Aethos advice
Maintaining and painting timber sash windows
A sash window is a moving piece of joinery as well as part of the exterior envelope. Good decoration protects vulnerable timber without painting the mechanism shut.
By Aethos Studio · Published
Begin with operation and water paths
Open and close each sash before work. Inspect bottom rails, joints, glazing lines, cills, pulley stiles and the ends of exposed timber. Sticking, open joints, soft areas or water entering around the frame may require joinery or building repair before painting begins.
Distinguish coating failure from timber failure
Cracked paint can expose sound timber, but softness, persistent staining or loss of section changes the scope. Decoration cannot restore structural timber. A joiner should assess significant decay, failed cords, loose glazing or distorted components.
Remove what is unsound, not every historic layer by default
Loose paint needs removal and sound edges should be feathered. Wholesale stripping is a separate decision because it adds time, access and potential exposure to old coatings. Older paint may contain lead; if suspected, arrange appropriate testing and a safe method of working rather than dry sanding without controls.
Keep movement and drainage working
Thick layers of paint at meeting rails, channels and contact points can stop smooth operation. Drainage routes and weathering details must remain functional. The specification should separate decorated faces from unpainted moving or hardware surfaces.
Prime bare areas and respect the glazing line
Bare timber and repairs need a compatible primer and coating system. Junctions around glazing require careful preparation and a sound weathering detail. Product instructions decide coat build, drying and the conditions in which the window can safely be closed.
Inspect exposed windows more often
Coastal exposure is rarely equal on every elevation. Check faces exposed to the south and west, lower rails and cills regularly, and address local splits before broad failure develops. Keep a record of products and colours so maintenance remains compatible.
Plan exterior painting in St Andrews