Putting skylights or rooflights up the slopes of Mold's Victorian terraces

Mold is where Flintshire County Council has its offices, and the town has the compact, hilly layout of an old market town. Around the High Street stands a core of older buildings, many with shops or offices below and rooms above. The River Alyn runs through the valley below, and the streets climb away from the centre on either side, so a house at the top of a terrace can look down onto the roofs of the one below.

Victorian terraces fill many of those slopes. They are brick houses with Welsh slate roofs, usually two storeys with an attic, and the narrow plots leave little room to the sides. Edwardian villas and larger detached houses sit on the better streets nearer the centre, with generous roofs and tall stairwells. These are the houses where a rooflight changes a dark landing, though they are also the houses most likely to be in the conservation area.

Beyond the terraces, the inter-war semis have hipped tiled roofs and central landings, and their lofts are often boarded out for storage or already made into a bedroom. After the war, local authority and private estates added plainer houses and bungalows, and in the last few decades newer estates have been added at the edges. The villages in the hills around the town, such as Gwernaffield and Gwernymynydd, have a similar mix on a smaller scale, and they fold into this page.

On a hillside street, the back roof is often the one you can reach, and the front roof is the one everybody sees.

That split guides most of the work. In a terrace, the roof windows for a loft room normally go in the rear slope, since the front slope faces the street and sometimes a protected outlook. Semis tend to use their rear roof too, and extension roofs at the back are flat or shallow, so the question there becomes which type of rooflight suits the roof.

Bungalows add another variation. They have a wide, low roof with a large loft space, and any room made in it needs a way out, which a roof window can supply because the opening is within the height allowed. A two-storey terrace or semi is another matter, because its loft conversion needs a protected stair and not an escape window in the roof.

Crossing into Flintshire means leaving the English rulebook behind. Flintshire County Council decides planning applications, and the permitted development rules it applies are the Welsh Government's own, not the English ones. Whether a rooflight needs an application depends on those rules, so check the permitted development pages on gov.wales and the council's own site at flintshire.gov.uk before you assume either way. A flat, or a house divided into flats, is treated differently from a single dwelling, and so is any property under a direction that takes permitted development away.

The town centre of Mold is a conservation area, and it contains buildings that are listed. Cadw, the Welsh Government's historic environment service, protects listed buildings in Wales, and a rooflight in one of them needs listed building consent. The Cadw website at cadw.gov.wales shows how listing works and how to find an entry. For a house in the conservation area, the best advice is to ask the council about the slope you have in mind before you order. Our conservation rooflight units are slim and sit down into the roof covering, which is the kind of product that finds most favour on a visible slope.

Before work starts, Flintshire County Council is given the Building Control notification by us, and how a Welsh rooflight is signed off is explained in the guide linked here.

The town centre conservation area is the part of Mold where the council is most likely to have a view, and the streets around the High Street, with their shopfronts, upper floors and slate roofs, are the ones to check first. A rear slope behind a parapet or a roof pitch that cannot be seen from the street is the easiest case, while a front slope facing the road needs a flush conservation unit and a conversation with the council. Further up the hill, the newer estates are rarely affected, and a rooflight there is a matter of the roof, the trusses and the weather.

The same sums apply to the villages in the surrounding hills, where an old farmhouse or barn conversion may be listed and will always need a look at its structure before a price is given. Many of these have deep stone walls, thick roof timbers and a roof void that is better than it first appears, so a rooflight can often be placed where the room needs it. We say at the survey what the council is likely to ask for.