Sun tunnels in Leicester

The best sun tunnel rooms share one trait: they are small and they are surrounded. Think of the long, narrow hallway of a Victorian terrace, with the front door at one end and a closed kitchen door at the other. Daylight reaches the first two metres and then gives up. Or the landing of a semi, where the bedroom doors are shut and the stairwell is a well of grey. Or the inside bathroom, the one with the extractor fan that comes on with the light because there is no window to open.

All of these rooms are under a loft, or under a roof space of some kind, and that matters. A tube has to travel through whatever sits between the ceiling and the roof, so a room directly under an accessible loft is the easy case. The tube drops straight down, and the work is quick and tidy. A room under a floored loft, or with a bedroom above it, is harder, and sometimes the answer is a different product altogether.

Our fuller walk through of the individual rooms is in the guide on sun tunnels for dark hallways and bathrooms. Here is the short version of how each one behaves.

Hallways and landings. The tunnel goes in near the middle of the space, where it lights both ends at once. The diffuser sits in the ceiling above the stairs or the passage, and the effect is a steady, even wash that makes the whole route feel wider. A hallway lit this way also shows up the colour of the walls properly, which people tend to notice first.

Bathrooms and shower rooms. Daylight in a bathroom changes how the room is used. You can see skin tone, a shaving mirror and the state of the grout. A tunnel over the shower or the bath means a bright room by day with nothing overlooking it, because the diffuser is frosted and no one can see in. Some makers offer a diffuser with a fitted light, so the same fitting serves after dark. We check what is available for the model on the quote.

Utility rooms, walk-in wardrobes and en suites. Small, windowless and under a loft is the pattern, and the tunnel does the same job.

The one room where we would think twice is any space that already has a decent window. A tunnel will add light, but a window with the right blind is usually enough, and the money goes further elsewhere. We say so at the survey, and in writing.

The longer the tube, the less light arrives at the bottom of it. Every metre of tube is a metre of surface for the light to bounce off, and every bounce loses a little. That is physics rather than a flaw in any maker's kit, and it is why the first thing a sun tunnel survey does is measure the distance from roof surface to ceiling.

For a typical house, that distance is short: the height of a roof space above a first-floor ceiling, or the depth of a loft above a landing. A short, straight tube delivers a great deal of its daylight. A long one, running through two floors or round several corners, delivers noticeably less. Makers publish length limits for each model, and we work inside them. We also tell you honestly when the route is near the edge of what the product does well.

How much light does a sun tunnel give? That depends on the dome size, the tube, the length, the number of bends, and the sky. A clear morning and a heavy November afternoon are different days. What stays constant is the order of the factors: dome size sets how much goes in, and the route decides how much of it comes out. Our short answer on how much light a sun tunnel gives covers it in more detail, and the figures to rely on are the maker's, because they are tested.

Where the tube runs matters as much as how far. A tube that faces north gathers softer, steadier light. One that faces south gathers brighter light at midday and, in summer, more heat in the dome. In practice the dome sits where the roof allows it, and the survey puts it as high on the slope as the flashing and the rafters permit, because height means a better view of the sky and less shading from neighbouring roofs.

One more point, on dim days. A sun tunnel does not store light. If the sky is dark, the room is dark, and the electric light is still there to be used. People who have one tend to notice the days it works, and forget the days it does not. That is a fair trade for a room that had no daylight before, but it is worth knowing before you book.

A sun tunnel is one of the faster installations we do, which is part of its appeal. That does not mean it is a casual job. There is a hole to cut in the roof and a hole to cut in the ceiling, with a loft route to be traced between the two, and the order matters. Here is the sequence on a typical pitched-roof job.

The survey and the route

We start in the loft. The survey traces the route from the chosen ceiling point to the roof, checks the rafters, the insulation, any cables or pipes in the way and the state of the roof covering. The ceiling point is set against the room: centred in a hallway, over the bath in a bathroom, wherever the light is needed. Then the roof position follows from the route. Only then is the tube and diffuser chosen, and the fixed written quote written. It lists what we found and how we deal with it.

The installation process

On the day, the sequence runs like this. We protect the room below with dust sheets and mark the ceiling point. On the roof, tiles or slates are lifted around the position and a small opening is cut between the rafters. The flashing goes in first and is laid into the roof covering as the tiles go back. The dome fixes to the flashing. Back in the loft, the tube is cut to length, fitted to the collar under the dome, run along the route and sealed at every joint. Insulation is laid back round the tube. Last, the ceiling is cut, the diffuser collar goes in, and the diffuser fits to the ceiling. The dust sheets come up and the room is left tidy.

On a typical house, that is usually a short job, measured in hours and not days, though the survey gives the real answer for yours. Our short answer on the time a skylight fitting takes covers the timing in more detail.

The loft is the part nobody sees afterwards, so it is the part that should be checked most carefully at handover. The tube should be supported, not hanging from its flashing. Every joint should be taped or collared. The insulation should be back in place. We photograph the finished run in the loft, and we are glad to show it to you.