Doors, windows and glazing

Also see:
3.3
9.5

6.7.4Timber doors and windows

Timber and wood-based materials shall be of suitable quality and be naturally durable or suitably treated. Issues to be taken into account include:

  1. classification and use
  2. drying shrinkage
  3. preparation and finish.

Classification and use

Timber windows should:

  • comply with BS 644
  • have a minimum 15mm rebate where double glazed units are to be installed.

Timber and wood-based materials should comply with the relevant requirements of BS EN 942 as follows:

Glazing beadsEuropean Redwood
Casements and sash windowsJ classes
All other elementsTable 1 of BS EN 942

In England, Wales, Northern Ireland and the Isle of Man, planted stops are not permitted on frames to external doors.

External doors should be 42.5mm minimum (44mm nominal) in thickness.

Drying shrinkage

To minimise drying shrinkage, the moisture content of joinery, when fixed, should not exceed the value given in Table 2.

Table 2: Moisture content of joinery

Preparation and finish

The following elements of timber doors and windows should be of naturally durable timber or timber pretreated against fungal decay:

  • External door frames.
  • Windows.
  • Timber surrounds to metal windows.
  • External doors, other than flush doors.

Where material is:

  • to be painted, it should be primed before fixing
  • to be stained, it should have the first coat applied before delivery to site.

Compatibility between preservative treatment or primer, with glazing compounds, sealants and finishes, should be checked with the relevant manufacturers.

Prefabricated items should comply with the relevant parts of BS 1186 : Part 2, including:

  • the fit and construction of joints and moving parts
  • the construction of finger joints
  • gluing and laminating
  • surface finishes.