Flat Glass Rooflight in a Kingston Extension

A homeowner in Kingston asked us to add extra natural light to a newly built rear extension. The answer was a long, narrow flat glass rooflight set into the strip of flat roof running alongside the neighbouring wall, carrying daylight into the part of the room furthest from the garden doors.

Forming the opening

The extension was already structurally complete, with painted steel beams spanning the room and the ceiling boarded out. We formed the rooflight aperture in the strip of roof between the steels, trimming it in timber so the kerb would sit square and true. At this stage the opening was still open to the sky, looking straight out onto the scaffold and the neighbouring brickwork.

Rooflight opening formed in the extension ceiling between red painted steel beams, open to the sky — The aperture formed between the painted steels, still open to the sky.

View from inside the extension up through the open rooflight aperture to the scaffolding above — Looking up through the opening to the scaffold, with the garden doors below.

Setting the glass

The glass unit was lifted into position from the scaffold and bedded onto the kerb, then sealed and dressed in. Because the rooflight sits in a tight gap between the new extension roof and the older wall alongside it, the perimeter detailing mattered as much as the glass itself. Getting the upstand and the roof covering to meet cleanly is what keeps the junction watertight.

Newly installed flat glass rooflight seen from roof level, sitting in the narrow gap beside the neighbouring brick wall — The glass in place, seen from roof level in the narrow gap beside the neighbouring wall.

Flat glass rooflight installed on the extension roof, viewed along its length from the scaffold — Viewed along its length from the scaffold, with the roof covering dressed up to the kerb.

The finished result inside

From inside, the rooflight reads as a clean slot of sky in the ceiling. The reveals were boarded and taped ready for plaster, and the light now reaches right back over the kitchen rather than stopping a metre or two inside the garden doors. On a bright day the room needs no artificial light at all.

Glazed rooflight seen from inside the extension with the kitchen below and daylight filling the room — Daylight reaching back over the kitchen from the glazed rooflight.

Finished flat glass rooflight in the extension ceiling with blue sky above and garden doors below — The finished rooflight, with sky overhead and the garden doors at the far end.

If your extension feels darker in the middle than it should, a rooflight is usually the simplest fix. We install flat glass skylights and roof lanterns across London and Surrey, and you can see more of our recent work on our installations page.

Talk to us about a rooflight for your extension

Frequently asked questions

Why fit a long, narrow rooflight rather than a square one?

A long rooflight that runs back towards the original house pulls daylight into the deepest part of the plan, which is usually the darkest. On this Kingston extension the glass sits in the narrow strip of flat roof beside the neighbouring wall, so it lights the middle of the room without competing with the garden doors at the far end.

Can a rooflight be fitted between structural steels?

Yes. The opening is designed alongside the steelwork so the kerb sits neatly between the beams. On this project the painted steels were already in place, and the aperture was formed and trimmed in timber between them before the glass unit was set on top.

Do flat glass rooflights need a kerb?

Almost always. A flat glass rooflight sits on an upstand, or kerb, built above the roof deck. The kerb lifts the glass clear of standing water and gives the roof covering something to dress up against, which is what keeps the detail watertight over the long term.