Guide
Original sash windows: decorating them as joinery
A sash window that sticks, rattles or will not stay up has a joinery problem, and no amount of paint is the answer to it.
What a sash actually is
A box sash is a mechanism: two sliding sashes hung on cords over pulleys, counterbalanced by weights inside the boxes at each side, running against parting beads and held in by staff beads. Glass is bedded in putty. Every one of those parts wears.
Decorating a sash therefore means deciding what is a paint item and what is not. Cords, beads, pulleys, putty and easing are repairs; they are surveyed and priced as such rather than absorbed into a decorating rate and then skipped.
Paint build, and why windows stick
The most common cause of a sash that will not move is decades of paint bridging the gap between the sash and the bead. Painting over it again makes it worse. The work is to cut the seal, remove enough build to restore clearance, and ease the sash so it runs before it is finished.
That is also why a properly decorated sash takes longer than the wall it sits in. Preparation is the job; the finish coats are the short part at the end.
Putty, glass and the parts that fail quietly
Failed putty lets water sit against the timber in the bottom rail, which is where sash windows rot first. Localised putty replacement and repair to a sound rail is ordinary work. A bottom rail that has gone soft through is a joinery repair, and we will say so rather than filling it and painting over.
Cords are consumable. If one has broken, the others are the same age, and replacing all of them while the sash is out is cheaper than doing it four times over four years.
Conservation, listing and colour
Original windows are frequently the feature an Article 4 direction exists to protect, and on a listed building they are usually part of what is listed. That governs replacement rather than redecoration, but it also means external colour can be controlled, particularly on a terrace that reads as a single composition.
Working around occupied rooms
Sash work means an open window for part of a day and a room that cannot be fully closed up while a sash is out. In an occupied house that is sequenced room by room, weather permitting, so the property is never comprehensively open.
Where windows are in scope alongside internal decoration, windows go first: they are the messiest and the most weather-dependent part of the programme.
Questions
Usually. The seal is cut carefully and paint build removed from the running surfaces, then the sash is eased until it moves properly. Where a sash has been screwed or nailed shut — common where a cord broke years ago — that is repaired rather than forced. Occasionally a sash has been overpainted so heavily that stripping is the only honest route, and we would say so before starting.
External joinery is on a different cycle from internal decoration, so yes, quite often. Windows weather and want attention sooner; interiors are usually driven by how the rooms look. Where both are in scope they are sequenced together, but there is no reason to defer window maintenance until an interior needs doing.
The work this applies to
Where this comes up
Related guides
- Decorating period plaster: lime, patches and lining paper
A wall in a converted Victorian house is usually three or four different materials wearing the same colour.
- Renovating in a conservation area: what consent actually covers
Much of North West London sits in a conservation area, and the rules bite far harder on the outside of a building than on the rooms inside it.