you don’t because after a year or two, you’ll soon see the seepage from the knots in the wood discolour your paint.

Knotting Solution

Edward Bailey/DIY Works

As well as testing, we also based our recommendations upon plenty of research and a number of factors. The factors that we considered included their effectiveness, ease of application, compatibility, time to dry and value.

The Best Knotting Solutions

At DIY Works, our content is 100% independent and we would never recommend a product that we wouldn't use ourselves (read our editorial standards and how we test products).

1. Best Overall: Rustins White Knotting

(How We Review →)

By far the most popular and highly rated knotting solution is by the Rustins brand. It’s designed specifically to seal knots in wood and other timber and it can also be used for interior or exterior use.

  • Pure shellac formulation
  • Large 300 ml bottle
  • Easy to apply by brush
  • Suitable for interior and exterior use
  • During our testing, we found that it required two coats

Overall, the Rustins knotting solution ticks all the boxes and it does exactly what it sets out to do on the bottle, which is of course to seal knots. It isn’t the cheapest formula but it’s definitely worth paying the extra for. We used this particular formula before painting skirting boards and we have no complaints whatsoever.

2. Best All-Rounder: Ronseal Colron Knotting Solution

(How We Review →)

The Ronseal Colron is another popular knotting solution that permanently seals knots and resinous timber. A unique feature of this particular knotting solution is the fact that it comes with an in pack brush. This has the benefit of less mess and no requirement of a paint brush when treating knots with this solution.

  • Supplied with a brush for application
  • Low odour formula
  • Easy to apply and fast drying
  • Prevents discolouration
  • Most expensive per 100 ml
  • Only suitable for interior use

The Colron knotting solution by Ronseal is a great option to consider that’s highly effective and even comes with its own brush. However, unlike the Rustins alternative, it’s only suitable for interior use and also comes in a much smaller bottle, which means it may be expensive to use if you are treating lots of knots.

3. Best Primer: Ronseal Knot Block

(How We Review →)

Another formula by the Ronseal brand is their Knot Block, which is a wood primer and undercoat solution. According to the brand, it’s everything that you need in a tin and it’s guaranteed to block wood knots.

  • Primer and undercoat formulation
  • Permanently seals wood knots and resins
  • Won’t yellow, crack or peel
  • Touch dry in 30 minutes
  • Helps paint stick and last longer
  • Relatively expensive when compared to the alternatives

To conclude, the Ronseal Knot Block is by far the best knotting solution if you want a base ready to paint onto such as skirting, door frames and architraves. The only drawback is the premium price tag but when you consider that it primes and undercoats, it’s a worthwhile investment that you won’t regret.

4. Best Value: Liberon Knotting Pale

(How We Review →)

One of the cheapest knotting solutions on the market that’s actually worth buying is the Liberon Knotting Pale. According to the brand, it’s suitable for all types of wood and it can be painted upon after two hours.

  • Touch dry in 15 minutes
  • Highly effective at preventing seepages from knots
  • Pale in colour
  • Suitable for use with clear varnishes
  • During testing, we found that it output quite a strong odour during the application

Overall, the Liberon Knotting Pale is an excellent all-round option that’s effective and offers great value for the money. Regardless of the type of wood that you treat, you can rest assure that this formula won’t allow any seepage.

5. Best Value Runner-Up: Centurion Patent Knotting Sealer

(How We Review →)

The Centurion Knotting Sealer is another relatively affordable solution that comes in a large 500 ml tin for treating plenty of wood knots. It’s designed to be used prior to priming and undercoating and it can be easily brushed onto the wood with ease.

  • Prevents discolouration
  • Fast drying formulation
  • Brush application
  • Interior or exterior use
  • Requires multiple coats for the best results

Overall, the Centurion Knotting Sealer is a great option to consider that’s affordable, effective and won’t disappoint.


Although you can go ahead and paint onto wooden surfaces straightaway, you may regret it later on. Wood knots can ruin the completed finish of the top coat and cause discolouration. Therefore, to avoid disappointed, it’s crucial that you treat the wood knots before applying a primer or undercoat. All of our recommendations above are suitable for all types of wood and are very easy to apply.

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