Rooflights and skylights in Comberton

Close to the church and the green, the oldest houses tend to sit under fairly steep pitches in clay tile or slate, and here and there a roof may still carry thatch. A steep, plain tile or slate covering is the easiest surface to fit a slim roof window into: the flashing lies flat against it, and the frame sits low and discreet in the plane of the roof. Where a roof does turn out to be thatched, a rooflight through it is a specialist job in its own right with its own fire and ventilation detailing, so we look at that kind of roof on its individual merits rather than offering a standard answer.

The bungalows that make up so much of the village were mostly built with a fairly shallow, hipped roof and a section of steeper tile pitch carrying the dormer cheeks that light the rooms inside. Concrete interlocking tiles are the usual covering, and the trusses inside are often a simple cut roof rather than the engineered trussed rafters you find in newer estates, which gives a bit more room to work around when placing a new opening. The newest homes at the edge of the village, by contrast, almost always use factory made trussed rafters, and a truss cannot simply be cut to make way for a wider unit without an engineer's input first.

• Clay tile or slate on the old core: a slim roof window sits low and quiet in the roof plane.
• Thatch on the oldest cottages: treated as a specialist job with its own detailing, never assumed.
• Bungalow hip and dormer cheeks: cut roof construction, more flexibility for a new opening.
• Trussed rafters on newer plots: any wider unit needs a structural check before we cut anything.

For most houses that are not listed and not caught by any additional restriction, a rooflight on an existing roof counts as permitted development. The national limits apply regardless of where in the village the house stands: the unit cannot project more than 150mm beyond the plane of the roof slope, it cannot sit higher than the highest part of the existing roof, and any window in a side facing slope needs obscured glazing and must be fixed shut unless its opening part sits at least 1.7 metres above the floor. Flats and maisonettes do not carry these rights at all, so any rooflight on a converted flat needs a full application regardless of size.

The older part of the village, nearer the church and the green, may lie within a conservation area, and we never assume either way for a given house. We check the Greater Cambridge Shared Planning constraints map before we quote on any Comberton address, and a lawful development certificate is available where an owner wants written confirmation that no application is needed. Being inside a conservation area does not remove permitted development for rooflights on its own, though an Article 4 direction can, and a listed building always needs listed building consent for any new opening. Where a house does sit in a sensitive spot, a flush fitting conservation rooflight, set into the roof covering rather than sitting proud of it, is the usual answer. Our guide to planning permission for rooflights covers the wider rules in more depth.

A roof window from an older dormer can usually be swapped for a current model built to the same size, keeping the existing lining and plaster intact and avoiding disturbance to the cheek around it. Where the exact size is no longer made, an adapter flashing or a close equivalent unit closes the gap. A flat rooflight on an old kerb is a bigger undertaking, because the timber kerb itself is often too low by today's standard, poorly insulated, or soft where water has sat against it over the years, in which case we rebuild the kerb to the right height before the new unit goes on. Our page on misted and failed rooflight replacement sets out how that swap is planned in more detail.

A replacement is also a natural point to rethink the light rather than simply match what was there. A south facing dormer window that has always made the bedroom under it stuffy in summer is a good candidate for solar control glass or a blind at the same time as the unit is renewed. A dim north facing skylight, on the other hand, is often a candidate for a larger opening once the old kerb or frame comes out. Our guide to which way a skylight should face covers this reasoning for every orientation.

Do I need planning permission for a rooflight in Comberton?

Often not. On a house that is not listed and has no Article 4 direction affecting it, a rooflight on an existing roof is usually permitted development within the standard 150mm projection limit. Flats, maisonettes and listed buildings do not have that right and always need an application. We check the Greater Cambridge Shared Planning constraints map for your address before we quote.

Can you fit a rooflight into a 1960s or 1970s chalet bungalow?

Yes, and it is one of the most common jobs we do in Comberton. A roof window set into the rear slope beside the existing dormer, or a sun tunnel for a windowless landing or bathroom, both work well with the simple cut roof construction found in most bungalows of this age.

Is the older part of the village near the church treated differently?

It can be, if the house is listed or the address falls within a conservation area, so we never assume either way. We check the constraints map for the specific property first, and where a house is sensitive we usually recommend a flush fitting conservation rooflight sized in proportion to the roof.