Skylight and rooflight fitting in Stone, Kent

Travel shapes the place too. The A226 links Dartford with Greenhithe and Gravesend, the A2 and the M25 pass just north of the parish, and Stone Crossing station on London Road has served the village since 1908. Terraces and semis packed along a main road often have deep plans with a narrow frontage.

The back bedroom with the low eaves

Timber-framed and weatherboarded cottages tend to be low, with first-floor rooms that sit partly inside the roof. A back bedroom of that kind often has a window at knee height, if it has one at all. The deep part of the floor, beside the chimney breast or under the slope, stays dim even at midday. A roof window cut into the rear slope puts daylight on exactly that part of the room. It also lets you see the sky from the bed. The frame has to land between rafters, so the width of the bay between two timbers fixes the standard sizes that can go in without major alteration to the structure.

The utility room that came with the extension

Houses of the Victorian and later periods often have a single-storey addition on the back, a scullery turned into a utility room or a lean-to put up beside the kitchen. These rooms have one window at most, often looking onto a boundary fence or a neighbour's wall. When the room is also being used for laundry and storage, daylight from the roof makes the whole space easier to work in. A flat rooflight over the work surface is the usual answer for a flat extension roof, and a small sun tunnel works where the roof above is pitched and the loft sits close.

Near the river, the Darent Valley Path runs along the eastern edge of the village past old kilns. Houses facing open ground get a view but not always daylight in the rooms behind them, because the plan places the best windows at the front and back and leaves the centre to the stairs.

A garden room at the far end

Out at the end of the lawn, a garden room is a different sort of roof job. The walls may be mostly glass or timber cladding, and the roof is a flat deck or a shallow pitch. Glass doors light the near end of the room; a rooflight reaches the whole width, down to the back wall. The roof deck decides how the unit is fixed, so we look at the deck and its covering before choosing the frame.

Listed houses and the village centre

Stone Castle on London Road is listed at Grade II, and Littlebrook Manor House on Green Street Green Road is a listed farmhouse. Those are two of the older buildings in the parish. If your own house is on the list, a new or altered roof window will almost always need listed building consent, and the application goes through the council with drawings of the unit. The listed buildings guide sets out how that application is built. A rear slope and a low, slim-framed rooflight make the stronger case.

Inside a listed building, the council will want to know what the unit looks like from outside and what it replaces or disturbs inside. A conservation-style rooflight is made to sit close to the plane of the roof, and the drawing that goes with the application shows that. Putting the window on a slope hidden from the road, such as the rear of a cottage that backs onto the green or a garden, keeps the unit out of the street view.

Roof structure in older houses

The bigger building question in an older Stone house is usually the roof itself. In a timber-framed cottage the rafters may be irregular, the spacing uneven and the pegged joints original. A roof window needs a clear bay of the right width, with new trimmers fixed to the old frame, and we measure that bay from inside the loft before we price anything. Where a house has been extended, the old and new roofs can differ in pitch and covering, and each part is checked on its own before a position is chosen. In a Victorian terrace the roof is typically more regular, and the same measurements are quicker to take. Under a later roof built with factory-made trusses the web of timbers crosses the loft, which restricts where an opening can go and sometimes means the window moves a few hundred millimetres either way. Once the bay is fixed, we check the ceiling below it too, since the lining that carries daylight from the roof opening down into the room is cut to follow that same line, and a wide splay at the bottom spreads the light further across the floor.

Cutting into the roof brings Building Regulations into play. We handle the Building Control notification where the work is notifiable, and the Building Regulations guide lists what is checked: the structure around the opening, the energy rating of the glass and, in a loft room, the escape route.

Garden room

A garden room with a flat roof can take a flat rooflight or, if the room is large enough, a roof lantern. A lantern normally stands more than 150 mm above a flat roof, which usually puts it outside permitted development and brings in an application, as the roof lantern planning guide explains. Inside, a lantern gives the ceiling height and a pyramid of glass; outside, it adds to the roofline, so the neighbours' view comes into the decision. The structure of an outbuilding must carry the weight of the frame and glass, and that is something we check at the survey.

Some garden rooms are built with a pitched roof and a ridge that makes a roof window the better fit, and some have a green or felt-covered flat deck. We look at what is on top of the structure before we suggest a lantern or a rooflight, and the frame is secured to an upstand or kerb that is built for it, with flashings dressed over the edge.

Back bedroom

For the bedroom with the low eaves, a pitched-roof window is the product. A tall roof window at the top of a slope gives the best light across the room; a wider, shorter one lower down gives the view. Where the room is on a first floor with an escape window already in the wall, the new roof window is there for daylight, and the Building Regulations guide covers the other cases. The roof windows range lists the sizes. Blinds are worth specifying at the same time, because a south-facing slope can bring heat into a bedroom by mid-afternoon.

Utility room

A flat rooflight is the usual choice for a utility room on a flat extension roof, and a sun tunnel does the job under a pitched roof. The tube of a sun tunnel passes through the loft, so we check the run for pipes and cables first.

Nearby, Swanscombe and Ebbsfleet Valley are covered too.