Flat rooflights.

A flat rooflight reads as a flat plane of sky. The frame is minimal — visible only at the perimeter — and the geometry sits flush against the roof line so the roof itself stays uninterrupted in elevation. Where a roof lantern would announce itself with pitched glazing bars, a flat rooflight quietly disappears.

Maxlight flat rooflights are made to bespoke dimensions up to 3.0 × 3.0 m per panel. The frame is thermally broken aluminium with the same finish range as our wall systems, so a project specifying both can match the metalwork tone exactly. Glass is double or triple-glazed laminated, sealed with a clamped extrusion at the perimeter and drained via a concealed perimeter channel.

Pitch matters more than it sounds. 0° (truly flat) is buildable and looks clean from below, but loses some self-cleaning rinse from rainfall — for a 0° unit we specify a self-cleaning glass coating as standard. 1–3° is the sweet spot: visually flat from inside, sufficient fall for drainage. Above 5° the rooflight starts to read as pitched, which is a different aesthetic and often the wrong one for a contemporary extension.

For a kitchen extension, a flat rooflight over the dining island is one of the most reliable design moves on the UK market. Daylight from above changes the room far more than equivalent wall windows; the flat geometry stays subordinate to the architectural moment. We specify these constantly and it is rare to be wrong.

When a flat rooflight makes sense. The architectural reading wants the rooflight to disappear into the ceiling plane rather than read as an overhead form; the structural opening is rectilinear and does not call for a pitched lantern; the U-value brief sits at Approved Document L 2025 limits or below; the project does not need walk-on capability over the rooflight. The Maxlight flat rooflight is the canonical recommendation for these projects.

When something else makes sense. Pitched roof lanterns suit traditional or transitional architectural register; walk-on rooflights are the right specification when foot traffic over the glass is part of the brief (terraces, courtyards, basement light-wells); structural laminated rooflights cover bespoke load conditions outside the standard product envelope.

Detail considerations. The flat rooflight kerb is engineered against the project roof build-up: insulation thickness, weatherproofing membrane, lead or single-ply flashing, and the timber or metal upstand the rooflight clamps to. The detail carries water away from the rooflight perimeter via a 1:80 minimum fall on the outer kerb and a continuous EPDM seal at the glass edge. coordinated at design stage so the kerb height matches the finished build-up.

Regulatory context. Whole-rooflight U-value is rated against BS EN 14351-1 and BFRC-tested; the rated figure (not the centre-pane number) is what Building Control assesses against Approved Document L 2025. Air permeability and water tightness sit in the standard sliding-system suite (Class 4 / Class E1200). Class 1 safety glass per Approved Document N applies wherever the rooflight sits at a height that calls for it.