Why a terrace landing stays dim
A roof window over stairs puts daylight where a Leeds terrace has least of it. In a through-terrace or a back-to-back, the staircase often runs up beside a party wall, and the landing at the top sits in the middle of the house, a room with hardly any outside wall of its own. A small window at the back, or none at all, is all the daylight it has. The stairwell below it is deeper still, so a landing that looks bright on a summer morning goes grey by the time you reach the hall.
The roof is the one side of the house that nobody has built against. Above a landing there is usually nothing but rafters, felt and slate, which is why a roof window is the natural way to bring daylight into that part of the house. A rooflight set in the slope sends light straight down the stairwell, and the stairs, the landing and the doors off it all pick it up.
We start from this room. Our approach, set out on the page about starting with the darkest room, is to find the part of the house that gets the least daylight and then look at the roof above it. On a staircase, that roof is often only a short climb up the loft ladder.
The landing is the one room in a terrace that every other room opens onto, and it is often the last to get daylight.
Where the window sits in the roof slope
The window has to sit over the part of the stairs that needs the light, and that is not always the part you would pick from inside. In a house where the stairs run front to back, the landing may sit under the ridge, or it may sit under the lower slope of the roof, depending on how the roof is framed. Climb into the loft with a torch and look down at where the stair opening meets the ceiling. The window is set over that opening, or over the landing just beside it.
Three things in the roof then shape the position:
- The rafters. A roof window is made to fit between two rafters, or to replace the stretch of roof between them with a trimmed opening. Where a rafter falls in the middle of the stairwell, that rafter is cut, and trimmers across the top and bottom of the opening carry its load to the rafters either side. Because the roof frame is altered, the work is notifiable, and we notify Building Control.
- The ridge and the eaves. The window sits at a height in the slope where the flashing can be dressed into the slates properly, clear of the ridge above and the gutter line below.
- The covering. A slate roof and a tiled roof need different flashing kits, and stone slate needs its own detail. The kit for the roof above your landing is chosen before the window is ordered, and the guide to flashing kits for slate and tile goes through them.
Where the roof slopes down to the back of the house, the window faces the garden side. Where it faces the street, the front slope is what the neighbours see, and the planning page for roof windows explains what that changes. Both are covered in planning permission for a roof window.
The light well from roof to ceiling
The window sits in the roof, and the landing ceiling is somewhere beneath it. Between the two is a shaft, the light well, and the daylight travels down it before it reaches the stairs. In a house with a loft that has not been converted, the shaft is a box of plasterboard or timber lining that runs from the window frame down to a hole cut in the ceiling.
The shape of that shaft is what sets how much light arrives. A square, straight-sided well passes the light down like a chimney, and the walls soak up much of it on the way. A well that is splayed, with its sides leaning outwards towards the ceiling, lets the light spread out and widens the patch of landing that is lit. Our guide to roof window light wells and reveals goes through how the lining is built and finished, because the surfaces of the shaft matter as much as the glass at the top.
When the loft is deep
If the loft is tall and the landing is a long way below the window, the shaft is long as well. Length in the shaft shrinks the lit area on the floor, so the window may go as low in the slope as the roof allows, which shortens the well.
When there is no loft between
In a house where the stairs run up into a converted roof space, the window can sit almost directly above the stairs, with no shaft to speak of. A stair that rises into a loft room is the simplest case, because the glass is already part of the room it lights.
Choosing the window for a stairwell
A window over a staircase works harder than one over a bedroom. It is high, it is seen from below, and you will not be reaching for it every morning. That pushes the choice towards a few things.
Top-hung or centre-pivot
A centre-pivot sash pivots around its centre line and is chosen where furniture stands below it. A landing has none, but the stairs do have a rail and a drop, so the more useful question is the one about headroom. A top-hung sash is hinged along its upper edge and opens outward, so nothing projects into the space beneath it. On a stair that clearance is the useful part.
