Rooflight and skylight installation in Prettygate

Vaulting a ceiling

The most transformative thing that can be done to a bungalow room, and rooflights are what make it work.

Removing a flat ceiling and following the line of the rafters turns a low room into a tall one. It needs structural attention, because the ceiling joists in a traditional cut roof are usually acting as ties holding the feet of the rafters together, and simply cutting them out lets the roof spread. The answer is a ridge beam or collar arrangement designed by an engineer, and it is routine work.

Once the ceiling is open, the rooflights do something they cannot do in a flat ceilinged room: they sit in the pitched plane at high level and throw light across the whole space rather than down into one pool. A pair of roof windows in a vaulted bungalow living room changes the character of the house.

Where the roof is trussed rather than cut, vaulting means replacing the structure and it is a much larger project. Check the loft before planning anything.

Chalet bungalows and loft rooms

A good number of Prettygate bungalows have rooms in the roof already, or the head height to gain them. The measurement that decides it is from the top of the existing ceiling joists to the underside of the ridge, and you want comfortably over 2.4 metres before a floor, insulation and plasterboard eat into it.

Where a loft room is created, the roof window is usually doing two jobs: daylight and means of escape. The escape duty brings a minimum openable area and a maximum sill height, and it rules out some designs. A top hung window that swings clear generally satisfies it where a centre pivot does not, because the sash sits in the opening. Settle that at design stage rather than at order stage.

Coverings and pitch

Mostly concrete interlocking tiles on pitches around 30 to 35 degrees, which is straightforward but demands the correct deep profile flashing kit rather than the flat kit used on slate. A flat kit on a profiled tile leaves voids under the tile that water finds within a season, and it is the most common fault we find on other people’s work.

Some of the earlier properties have clay tiles or, occasionally, slate. Those are gentler to work with but more fragile, and an allowance for broken tiles is sensible on anything over fifty years old.

Flat roof work

Rear extensions on these plots are common and flat roof skylights over them are steady work. The detail we check first is the kerb: a 150mm upstand with the deck falling away from it, insulated on its outer face. A rooflight bedded onto a flat deck sits in whatever water the roof holds, and every flat roof holds some.

Permissions

Prettygate is outside any conservation designation and the housing is not listed, so permitted development normally applies. A rooflight is permitted provided it projects no more than 150mm beyond the plane of the roof and does not sit above the highest part of it, with extra restrictions on side elevations facing a boundary.

Vaulting a ceiling or converting a loft is a different matter and is notifiable under Building Regulations regardless of whether planning permission is needed. We handle Building Control where the work requires it.

Getting the specification right

Rigid, not flexible. A rigid mirrored tube reflects 98 percent or better at each bounce. A flexible foil concertina reflects perhaps 80 percent and scatters light at every fold, and the difference compounds along the run. On the short runs available here a rigid tube is easy to route, so there is rarely a reason to accept the cheaper product.

Diameter is the decision that matters. Output goes with area rather than width, so a 350mm tube passes roughly twice the light of a 250mm one rather than forty percent more. As a guide: 250mm for an internal WC or a small ensuite, 350mm for a landing, a decent bathroom or a small kitchen, 530mm for a room you actually live in.

Two beat one. Two smaller tunnels spaced apart read as ambient daylight. One larger tunnel reads as a spotlight in the middle of the ceiling. In a bungalow hallway, two is usually the better answer.

Insulate the tube where it crosses the loft. A metal tube through unheated space collects condensation, and water running down it arrives at the diffuser looking exactly like a leak. Seal the ceiling ring airtight as well, so room air cannot get into the tube in the first place.

What it will and will not do

It is not a rooflight. There is no view, no ventilation and no sense of sky, and after dusk there is nothing. Most units take an optional light fitting inside the diffuser so the same ceiling opening does both jobs.

What it is, on a dull afternoon in a windowless bathroom, is enough soft daylight not to reach for the switch. For the money, that is a good proposition and it is why we recommend it over a rooflight in a fair number of Prettygate jobs where a rooflight would have cost three times as much.

Maintenance

Less than anything else we fit. Clean the roof dome when the gutters are done, because the whole product depends on collecting light and a dirty dome costs output directly. Check the flashing every few years after a storm. Twist off the ceiling diffuser occasionally and wipe its upper face.

What eventually fails is the dome. Polycarbonate yellows under ultraviolet over fifteen to twenty years and is a replaceable part. A glass dome costs more initially and does not degrade. The mirrored tube itself has nothing to wear out.

What it costs here

Less than almost anywhere in Colchester, for two reasons that both come from the bungalow.

The run is short, so there is less tube and fewer bends. And the access is easy, because single storey eaves are reachable from a tower on almost every plot here and the gardens have room to stand one. Access is the line that most often surprises people on a rooflight quotation, and on a Prettygate bungalow it barely registers.

Send a photograph of the roof and one of the ceiling where you want the light, and say roughly what is in the loft between the two. That is enough for a realistic price without a visit.