Skylights & rooflights in Thornbury From the castle end of town to the newest estates

That is where an opening unit earns its keep. A roof window over the top flight of a long, narrow house gives warm air a way out right where it collects. Open it on a close evening and the stair starts to pull air through from the front door and the ground floor windows. In a back bedroom tucked under a rear slope, a roof window that tilts open gives the room its own supply of fresh air instead of whatever drifts along the landing.

The conservation area around the old centre

The historic core of Thornbury, from the High Street and Castle Street up to St Mary's church and Thornbury Castle, sits within a conservation area. South Gloucestershire Council looks after planning here, and some buildings in the centre are also listed. Any change to the roof of a listed building, a new rooflight included, needs listed building consent. In a conservation area the council may take a closer interest in how a front slope looks from the street, so a quick check with South Gloucestershire Council before you commit is time well spent. When permission is needed, and what to send with an application, is covered in our rooflight planning guide.

On the older roofs of the town centre, the usual answer is a conservation rooflight: a slim metal frame with a central glazing bar, made to sit low and flush in the slope so it reads like the iron rooflights that once lit attics and stores. Plenty of them open. A sash with a winding handle lets a cottage attic air properly while the roof keeps its period look.

Where the back range comes in

Some older houses in the centre have a lower range at the back: an old kitchen, a former workshop or an outbuilding joined on years ago. These often have a shallow or flat roof. A flat rooflight there brings daylight into a room that has lost its windows to a neighbour's wall, and an electric opening one lets cooking steam out without leaving the back door ajar. Sitting low behind the house, it is rarely seen from the street.

Old roofs need care, because the rafters in a house this old are rarely where a drawing would put them. We look at the roof from the loft side as well as the street, and say plainly if a smaller unit, or a pair, would suit the old timbers better than one large opening. Replacing a whole rooflight is notifiable building work, and the Building Regulations guide explains what that covers.

A town centre house can split the work between two slopes. The front slope, seen from the High Street, takes a single conservation unit, kept small and left fixed if the council prefers it that way. The rear slope, out of sight above the garden plot, takes a larger roof window that opens wide, with a vent bar along its top so a little air keeps moving overnight with the sash shut. The attic gets daylight from the front and air from the back.

Bungalows and chalet bungalows

Where a Thornbury bungalow has been extended up into the roof, the roof window does more than air the room. Upstairs in a Thornbury bungalow, or under the slopes of a chalet bungalow, the roof window can be the escape window for that room, which means its size and the height of its bottom edge both matter. We check this at the survey, and our page on roof windows as a fire escape explains the rules. A two-storey Thornbury semi with a converted loft is a different case: the rules ask for a protected stair, and the roof window is there to light and ventilate the room rather than to get anyone out.

The postwar terraces bring their own puzzle. A mid-terrace house has no side wall to open, so the landing and the bathroom depend on what sits above them. A roof window over the bathroom, set high enough to clear the shower, lets steam out at the top of the room, and a vent bar keeps a trickle of air moving when the sash is closed for the night. Where the bathroom sits under a flat-roofed section, a small opening flat rooflight does the same job.

Newer homes and the flat-roofed extension

On the newer estates the question is usually the extension. A rear kitchen with a flat roof and a large fixed rooflight looks good in the brochure and bakes on a July afternoon. Replacing that fixed unit with an opening flat rooflight, or adding a second one that opens, lets the heat out at the highest point of the room without opening the garden doors. If the extension has a lantern, a roof lantern can do the same job.

Height decides how a unit opens. A roof window in a loft bedroom within easy reach can be manual, tilted open from the handle by the bed. A flat rooflight three or more metres up in an extension needs to be electric or solar, with a rain sensor, so it actually gets opened. Solar suits a finished room where nobody wants new cable chased through the plaster.

Beyond the town itself we cover the villages round about, including Alveston and Olveston, as well as Yate. The costs page sets out what moves the price.