Size
The size follows the stair opening. A narrow window lights a narrow strip of the stairwell, while a wider one lights the landing and the top few treads together. Each maker states its size codes differently. A VELUX code reads the width from the letter and the height from the digits, and choosing the VELUX window size covers the codes. The written quote gives the size we fit.
Glazing
Double glazing is the starting point for a roof window, and a better U-value means a warmer landing. For a replacement or new roof window in an existing house, Part L sets a limit of 1.4 W/m²K, or Window Energy Rating band B, for the window. Over a stairwell, a window with a solar-control coating helps keep the landing cooler in the afternoon, because the heat rises to the top of the house. The glazing choices are laid out in full under energy efficient rooflights.
On a stair, the opening of the window and the rail below it are planned together.
Opening a window you cannot reach
A window over a stairwell sits well above the landing floor, and you cannot stand on the stairs and lean up to a handle. If it is only meant to light the stairs, it can stay shut. If it is also meant to let warm air out of the top of the house, there are three ways to make that practical:
- A handle you can reach. Some roof windows have a control at the top or bottom of the sash, and the choice depends on where the opening sits in relation to the floor of the landing.
- A pole. A long pole with a hook at the end catches the handle, so that a window above head height can be opened from the floor.
- An electric opening unit. Worked from a wall switch or a hand-held remote, it suits a ceiling nobody can reach. Rain sensors, fitted to many models, shut the window by themselves in a shower, which suits a window you cannot see from the stairs. The three ways of opening are compared in how an electric, solar or manual rooflight opens.
Opening the window matters for another reason: warm air gathers at the head of a staircase. A stairwell is a tall, narrow chimney of air in summer, and a window at the top lets it out.
Escape from the roof is a separate matter from this window. On a two-storey house with a loft conversion, the way out of the loft is a protected stair, and that is a separate question from the one on this page. Escape windows are covered by Approved Document B and serve rooms within a fixed height of the ground, and skylight planning and Building Regulations explains where they apply.
How the installation goes
A roof window over a stair is fitted from both sides of the roof, and it follows an order we keep to.
- We mark the opening from the loft, over the stair or the landing, and check the rafters on either side.
- The slates or tiles are lifted from the slope around the marked opening and set aside for the flashing.
- The opening is cut, the rafters trimmed and the frame set into the roof.
- The flashing kit is dressed into the covering around the frame, and the window is fixed and closed up.
- The light well is lined from the window frame down to the ceiling, and the ceiling opening is cut to match.
- The reveal is plastered and decorated to the finish agreed, and the staircase is cleared of dust sheets.
The stairs are the only way through the house, so we protect the treads and the banister before the first slate comes off. Because we are working above the stairs, the dust sheets go down first, and the ceiling is the last thing cut.
A roof window is a sealed weather detail in a slope, and a poor flashing is what makes it leak. That is why the covering and the kit are matched before the window is ordered, and why the guarantee page describes the 10-year workmanship guarantee on the finished window.
When a sun tunnel does the job instead
Not every landing suits a roof window. If the roof above is very low over the stairs, or the loft between the roof and the ceiling is full of tanks and ducting, the light well gets hard to build. In that case, a sun tunnel brings daylight down a narrow tube from a small dome on the roof, and it can often pass between rafters without the same structural work. It lights a landing or hallway well, but it does not open and it gives no air.
The choice between the two depends on the room, and our page on choosing between a sun tunnel and a roof window goes through it. For a landing with a clear roof above it, the roof window gives more light and can open. For a landing with a cluttered loft above, the sun tunnel is often the simpler fit.
You can find the rest of the options on the roof window installation page, which covers types, glazing and finishes. If you are weighing up what the job will involve, the answer on what a roof window installation costs sets out what moves the figure.
Getting a landing window quoted
We come out to look at the landing from below and the roof from above, then write up a fixed quote for the stairwell, with the window and its size on it. To get that moving, WhatsApp 07880 284133 a few photos of the stairs and the landing. A photo of the loft hatch and the underside of the roof helps too, since it shows what sits between the ceiling and the slates.