Sherburn in Elmet skylights and rooflights for bungalows, estate houses and converted garages

Why a roof window is usually too big

A bathroom is a small room, and a full roof window would need a light well from the slope down to the ceiling, which eats into the loft. The tube is far narrower, and the diffuser spreads what it delivers across the whole ceiling.

Trusses in the loft

Newer estate houses may have roofs of factory-made trusses, with timber diagonals running between the rafters and the ceiling joists. These leave gaps, though not unlimited ones, so the dome position is picked to put the tube between two trusses. If a diagonal is in the way, the dome can shift along the slope within limits.

Fan and light are separate jobs

A sun tunnel brings in daylight and does nothing to clear steam. The existing extractor stays where it is, and the tube is kept clear of the fan's ducting. Moisture is still a matter for the extractor, and a damp bathroom needs ventilation either way.

Landings on the same stretch of roof

In an estate house the bathroom and landing can sit close together, near the soil stack. When the two share a section of roof, one tube can serve the bathroom and a second dome, or a roof window over the stair, can serve the landing. Both are drawn onto the same loft plan so they do not meet in the same pair of trusses.

What you see afterwards

The diffuser is a flat or slightly domed disc, white or clear, level with the ceiling. By day the bathroom has an even glow, and the spotlights go back to being an evening tool.

The window as the way out

Rooms in a bungalow's roof sit close enough to the ground for a roof window to double as the escape route. Approved Document B sets the minimum opening size and how high the sill may stand from the floor. That reference is what the unit is chosen against, and the size you are quoted meets it.

Why a top-hung unit can suit

A window hinged at the top swings its lower edge outward and leaves a clear opening at the sill, so a person can climb out without catching the sash. A pivoting model leaves part of the opening taken up by the sash. For an escape route, the clear opening is what counts.

Where along the slope

The height of the sill in a sloping room matters. A window set too high needs steps to reach it, and one set too low leaves the roof edge awkward. We mark the position with the room furnished, so the sill sits where a person can use it.

Heat in a loft room

A loft room has less insulation between it and the weather than a ground-floor room, so the glass matters. The glazing choices, from double or triple panes to coatings that hold summer sun back, are set out on our energy efficient rooflights page.

Lifting the tiles and closing up

On fitting day we lift the tiles round the marked opening, frame it between the rafters, flash the unit to the tile in use, and line and paint the reveal inside. We take care of notifying Building Control. The tiles come off in order and go back in order, so the courses beside the frame look as they did.

Concrete interlocking tile

Concrete tiles interlock along their edges, and each overlaps the one below. A flashing kit for these has a profiled apron at the lower edge that follows the tile shape, with side gutters that lap over the tile edges. We lift the tiles from the area, fit the frame to the rafters, and relay the tiles tight to the kit.

Clay pantile

A pantile has a curved profile with a high roll and a low trough, so the gaps under it are bigger than under a flat tile. A pantile kit has a soft lead or aluminium apron that is dressed down into the trough by hand, and the roll tiles are cut to sit above the frame without leaving a gap. A cracked pantile is replaced from a matching reclaimed stock where we can.

Roof pitch and the kit

Every flashing kit has a pitch range. A shallow roof needs a different kit from a steep one, and a manufacturer's range limits which window can be used. We measure the pitch on the survey and pick the kit to match.

Underlay behind the frame

Under the tiles lies a membrane on the battens. At the opening it is cut and lapped up the sides of the frame, then turned over the top, so any water that gets behind a tile still runs to the outside. This hidden layer is one reason a window should be fitted to the roof as a whole and not simply set in a hole.

Where the weather finds a way in

The edge of a roof window is the most exposed part of the roof. The kit and the underlay beneath it matter more than the pane itself. A well-fitted kit takes water off the frame and on to the tiles below. A badly fitted one lets it in at the corners.

On the planning side, the planning guide explains when a rooflight on a house needs no application, and when it does, the application goes to North Yorkshire Council.