Matching a rooflight or skylight to thick-walled cottages by the River Alyn at Hope

Hope is a village with a long history, and its oldest buildings are in stone. Around the parish church and along the lanes that run towards the river you find cottages and small farmhouses built of local stone, with thick walls, deep window reveals and roofs of slate. Some, with chimney stacks built into the gable wall and window openings of different ages, have been altered and extended over the centuries until the roof is a patchwork of slopes, with a lower outshut at the back and an older ridge above.

The Alyn valley was a working place, sharing in Flintshire's industrial century, and brick and stone terraces went up in the nineteenth century for working families. These houses are narrow and plain, with a pitched slate roof, a small back yard and often a single-storey kitchen added behind. Their upper rooms tend to be small and their landings dark, with a steep, narrow stair rising from a back room that often has no window of its own.

The twentieth century came next. Inter-war semis with hipped tile roofs appeared on the edges of the village, followed by post-war bungalows and chalet-style homes on larger plots, especially on the roads towards Caergwrle and up towards the hill. Newer estates fill the remaining ground, with concrete-tiled roofs, small gables and shallow lofts that were sold as storage rather than rooms.

Some of the most interesting roofs are on the farms and barns around the village. A converted barn has rafters and purlins sized for hay and not for double glazing, and the roof has no ceiling to hide the timber. A rooflight there is as much about the architecture as the light.

All of these houses are in a Welsh village, where visitors and incomers come for the hills and the walking, and a number of homes have been extended to make room for lofts and sun rooms. The loft is the room most often added, and in a cottage it is often the only place where a bedroom can be made at all.

Cottages put a particular question to a rooflight: how much can the old structure bear? A roof that has carried slate for a century or more may have settled, and the ridge is rarely perfectly straight. We look at the line of the roof from the garden before we go inside, then confirm the position from the loft side, so the new frame sits square to the rafters and the lining reveals look right in the room.

Many Hope homes also face views of the hills, and people like a window that opens to them. A roof window above a stair or in a bedroom can do that, if it is set at a height where you can see out from the room.

Hope is in Wales, and that changes the rules. Flintshire County Council is the planning authority, and the permitted development order that applies was made by the Welsh Government, so English limits never enter a quote for a Hope house. The current Welsh rules are at gov.wales, and how that right works in broad terms is covered in the planning guide. Different rules cover flats and maisonettes, listed buildings and homes under a local direction, and Flintshire County Council at flintshire.gov.uk can confirm which applies to yours.

Age brings extra care. Listed building consent is needed for any rooflight on a listed building in Wales, and Cadw, the Welsh Government's historic environment service, handles those buildings. Cadw explains how at cadw.gov.wales. We cannot say which individual Hope buildings are listed, and we do not guess; the council will tell you. A roof in a protected area is usually expected to take a slim, flush unit, and what a conservation area asks of a rooflight is set out separately.

Under the Welsh regime we tell Flintshire County Council's building control about the work, and how a Welsh rooflight is judged against Approved Document L (Wales) is covered in a guide.

A loft bedroom in a bungalow or chalet raises the question of escape from the room, and when a roof window counts as the way out depends on its size and height.