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Visible wood knots and resinous bleeding through paint

Problem - Visible wood knots and resinous bleeding through paint
Wood knots are visible as dark spots on light paint and light spots on dark paint.
Bleeding: Yellowish droplets form on paint surfaces, especially on south-facing walls.

Possible causes

  • Wood knots have not been treated with Tikkurila Oksalakka (Knotting Lacquer).
  • Incorrect priming.
  • Use of very knotty wood.
  • Use of very resinous wood.
  • Temperature and humidity variation causes resinous agents (resin) to migrate to the paint surface.


Resinous agents are present in all wood types. The migration of resinous agents can be prevented by treating the surface with a combination of primers designed to resist moisture.

Repaint the surface if there are several visible knots. Scrape off the resin.
Clean the surface with Tikkurila Homeenpoisto (Mould Removal) according to instructions on the label, rinse thoroughly and allow to dry (see Mould). Treat the knots with Oksalakka (Knotting Lacquer). Apply primer undercoat to the clean wooden surfaces. Paint with a suitable Tikkurila exterior paint according to instructions.