Rooflights and skylights in Waterbeach

The older village grew up around its church and main street, on slightly higher ground at the edge of the fen, in the way most Cambridgeshire villages did: close together, long plots running back from the road, and rooms that were built long before anyone thought about daylight from above. To the south and west, the land that was RAF Waterbeach and later the army's Waterbeach Barracks is now being developed as a new town, in phases that will run for years yet. A short walk can take you from a cottage with walls two feet thick to a street of houses that did not exist a decade ago.

Both kinds of house benefit from a rooflight, but for different reasons. An old cottage usually needs light reached into a room that has none. A new house is already well lit at the front and back, and the question there is more often about heat, glare and which roof structure will actually accept an opening. Rather than start from a catalogue, we start from the room and the roof in front of us, using the same light planning method we apply across Cambridge and the surrounding villages, and we adjust it to whichever of Waterbeach's two stories your house belongs to.

Roofs of this age are commonly built on trussed rafters rather than the older cut roof of a cottage. The timbers are lighter, spaced fairly close together, and each truss is doing a designed job, so a wide roof window cannot simply be cut in without checking what it displaces. A unit sized to sit between two trusses is usually the simplest route; wider openings get an engineer's trimming design, and those calculations travel to Building Control with the notification.

Rear extensions on these houses tend to be single storey, flat roofed, and used as a kitchen or dining space, which is exactly where a flat rooflight or a small lantern earns its keep. A flat roof rooflight stands on an upstand that lets rain run clear, and it can be positioned directly over a worktop or table rather than lighting the ceiling and leaving the surface below it in shade. Where the extension runs the width of the back of the house, a roof lantern draws in sky from more than one direction and carries light further into an open plan room than a flat pane of the same size.

• a roof window sized between trusses for a bedroom or landing
• a flat rooflight on a raised kerb over a kitchen or dining extension
• a sun tunnel for a bathroom or hallway with a loft void above but no nearby slope

A south-facing slope with open sky above it takes several hours of direct sun through the middle of the day for much of the year. In December that sun is low and welcome, reaching deep into a room; in June and July the same slope takes high, strong sun for hours, and without the right glass a room under it can overheat. A north-facing slope gives steady, even light with almost no glare, which suits a home office, a study or a landing where you want light without a hot spot. East and west slopes bring low, angled sun at breakfast and in the evening, pleasant to sit in but capable of dazzling a screen or a worktop if nothing controls it.

Wind and driven rain matter here too. An open aspect towards the fen edge gives a roof little to break the weather, so flashing details for the actual pitch and covering matter more than they would on a sheltered slope in the middle of a Cambridge terrace. On the glass itself, a south or west slope usually calls for solar control glazing with a lower g-value, sometimes paired with a blind, while a north slope is better served by keeping heat in through the winter than by keeping it out in summer. Our skylight orientation guide sets out what each aspect gives a room, and the glass options are explained on our energy efficient rooflights page.

Fogging between the panes of a rooflight points to a failed edge seal that has let moisture into the unit; daylight through it turns dull, the sky disappears, and it now insulates far worse than a current unit would. Older polycarbonate domes on flat-roofed extensions can turn brittle and discoloured after enough summers, and an early roof window can be draughty and stiff to operate. In each case the sensible answer is a new, properly fitted unit rather than trying to nurse the old one along.

Replacement is also worth using as a moment to check position, not only glass. An opening set over the middle of a kitchen floor might do more good moved above the worktop, or it might be well placed already and simply need solar control glass because the slope faces south and the room runs warm in summer. Sometimes changing the glass and frame in the existing opening is the whole job. Our misted and failed rooflight replacement page explains what is involved, and a like-for-like swap on a pitched roof can often be finished in a day, where a new kerb on a flat roof takes a little longer.

Do I need planning permission for a rooflight in Waterbeach?

Often not. Most rooflights on a house are permitted development if they project no more than 150mm from the roof slope and stay below the ridge. A listed building always needs listed building consent, and where a house sits within the village's historic core we check the current position on the Greater Cambridge planning map rather than assume it.

My house is on one of the new streets. Can a planning condition stop me adding a skylight?

It can, on some phases. Because the new town is being developed in stages, the planning permission for a particular phase sometimes removes permitted development rights for later roof alterations. We check the decision notice for your phase, alongside any title covenant or warranty term, before designing the opening.

Can an old rooflight from a 1960s or 1970s extension be replaced with something better?

Yes. A misted or worn unit from that era is usually holding the room back on both light and heat loss. Replacing it to current Building Regulations, and reconsidering its glass or position at the same time, is often the simplest way to improve a room that has been living with a dated rooflight for years.