Above the worktop the roof is either pitched or flat, and each is handled its own way. A pitched slope receives a roof window set between rafters, finished with a flashing kit that laps into tiles or slates. A flat roof receives its rooflight on a kerb, a raised timber upstand finished in waterproofing and set to the fall.
On a pitched roof, the work is on the tiles and the loft. The covering is lifted around the opening, rafters are trimmed and a framed opening is made for the window. Flashings tuck beneath the covering higher up and sit over the covering lower down. A quick check of the angle and the covering decides which kit applies.
On a flat roof, the deck, the waterproofing and the structure under them need to be sound. We look for a worn covering, ponding and a deck that moves. A covering near the end of its life is best renewed round the kerb in the same visit, so the new work sits in good roof.
In both cases the aim is a weathertight junction that lasts. The edges decide how long a rooflight stays dry, so the frame detail matters above all else up there.
Access shapes the day on site. A rear roof behind a terrace may be reached through a side passage or over a neighbouring roof, and the materials have to be lifted in. We plan the lift, scaffold or access tower at survey stage and note it in the quote, so nothing is added later.