Rooflights and skylights in Great Bookham, between the commons and the Downs

Bookham is a spring-line settlement. The North Downs rise to the south-east, and the village is surrounded by commons and woodland. Houses gather where the water once came out of the hill, and that old pattern still decides how the place feels today.

The 2011 census recorded 11,375 people across the Bookham North and South wards, which cover Great and Little Bookham together. That is a large village by any measure. Its civil parish was abolished on 1 April 1974, and Mole Valley District Council has handled its planning matters since then. The two Bookhams share a station, a shopping street and a good deal of tree cover.

Trees matter to a rooflight more than people expect. Woodland at the edge of a garden can shade a south-facing roof in the afternoon, drop leaves and needles onto flat glass, and change the quality of the light that reaches a loft room. When we plan a skylight here we look at what stands around the house before we decide where to cut. A bright opening facing a dense oak is not the same as the same opening facing open sky.

Mole Valley produced a Great Bookham Conservation Area Appraisal and Management Plan in 2011, and a separate one for Little Bookham the same year. These documents are the council's own description of what it wants to protect, and they are the first place we send an owner who lives near the old centre.

The district has 26 conservation areas in total, so the planning team deals with this question regularly and publishes its guidance openly. The council's conservation areas pages list them and explain what designation means.

Whether your own roof falls inside the boundary is something we check for the address, never guess from the street name. Two houses on the same road can be on either side of a line. If the house is inside, a roof slope that faces a public road is the part most likely to need care, and a rear slope usually raises fewer concerns. The first step is a planning question before it is a building one.

The A246 is the direct road between Leatherhead and Guildford, and it runs through Great Bookham. Road noise travels upward as well as sideways, and a loft room on the road side of the house can hear it through thin glass, worn seals or a poorly fixed frame. Bookham station on Church Road adds the sound of trains to the list, and a rooflight facing the railway takes that sound with it.

We do not quote noise figures. We describe quiet by specification, which is what a homeowner can actually check on the paper. The table below sets out how each source is usually handled.

Because Bookham is ringed by commons and woodland, tree cover is part of the design of a rooflight. A few points come up at a survey.

A roof that faces a stand of mature trees may get broken light, strong in winter when the leaves are off and dim in summer when they are on. That argues for a slightly larger opening, so the room has enough light at the dullest time. A roof that is shaded for part of the day can often do well with a unit that opens, since the room may run cool and damp more easily than one in full sun.

Leaf litter on flat glass is a matter for the kerb and the fall. A rooflight set on a kerb of the right height sheds water and debris better than one set too low. The roof around it needs a fall that carries water away, and a fall of 1:80 is the least we would look for on a flat roof. A lower fall leaves water standing, which ages the membrane and the seals.

The questions below are the ones a homeowner in this part of Mole Valley tends to raise first.