Painting and decorating


The painting and decorating of timber and timber-based materials shall be compatible with the species of timber, provide adequate protection and be suitable for the intended use and location. Prefabricated components and joinery shall be finished to a suitable quality, and protected.

When painting or decorating timber, the moisture content should be a maximum of 18%.

Paint and paint systems should be used in accordance with the manufacturer’s recommendations, and be compatible with the surface to be decorated.

Preparation should ensure:

  • door and window furniture is removed
  • unsound wood, loose or highly resinous knots, etc. are cut out, replaced and made good
  • raised grains, tool and machine marks are removed
  • surfaces are refinished with fillers and glasspaper as appropriate
  • nail holes, splits and other imperfections are stopped
  • sharp arrises are rubbed down (to enable an even coating)
  • surfaces are free from dirt, dust and moisture
  • where there is deterioration of the primer or seal coat, surfaces are rubbed down and a second coat applied
  • where joinery is delivered preprimed, priming meets the requirements in this chapter
  • where joinery is prefabricated, the first coat of paint or stain is applied before fixing.

Knotting should:

  • comply with BS 1336 ‘Specification for Knotting’ (this may not be effective against heavy exudation of resin)
  • be applied using a brush, or as part of the priming process for joinery.

One full round coat of primer should be applied to all surfaces to be painted, including:

  • hidden surfaces of external woodwork
  • cut ends of external woodwork
  • rebates for glazing and backs of glazing beads.

Primers should be in accordance with BS 7956 ‘Specification for primers for woodwork’.

Paint or stain should be applied to external timber to provide protection and stability, even where the timber has been preservative treated (unless the preservative treatment manufacturer confirms otherwise). Primer, paint and stain finishes should be compatible with preservative treatment.

Undercoat and gloss should be applied ensuring that it provides a satisfactory finish, and:

  • it is not thinned (unless recommended by the manufacturer)
  • each application is a full round coat and surfaces are lightly rubbed down with glasspaper between coats
  • a minimum of one priming coat, one undercoat and one finishing coat is used (unless an alternative recommendation is made by the manufacturer)
  • each coat is applied within one month of the previous.

Stain and varnishes should be:

  • applied as recommended by the manufacturer to provide appropriate cover
  • applied to surfaces which have been suitably prepared to provide adequate adhesion and an acceptable appearance
  • applied when the substrate is dry
  • suitable for the species of timber.

Varnish should be applied with a minimum of three coats on interior surfaces. On exterior surfaces, varnish should be suitable for the conditions (yacht or high gloss) and applied with a minimum of four coats. Surfaces should be sanded between coats.

Stain should:

  • be a two-coat system or be in accordance with the manufacturer’s recommendations
  • not be applied to door or window rebates which are to be glazed with linseed-oil putty.

BS EN 927-1 provides guidance on exterior wood coating systems.

Prefabricated joinery and components should be:

  • protected from damage
  • supplied with, or given, a coat of primer before fixing
  • stored under cover and primed, where supplied untreated, as soon as possible after delivery
  • reprimed where primer is damaged.