Roof lanterns in London, geometry that lifts the room.
Glazing London supplies and installs slim aluminium roof lanterns across London, made to size for kitchen extensions, flat-roof additions and orangery-style rooms. Part L compliant glazing, thermally broken frames, and a free survey and quote. Call 07399 253464, any hour, 24/7.
Hipped lantern on an insulated kerb · drawn to type, made to your sizes
Why extensions get lanterns, not just rooflights.
A flat rooflight lets light fall straight down. A lantern does that and adds volume: the pitched glass lifts the ceiling line, so a 2.5m-high extension feels taller in the middle, and light enters at an angle through the morning and evening rather than only at midday. On a typical London kitchen extension the lantern sits over the island or the table, where people actually gather. If you want glass in the roof without the raised profile, a flat unit from our rooflights and skylights range is the quieter choice, and we fit both, so the advice is on merit.
What a lantern job includes
- Survey and sizing against your roof plan or the finished kerb
- Thermally broken aluminium frame, powder-coated, made to order
- Low-E argon-filled glass units, toughened outer and laminated inner
- Installation, flashing and weathering by our own fitters
- Part L compliance and building control sign-off where an opening is cut
Aluminium roof lantern sizes
Every lantern is made to order, so these are starting points rather than a fixed catalogue. Ridge height rises with width: a 1500mm-wide lantern adds roughly 350 to 450mm at the ridge, a 2000mm-wide lantern around 500 to 600mm, worth knowing for permitted development height limits.
Rule of thumb: keep 400 to 500mm of flat roof between the lantern kerb and any edge or parapet so falls and flashings work properly. Two smaller lanterns often light a long room more evenly than one giant, and cost less to lift onto the roof.
What holds the geometry up
Frame Thermally broken aluminium
Slim powder-coated aluminium with a polyamide thermal break, so the inside face stays warm and condensation-free. Anthracite grey (RAL 7016) outside with white inside is the London favourite, and any RAL colour is available. Aluminium spans wider than uPVC with less bulk, the same reason our aluminium windows and doors carry the biggest panes.
Glass Part L and beyond
Low-E coated, argon-filled units around 1.0 to 1.2 W/m²K, with a toughened outer pane and laminated inner pane so overhead glass fails safe. Solar control tints cut summer gain on south-facing roofs, and self-cleaning coatings earn their keep on glass you cannot reach with a squeegee.
Kerb The part nobody photographs
The lantern is only as good as the insulated upstand it sits on. We build or check the kerb, typically 150mm above the finished roof, square, level and insulated, before the frame is fixed and weathered. Most lantern leaks trace back to a bad kerb, not bad glass, which is why we treat it as part of the job.
Sign-off Building control, handled
Cutting a lantern opening into an existing flat roof means trimming joists, structural work that needs building control approval, and we arrange the inspection and paperwork. On a new extension the lantern simply joins your builder's existing application. Either way you end up with the certificate in hand.
Replacing the roof of a conservatory rather than a flat roof? That is its own trade, covered on our conservatory roof replacement page. And if a pane cracks at any point, our 24/7 emergency glazing team will make it safe the same day.