Maintenance

To ensure cost-effective maintenance repainting should be carried out whilst the existing coating is still in good condition. In practice it is highly unlikely that different parts of a building will wear uniformly. However the objective should be to carry out maintenance procedures at those intervals which offer the greatest cost-effectiveness.

Identify the substrate and the existing paint system.
Examine the condition of the surface - note whether they are all in a poor condition or whether only parts of them are. Check how long since the property was painted and how the paint has performed during that period of time. Has it met expectations?
Check the horizontal members of windows - if they are in poor condition look at the glazing and note any points of water build-up. Assess if there are any major problems which cannot be cured by a new paint system. It may be for example that new glazing will be needed.
Remember moisture is taken in many times faster through the end grain than elsewhere so check that it is protected.
Exterior faults on joinery may be the result of interior glazing failures enabling moisture to penetrate from behind. If so interior glazing may need sealing.

Look for signs of condensation and if necessary consider extra ventilation. Wood is not only subject to attack from moisture outside the building but also from inside and behind.
Check the elevation. South and west elevations are subject to more weathering from sunlight and wind. North and east elevations are colder and tend to give rise to interior problems due to cold surfaces producing moisture from condensation.
Check the month as well as the year of the previous surface-coating application. It may be that the coating was applied in damp conditions when a lot of moisture could have been trapped in the wood.
Ask about any change of usage since the last application of a surface-coating system eg. an increase in internal condensation as a result of the installation of central heating or increased insulation which would make it more difficult for moisture to escape.
Check up on any changes in the surrounding area such as growth or removal of trees which would alter the environmental conditions.

Examine all internal joints between frames and walls.
Check these key design points: water traps open joints drips the way timber is set into the brickwork sharp arrises glazing beading rot and cracked putty.
Look at the interior glazing - it may be the cause of exterior problems. Ideally interior glazing should be sloped away from the glass.