How to Seal Knotty Pine Walls Before Painting

How to Seal Knotty Pine Walls Before Painting. The wood knots in knotty pine walls have resin in them, which can seep from the wood and ruin a paint job. It's difficult to remove the resin from a surface, especially after it hardens. You can avoid such problems by properly preparing a knotty pine surface before painting it. This includes covering the knots with a primer that fills pores in the wood and prevents resin seepage.

Oil-based primers prevent pine resin from bleeding through paint.

Things Needed

  • Trisodium phosphate
  • Rubber gloves
  • Safety glasses
  • 3-gallon bucket
  • Sponge
  • 220-grit sandpaper
  • Rags
  • Oil-based primer
  • Paint pan
  • Nylon bristle paintbrush
  • Paint roller
  • Natural fiber roller cover (optional)
  • Satin or semigloss latex paint
  • Nylon roller cover

Step 1

Remove dirt and grime from a knotty pine wall with a degreaser, such as trisodium phosphate, commonly known as TSP. Wear rubber gloves and safety glasses when handling TSP. Dissolve a half-cup of TSP in 2 gallons of warm water in a 3-gallon bucket. Clean the wall with a sponge dampened with the TSP solution. Let the wall dry.

Step 2

Lightly sand the wall with 220-grit sandpaper if the surface is glossy. Don't overdo the sanding; just roughen the surface so that the primer will stick to it. Wipe the wall with a dry rag to remove any dust left behind from sanding.

Step 3

Pour the oil-based primer into a paint pan; make sure you have purchased one that prevents resins from bleeding through painted wood surfaces. Apply the primer to the wood knots with a nylon bristle paintbrush. Use a paint roller with a natural fiber cover to coat the entire wall if knots cover most of the surface.

Step 4

Allow several hours for the primer to dry completely. Test for dryness by ensuring that the surface doesn't feel sticky.

Step 5

Sand the areas you primed if they don't feel smooth after they dry. Remove dust from the sanded surfaces with a dry rag. Paint over the primer within a week to avoid a buildup of dust and dirt that interferes with the paint's adhesion.

Step 6

Apply one coat of satin or semigloss latex paint to the wall with a roller that has a nylon cover. Add a second coat after the first one dries if the first coat doesn't completely cover the primer.


  • Kilz and Zinsser brand oil-based primers help prevent resin seepage.
  • Natural fiber roller covers are made from mohair or lamb's wool blended with polyester.
  • A satin or semigloss latex paint creates a washable surface that's easy to clean.


  • Keep TSP powder and any TSP solution from coming into contact with your eyes and skin.
  • Follow the manufacturer's instructions for properly ventilating a room when using oil-based primers and interior paints.
  • Wear a mask when sanding to avoid inhaling the dust.


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