The answer
To install a sun tunnel, we protect the room, mark the diffuser position on the ceiling and carry that line into the loft and out to the roof. The dome base and flashing go in first, then the tube is cut and run through the loft, and the diffuser is set into the ceiling. Inside, the opening is filled, plastered and finished.
Marking the positions from the room upwards
How to install a sun tunnel starts indoors, in the room that needs the light. Floors and furniture are covered, and anything fragile is moved out of the way. We choose the spot for the diffuser, which on a landing or in a hall is often mid-way along the ceiling and in a bathroom is usually towards the centre, and mark it in pencil.
From the loft we then carry the line upwards. A plumb line or a long straight edge shows where the tube would meet the underside of the roof, and a look at the timbers around it shows whether a rafter or ceiling joist stands in the way. If one does, the dome usually moves a little along the slope so the tube slips between two rafters. If a timber must be cut instead, the job is structural. We notify Building Control.
Only when the two positions agree is anything cut. That is the order of work because a dome placed first and a diffuser second can leave a route full of bends, and bends cost light.
Fitting the dome and the flashing
On the roof, the covering is opened round the marked spot. On slate or tile, the slates or tiles are lifted and kept aside. On a flat roof, the felt, EPDM or GRP is cut back to the size of the base. The opening goes through the roof deck and between the rafters, and the base is fixed to the timber around it.
Weathering comes next. On a pitched roof, a flashing is dressed round the base and the slates or tiles are laid back over it, so water runs round the dome without finding a way under it. On a flat roof, the base sits on a low upstand, with the covering lapped up its sides and sealed. The dome is clipped or screwed onto the base last.
We do this part before any work inside is finished, so that the roof is weathered and the loft is closed to the weather as soon as the opening is made. A flat roof that needs a new covering soon is best done together with the sun tunnel, so the weathering is carried out once.
Running the tube through the loft
With the dome in place, the tube goes in. Sections are cut to length and joined from the dome downwards, with elbows where the route has to turn, or a flexible tube is pulled out to length and fitted taut. Joints are taped so no loft dust gets in, and the tube is supported so it holds its line between the base and the ceiling.
Loft insulation is kept in place around the tube, and in a cold loft the tube is wrapped as the maker's instructions direct. Cables and pipes are routed clear of it. The reasoning behind the choice of tube is set out in the guide to rigid or flexible sun tunnel routes, and the main fact is that, on a run of equal length, rigid tube delivers more daylight than flexible.
The ceiling diffuser and making good
The ceiling is the last place to be opened. A circular opening is cut in the plasterboard to the size of the tube, the diffuser frame is fixed to the tube, and the diffuser panel is set into it. The gap round the tube is sealed, so warm air from the room does not travel up into the loft.
Cutting plasterboard makes dust, so the room and the landing outside it are sheeted while it is done. Afterwards the edge of the opening is filled, sanded and left ready for paint, and the ceiling round it is finished as the quote agrees. If a light kit is wanted, the cable is brought to the diffuser before the ceiling is finished, so we ask about it at the start.
The room is then cleared, the sheets are taken up and the loft is left tidy, with the boards you had lifted laid back.
How long it takes, and who does the work
The time a sun tunnel takes depends on the roof covering, the length and bends of the run, how easily we reach the roof and loft, and the ceiling to be finished. Slate that must be lifted and relaid takes longer than concrete tile, and a long route through a boarded loft takes longer than a short drop through an open one. We tell you how the work will run once we have seen those four things in your house.
Northcrest Skylights installs sun tunnels for householders in Leeds, plus the towns on every side of it up to 30 road miles away. A free survey comes first, and then a fixed written quote for that room, naming the unit and its size. The finished work carries our 10-year workmanship guarantee. For the planning side, read whether a sun tunnel needs permission, and for the figures that go into a price, what a sun tunnel costs to install.
To book the survey, message us on WhatsApp at 07880 284133 with the name of the room. For the service as a whole, see sun tunnel installation in Leeds.