Stocksbridge skylights and rooflights for steep-street terraces, stone attic rooms and old rooflights

Same opening or larger

A unit that matches the old opening goes in with the least disturbance to the roof. A larger unit needs the opening widened or lengthened, and the rafters either side are the limit. How far an old opening can grow is covered on the larger-rooflight replacement page.

Trimming the rafters

Widening an opening means cutting a rafter or more, and the load is carried round the new opening by trimmers fixed between the rafters either side. That changes the roof structure, so the work is notifiable building work. The rafter size and spacing set how large the unit can be before the trimming becomes heavy.

Stone and slate round the old frame

The old frame was flashed into a slate or stone-slate roof, and the covering round it may be worn or mended in places. The slates are lifted to a wider margin than the new frame needs, so that sound pieces can be laid back and the flashing sits on a tidy base. Sound slate from the opening is reused.

Keeping the house usable

With an old opening already in place, the work is quicker to stage than a new cut, but the attic floor and the stair below still need protecting. Sheets go down before the old frame is touched, and the loose slate and plaster that come out are carried through in bags instead of being thrown down the stairwell.

Planning for a bigger unit

Sheffield City Council receives any application for Stocksbridge. A house will normally take a rooflight without one, but a larger unit still has to sit within the permitted limits, and a listed house or a flat is different. You can read the limits in planning and Building Regulations for skylights.

When the old frame comes out

On the day of a larger swap, the old frame comes out, the rafters are trimmed to the wider opening, the new unit is flashed in and lined indoors. We give Building Control notice of the structural change.

One house, one slope

A rooflight goes in the slope of the house it lights. The roof of a stepped terrace has a break at each house, so there is no long continuous slope to share, and the opening stays within your own length of roof. That keeps the work separate from the neighbouring house.

Shade from the step

A higher neighbour's gable, or a chimney stack at the party wall, throws shade across the lower roof for part of the day. A rooflight placed near it gets less sun than one further along the slope, so the position is chosen with that shade in mind. Moving a unit a short way up or down the slope can matter more than the choice of glass.

Flashing along a step

Beside a wall that rises above the slope, the covering is lapped up the masonry and a stepped flashing is cut into the courses. The same method gives a clean junction where the frame meets the upstand. The frame is kept clear of the wall so the water has a path down.

Light for the landing

A roof window set over a landing between party walls drops daylight down the stair and onto the walls either side. Where the roof is too short for a window, a sun tunnel does the same from a small dome. The roof window over stairs and landing page shows the layout.

Sheets on a narrow stair

In a terrace the stair is also the way in, so the treads are covered before any ceiling is cut. The narrow width leaves little room to step round loose rubble, and a stair left clean at the end of each day stays safe to use while the roof is open.

Reaching a high stair

A stair that climbs a tall hillside house puts the landing window a long way above the floor. An electric opening rooflight that runs from a wall switch brings fresh air to the head of the stair without a pole.

Condensation or misting

Water on the inside surface of the glass is condensation, and it comes from the air in the room meeting a cold pane. Fog between two panes of a double-glazed unit is a different fault: the edge seal has failed, the haze sits within the sealed glazing, and that unit is what gets replaced. A new unit deals with both. For what causes each, read the rooflight condensation page.

What the new glazing does

Modern units pair two or three panes with argon or a similar gas fill, a coated inner face and a warm-edge spacer, all held in a thermally broken frame. A figure that is lower means less heat escapes through the unit. A roof window has to reach 1.4 W/m²K or Window Energy Rating band B, and a rooflight 2.2 W/m²K. A single-glazed unit fits neither, and the difference is felt in the room on a cold morning. A bed pushed against the slope, in particular, sits right beside that cold surface.

The frame matters too

The glass is only part of the unit. A frame can carry a barrier between its inner and outer faces, so the cold outside is not conducted straight through. The insulation round the lining is packed tight, which keeps the surrounding ceiling warm.

What the loft hatch shows

Before a unit is chosen, we look at the rafters from the hatch. Their spacing and depth show how much insulation fits round a new frame, and any damp staining on the timbers near the old rooflight shows where moisture has been settling. A damp-stained board around an old frame is a sign that the room has been short of ventilation.

Ventilating a room in the roof

A bedroom that is cold and humid needs air as well as glass. A roof window that opens lets damp air out, and an electric version with a rain sensor can be left to a switch. The figures behind this are worked through in how energy efficient skylights are.