Exterior painting

Doors and windows

Instructions - Exterior windows

Choice of product

  • Always choose a tinted product, as colourless oil, semi-transparent wood finishes, or lacquer do not provide adequate UV protection.
  • Oil treatment deepens the natural colour of wood.
  • Treat doors and windows with oil once or twice a year.
  • Always use oil on surfaces previously treated with oil.
  • Apply either Valtti Puuöljy Akva (Wood Oil Akva) or Valtti Puuöljy (Wood Oil) to surfaces treated with Valtti Wood Oil Akva, and likewise for Valtti Puuöljy. 
  • Apply either water-borne Valtti Akvacolor or solvent-borne Valtti Color to surfaces treated with water-borne Valtti Akvacolor semi-transparent wood stain, and likewise for Valtti Color. 

Before treatment

  • The surface must be dry before treatment. The air, surface to be treated, and the product temperature must all be at least +5 °C.  Relative humidity must be below 80%; or below 70% when applying Unica Super Lacquer semi-matt.
  • Wood moisture content must be under 20%.
  • Always read the instructions on the product label before use.
  • The best weather for painting is when it is warm and overcast. Do not paint when there is evening dew, when rain is expected, or in direct sunlight.
  • Wash off mould with a solution of Tikkurila Homeenpoisto (Mould Removal), 1 part to 3 parts water. Brush the mould removal solution upwards. Let the solution take effect and rinse down with plenty of water starting from the top downwards. After washing, the surfaces will require maintenance treatment.
  • Choose the undercoat and topcoat of the same colour.
  • Remove or mask door fittings and handles before painting. If you paint when the door is in place, secure it with a wedge.
  • Plan suitable painting order, for example, paint window frames from the top downwards.
  • When treating wood surfaces with semi-transparent finishes, the final colour of the wood depends on its species, hardness, and original colour, and the number of times it has been treated. Make a small test application first to ensure the final colour!
  • For an even finish, always apply semi-transparent finishes in continuous strokes parallel to the grain.
  • Let new, impregnated wood weather for at least half a year before surface treatment.


During treatment

  • Stir products thoroughly both before and during application.
  • To prevent moisture from entering the wood through the ends and joints, apply both undercoat and topcoats to them thoroughly.
  • If you continue painting the following day, put the paint roller in a plastic bag and seal tightly  overnight.

After treatment

  • Let the paint dry properly. For paints and lacquers, surface dry is not sufficient. Depending on the product and coat thickness, final drying may take anything from one to four weeks.
  • Check the condition of surface treatment once a year and carry out any necessary maintenance treatment in good time! Surfaces facing south and west suffer the effects of the sun more severely and may require maintenance treatment much more frequently than other surfaces. Painted surfaces often require less frequent maintenance treatment than surfaces treated with semi-transparent wood finishes or wood oil.

  • If there is any paint or lacquer left over, put the lid carefully back on the can to form a tight fit. Turn the can upside down for a moment to make the lid airtight. Opened and/or tinted products cannot withstand prolonged storage.

  • Take liquid paint waste to a hazardous waste collection point. Empty or dry cans can be taken to a recycling point or to a public waste disposal site.