Best Windows for a Bay Front

Original Edwardian and 1930s bays had specific proportions: deep bottom rails, slim glazing bars, six-over-two or eight-over-two sash arrangements, and mullions between panels that were substantial enough to read as structure. Replacement bays that lose these proportions age the house immediately.

Edwardian bays (pre-1918): timber sash reproductions or high-end uPVC flush casement with heritage bar overlays. 1930s bays: uPVC or timber casement with authentic proportions and dark colour finishes (heritage green, Cotswold cream). Post-war bays: less constrained — modern uPVC casements work fine.

Original bay windows are load-bearing — the return walls and central mullion support the tile-hung or rendered bay roof above. Replacement must maintain this. A survey should confirm that the replacement frame can carry the same load; some heavy tile-hung bays need a steel or timber transom above the window as part of the replacement.

Often ignored, always dating. Original bay roofs used lead, clay tile or fibre-cement slates. A GRP replacement roof looks acceptable but a flat felted bay roof reads cheap. Where the original tile-hung roof is intact, keep it and just replace the windows within it.

A three-panel uPVC bay in heritage colour: £3,500–£5,500. Timber sash bay reproduction: £8,000–£15,000+. Timber-aluminium bay (like Rationel or Velfac): £6,000–£10,000. All prices assume replacement within the existing structural opening, fitted with FENSA certification.