Planning a rooflight or skylight for the mill and pit terraces of Coppull

Coppull has the look of a village that was built quickly for a purpose. When coal drew workers in during the nineteenth century, and two large cotton mills followed in the early twentieth, rows of brick terraces went up near the pits and the mills, tight to the pavement, two rooms down and two up, with slate roofs at a shallow pitch. Many have a rear outshut or a yard kitchen, and quite a few have been extended further. Those streets are the oldest and most uniform part of the village, and they set the template for what a Coppull roof is: low, plain and sturdy.

The railway line that links Wigan and Preston runs beside the village, and the stretches nearest the line and the old industrial sites are where the older terraces cluster. Beyond them the village loosened out. Inter-war and post-war semis arrived with larger plots, bay windows and pitched roofs in clay or concrete tile. Bungalows came next on the quieter lanes, and recent estates have taken up fields on the edges, with detached houses that have steep roofs and tall gables.

For rooflights, the era governs three things. The first is the rafter, because Victorian roofs often use light timbers at closer centres than a modern truss. The second is the covering, which runs from slate on the terraces to concrete tile on later work. The third is the headroom, since a 1960s bungalow has a shallow pitch and a small loft, while a new-build detached house has a deep roof void that takes a wide window easily.

Rear extensions on the terraces vary from one house to the next: some are brick outshuts under a mono-pitch slate or felt roof, others are later flat-roofed kitchens, so neighbouring houses on one street can need two different rooflights. Chimney stacks on the party walls limit where an opening can go, and the surveyor marks positions from inside the loft against the stack and the wall, and nothing is marked on the roof until that is done.

Coppull is in Lancashire, within the borough of Chorley, and Chorley Council is the local planning authority. Its website, chorley.gov.uk, is the place to look at planning policy and any designations that apply to your street. Since a guess would help nobody, no conservation area is named here for Coppull. If your address is inside a protected area, the surveyor finds out when the survey is booked and says so before the quote is written.

For almost every house in the village, the planning position is simple. Without an application, most houses can take a rooflight; the permitted development conditions list the limits, so they are not repeated here. Those rights do not reach flats and maisonettes, and an Article 4 direction on a street can take them away from a house. A rooflight on the front slope of a terrace raises its own points, which roof windows on the front of a house sets out. A listed building needs consent before any work starts, which how that application is handled explains; inside a protected area, what councils usually accept is the useful read.

Coppull has no shortage of extended terraces, and extensions are where the paperwork most often goes astray. A rear kitchen added years ago may have been built without a certificate, and a new rooflight over it is controlled work in its own right. The survey asks what is already on record, so that the new certificate covers the rooflight cleanly and does not trip over earlier history.

Fitting a rooflight in Coppull is notifiable work, so Chorley Council's building control is told by us before work starts; the route through Building Control, step by step covers the rest.

Energy limits sit in Approved Document L 2021, volume 1. Table 4.2 sets the limits for an existing dwelling: 1.4 W/m²K or Window Energy Rating band B for a roof window, with 2.2 W/m²K for a rooflight, a category that includes the roof lantern. What is promised in writing once the installation is done is on the guarantee page.