Dormer windows: deep, tight and rarely straightforward

Where the blind mounts

Three options: inside the recess at the top of the reveal, face-fixed to the front of the recess, or fixed directly to the window frame. The choice depends on headroom above the sash and how the casement swings.

We measure headroom and the opening arc at survey, because a blind mounted 40mm too low will foul the window handle every time.

Products that suit a dormer

Small aperture, deep box — this narrows the field usefully.

• Roller with a slim cassette — takes minimal headroom
• Perfect-fit — fitted to the sash, no headroom needed at all
• Venetian — good for angling light in a low-ceilinged loft room
• Shutter with a scribed frame — where the cheeks are out of parallel

Cottage dormers

In older Kent cottages the dormer reveal is often plastered directly onto uneven masonry with no true right angles anywhere. A scribed shutter frame or a face-fit blind both cope; a recess-fit blind will show the unevenness.