What is a sliding sash window?
A sliding sash window (Dutch: schuifraam) is a window that opens by sliding rather than swinging or tilting. There are two main forms:
- Vertical sliding sash: one or both sashes slide up or down in rebates in the frame. This is the classic sash window of Dutch (and English) canal houses and townhouses, popular from the late seventeenth century onwards.
- Horizontal sliding window: the window slides sideways along a track, like a sliding patio door in miniature.
In the traditional vertical sash window, the weight of the sashes is balanced by counterweights. These hang from cords or chains that run over pulleys in the frame and move inside a hidden weight box in the side jambs. As a result, the window stays put at any height and is light to operate. In modern vertical sash windows, springs or balance mechanisms take over this role.
Application
Sash windows are found mainly in historic buildings, listed buildings and protected townscapes, but also in new-build in a classic style. A sash window does not blow open in the wind and takes up no space inside or outside, which is handy with narrow pavements or window sills.
Points to watch and tips:
- Draught-proofing: old sash windows are often draughty. Draught seals in the rebates and a brush or profile strip where the two sashes meet improve this considerably, without affecting the character.
- Cords and pulleys: replace frayed cords in good time; a window that suddenly drops is dangerous. Always secure the window while working on it.
- Do not paint it shut: paint in the rebates makes the window stiff. Keep running surfaces free of thick layers of paint and sand them lightly.
- Insulation: thin insulating glass or heritage glazing can often be fitted in an existing sash window. Check whether the sash timbers and the counterweights can handle the extra weight; the weights sometimes need to be made heavier.
- Listed building? In the Netherlands, replacing windows in a listed building or protected townscape often requires a permit, so check with the municipality beforehand. Other countries have their own rules; check with your local planning or heritage authority.
Related Terms
- Window frame
- Side-hung casement window
- Tilt-and-turn window
- Glazing bar
- Glazing bar layout of old windows
- Listed building
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