Rooflight and skylight installation in Chipping Campden, and the covering it has to suit.

Burgage plots, back ranges, and the slope that faces nobody

The reason a Campden job is workable at all is the shape of the plots. The medieval burgage layout gave each frontage a long narrow strip running back from the street, and over four centuries those strips filled with rear ranges, wings, outshots, workshops and coach houses. A house with fifteen metres of frontage may have forty metres of building behind it.

That back land is where the daylight comes from. A rear range roof, set down behind the main ridge, enclosed by garden walls and the backs of the neighbouring plots, is frequently invisible from any public place. It is also frequently the roof over the kitchen, the utility or the back stair, which are the darkest spaces in the house. Establishing which slopes are genuinely unseen, including from any higher ground, is the first survey task in Campden and it is done with a camera on a pole rather than by assumption.

Dover’s Hill above the town, and roofs that are looked down on

The complication is topography. Campden sits below the escarpment, and there is high ground north west of the town from which the whole roofscape is read as one surface. Long views into a settlement are a material consideration, and the officers here use them.

Practically that means the hidden rear slope test is stricter in Campden than it is in a flat town. A slope screened at street level can still be fully visible from a footpath four hundred metres away and eighty metres up. Photographs taken from those high points, showing the proposed position marked, are worth including with an application rather than waiting to be asked for them.

What a Campden stone slate roof weighs, and how that decides the frame

Cotswold stone slate here runs commonly 20 to 30mm thick, and a slated slope loads the structure at well over 100 kilograms per square metre before any snow. A standard manufactured roof window and its flashing kit are designed around a covering a fraction of that depth. Set one into a Campden roof and the frame stands proud, the kit cannot bed down onto an irregular 25mm slate, and the result reads as a modern object bolted to an old building.

A conservation unit exists for exactly this. Slim cast or pressed steel frame, a single central glazing bar, a low profile designed to sit nearly flush in a thick slate, and a dark matt factory finish. On a Campden application the officer will very often name the type in the condition rather than leave it to the applicant. Sizes, finishes and the fixing detail are on conservation rooflight installation, and the full treatment of the covering itself is on rooflights in natural slate roofs.

Torching under a Campden roof, and the detail agreed in advance

Under a good proportion of these roofs there is no underlay at all. The joints between the slates are sealed from below with a lime mortar torching, often mixed with animal hair, applied to the underside of the slates between riven battens. It is historic fabric in its own right and it cannot be taken off and put back as it was.

So the replacement detail is agreed with the conservation officer before the scaffold goes up, not decided on the boards on the second morning. The usual answer around a new opening is a breather membrane on counter battens, kept local to the work, with the surviving torching left undisturbed beyond it. Written into a method statement and submitted with the application, that detail turns a contentious point into a settled one.

Lead formed on site, because a moulded kit will not bed on Campden stone

Every manufactured flashing kit is pressed to a profile: flat for slate, troughed for pantile, deep for a profiled concrete tile. None of them is pressed for an irregular hand split stone slate 25mm thick with a different exposure on every course.

On a Campden roof the weathering is formed in lead on the scaffold. Code 4 for the apron and side pieces, code 5 where the piece is exposed or acts as a gutter, dressed with a bossing stick to the actual slates it is sitting on, lapped at least 150mm and fixed at the head only so it can move along its length. Lead nailed down both edges tears itself apart within a few winters, and cracked lead along an old fixing line is one of the commonest findings when a previous opening in this town is taken apart. The metal itself is covered on lead flashing and weathering detail.

Two small units instead of one, and why that lands better in Campden

A recurring pattern across approvals in this district is that two modest openings are accepted where one large one is refused. There are three reasons and they all apply here.

• Total glazed area on a single slope is frequently capped by condition, and two small units can come in under a cap that one large one breaks.
• A small unit stays within one rafter bay and one comfortable run of coursing, so the structural work and the disturbance to historic fabric are both smaller.
• Two openings spread across a room light it more evenly than one in the middle, so the daylight outcome is usually better as well as the consent outcome.

The pairing is set out symmetrically about a feature on the elevation below, or aligned with the openings that are already there, because alignment with the existing rhythm is the condition that comes back most often on a Campden approval.

Scaffold on a High Street plot, and a town full of visitors

Access in Campden is a real cost line rather than a footnote. Many plots have no vehicular route to the rear at all, so scaffold is carried through the house or down a narrow passage between buildings by hand. Where a licence is needed to stand a tower or a lorry on the public highway the district and the county highway authority both have a say, and that takes lead time.

The town also carries a steady flow of visitors on foot through the working day, and the Cotswold Way starts from the Market Hall, so the footway cannot simply be closed for convenience. Deliveries get timed early, the working area is kept tight and fenced, and stone is stacked on the scaffold rather than on the pavement. All of it is looked at during the survey so the figure that follows holds.

How a Campden enquiry turns into a fixed price

Send photographs of the roof from every direction it can be seen from, including any long view from higher ground, a photograph of the room inside, a note of the covering if you know it, and the address. An indicative range comes back by email within a day or two, together with the designation position for that address, which in this town is usually the piece of information that shapes everything else.

A survey follows, taking measurements of the coursing, the gauge, the slate thickness, the rafter positions and the pitch, plus the access route and where material can be landed. The fixed price is itemised after that: unit, labour, scaffold, reclaimed stone, lead, Building Control, and any pre-application work. The workmanship carries a ten year guarantee. Coverage across the north Cotswolds and the rest of the county is on the areas pages, neighbouring wolds towns including Moreton-in-Marsh and Stow-on-the-Wold have their own, and the costs page explains how a range becomes a figure that holds.