Which rooflight and skylight suits the grey-slate pit terraces of Haydock

Haydock grew because of coal. Collieries drew workers to the area in the nineteenth century, and the terraces built for them are the earliest housing in the town: plain brick rows, two rooms up and two down, a yard behind and a slate roof running front to back in one clean slope. Some have a rear outshut with a lean-to roof, a feature that matters when light has to travel from the kitchen up to the bedroom above it.

The mines closed and the land changed use. Industrial units spread along the east side of the town near the junction of the A580 and the M6 corridor, and housing filled much of the rest. The interwar period brought council semis and short terraces to estates off Clipsley Lane and towards Blackbrook, with hipped roofs in tile, generous front gardens and rooms laid out around a central hall. A loft conversion or a rear kitchen extension is the usual way of finding more room.

After the war more estates followed, often with plain gabled roofs and concrete tiles, then the newer developments on ground cleared of old industry. These later houses are quick to build and uniform: brick or render, gabled roofs, trussed rafters and a kitchen-diner at the back. Their roofs are easy to survey but the trusses limit how wide an opening can be, because a roof window can usually sit between two trusses and nowhere else.

Beyond the housing, Haydock Park Racecourse and the surrounding open land give the area a green edge, and the farm buildings and older cottages that survive along the lanes are a different case again. They are few, usually have thick stone or brick walls with a roof structure of heavy timbers, and each needs looking at individually.

Many pit-village terraces also keep a rear scullery or outshut whose roof runs on from the main slope at a shallower angle. That lower slope sits over the room downstairs that gets the least light, the kitchen, and a small flat rooflight or a short sun tunnel through the outshut can change it without touching the bedroom above. Where neighbours have extended along the same row, the party wall upstand and the flashing against it are checked first, since the shared junction is where water finds its way in. A survey from the loft and the yard shows which of these a given house has.

The checks that follow come from these roofs, not from a template, and they decide what size and type of unit is practical on a given house.

• Whether the terrace roof has a rear outshut that changes the slope
• If the rafters on a 1930s roof are the original timbers or have been strengthened
• The spacing of trusses in a newer estate house
• Where the loft hatch and any boarding sit relative to the opening
• Whether a loft already has a gable window that limits furniture placement

Planning for Haydock is dealt with by St Helens Borough Council. Where a Haydock house still has its permitted development rights, a pitched-roof rooflight can go in without an application, as long as it meets the conditions for a rooflight on a pitched roof. We go through those with you at the survey and confirm them against the roof in front of us.

Most of Haydock is ordinary housing that does not carry special controls, but there are exceptions worth checking. An upstairs flat in a converted house cannot rely on permitted development, since flats and maisonettes are left out of it, so an application comes first. Listed buildings come next: a farmhouse on the edge of town, an old chapel or a converted pub would each need listed building consent before a rooflight is cut. Some streets or estates may also sit under an Article 4 direction, which is how a council withdraws the rights locally. St Helens' planning team can say whether any of that touches your address, and we will wait for its reply before going further. If you want to check the position before we call, the planning pages on sthelens.gov.uk are the place to start. For a slope that faces the road, what planners look at on a front-facing roof window goes through the points.

Building Control is where the routine work lands, and St Helens Borough Council is the body we notify for you; what the regulations expect of the new unit has a page to itself.

For a house with a loft conversion in hand there is a further layer. A bedroom in the roof brings fire-safety and stair rules with it, and the means-of-escape answer sets out when a roof window may act as the exit. The paperwork and the work usually run in this order.

1. Check the address. Listed, flat or Article 4 area? That decides whether an application comes first.
2. Survey. We measure the roof and settle the unit and the fitting.
3. Notify Building Control. The notice goes in before the first slate is lifted.
4. Fitting. The unit goes in, the roof is made good and the interior is cleaned.
5. Certificate. The signed-off paperwork arrives and is filed with the deeds.