Skylights and rooflights for semis and bungalows in Kippax

Which way the window opens

Roof windows come in two opening styles. One swings about its middle, which suits a bed or desk placed beneath it. The other is hinged along the top and pushes outward, leaving full headroom at the sill, which counts if you walk under it daily. Where the furniture stands settles the choice.

As a way out of the room

A bedroom in a chalet bungalow's roof can rely on a roof window as its escape route, provided the sill sits within the height Approved Document B allows above the floor. That document sets minimum opening sizes, and we pick a model that meets them. A two-storey house with a new loft bedroom is a different matter, because that calls for a protected stair.

The fixed written quote gives the room, the model and the size of the unit, and because a new opening in the slope changes the roof's structure, we notify Building Control for that cut.

Fitting into a tiled slope

The tiles beside the opening come off and are kept, the battens are altered to suit the frame, and a flashing sized to the tile's profile goes in. The rafters are trimmed round the opening, and the frame sits on the timber. Tiles are then relaid to the flashing, so the slope looks continuous again.

Weather while the roof is open

Opening a slope takes a morning or a day, depending on the unit, and the hole is covered whenever work stops. A bungalow loft room is a small box, so the bed and floor below are sheeted before the first tile comes off and the dust stays in one place.

Plaster and paint under the roof

The ceiling finish in a roof room is usually plasterboard fixed straight to the rafters. We form a short light well between the roof and the room, line it, plaster the reveal and leave it ready to decorate. Insulation is packed round the frame so the opening does not turn into a cold spot in winter.

Rigid tube or flexible

Rigid tube gives a brighter result than a ribbed flexible one of the same length. The flexible type suits only a short offset round a timber, since each fold costs some brightness. The run on an estate house is often short, so a rigid tube with a single angled elbow can be enough.

Clearing the line through the loft

The line from dome to ceiling has to miss the water tank, the cold-water pipe, the extractor duct and the cables. The tube normally slots between neighbouring rafters. Cutting into a rafter or joist would make it structural work. We look from the hatch, trace the line and set the dome position on the slope to suit.

Roof pitch and dome

The dome is bedded in a flashing sized for the roof tile. On a low pitch the dome lies close to the surface; on a steeper one it stands slightly proud, and the tube is angled to meet it. The dome is clear acrylic, and sun and cloud both pass through it.

Fitting the diffuser

The ceiling end is the part you see, so it gets care. A hole is cut at the marked point, the tube is joined to a collar above it, and the diffuser clips into a trim ring that sits flat on the plasterboard. A bead of sealant on the ring closes it to the ceiling, and the joint is finished in paint.

What you notice in the bathroom

With the diffuser fitted, a bathroom that only had electric light has daylight in the morning. A cool white light fills the room and the tiles look the colour they were chosen to be. Some models include an electric light fitting in the tube, so the same opening lights the room after dark.

When the loft is not clear

If the bathroom has a bedroom or a store above it, the tube cannot run straight, and daylight from the roof may not be able to reach it. In a case like that we look at whether the landing or the stairwell could take a unit instead.

Reading the signs

• Condensation or a mineral film that sits between the panes, inside a unit whose edge seal has failed.
• A frame that is soft, split or stained at the lower edge, where water has sat.
• Cracked or crazed acrylic in an old domed rooflight, which no longer sheds water cleanly.
• A damp stain on the ceiling beside the opening after heavy rain.

New glazing in the old frame, or a new rooflight

If the frame is in good order and the opening is a common size, a new sealed glazed unit can sometimes be bedded into it. Where the frame is tired, or the rooflight is an old single-skin dome, we replace the entire rooflight and its upstand detail. The old unit comes out and a new one goes into the same opening, which leaves the roof alterations at a minimum.

The covering around the opening

On a flat roof the covering is carried up the outside of the kerb. If it has cracked, a new rooflight has little to seal against, so the upstand is renewed in the same visit and the roof work finishes in one go.

A better unit than the old one

The glass in a replacement can be better than what came out. Double or triple glazing, low-emissivity coatings and a thermally broken frame all reduce heat loss. A solar-control coating also helps a rooflight that faces a hot afternoon sun, so a converted garage does not overheat in July.

Permission for a like-for-like swap

Replacing a unit in the same opening disturbs much less of the roof than forming a new hole. For a house in the Leeds City Council area, the usual planning conditions apply to the new unit; the skylight planning guide sets them out, and a flat has its own rules.