Sun Tunnel Cost, Fitted

The kit itself

A sun tunnel kit has three visible parts: a dome on the roof, a reflective tube and a frosted diffuser in the ceiling. The diameter of the tube is the first choice that moves the price. A wider tube gathers and carries more daylight, and it costs more as a product. A narrower one suits a small landing or a cupboard and is cheaper.

Within one diameter there are still options. Some domes are clear and low, others are raised. Some diffusers are plain frosted discs and some are built to take a light fitting for the evening. None of these choices is dramatic on its own, but they are listed separately so you can see what each one adds.

Length of run and the loft

The distance between the dome and the diffuser is the single biggest driver of labour. Beneath a flat-roofed extension that distance is only a joist depth, so there is hardly a tube at all. Under a pitched roof, with a loft between the slates and the ceiling, the tube may have to travel a long way, and each extra length is more material and more careful jointing.

Then there is what shares the loft. Water tanks, pipework, cables and bracing timbers all sit in the way on some routes. Moving a cable or stepping a tube round a tank takes time, and a route that needs two elbows costs more than one that drops straight down. We trace the line at the survey so the quote reflects the loft you actually have.

Rigid or flexible tube

The tube type changes the price in two ways: the cost of the material and the time it takes to fit. Rigid lengths with fixed elbows deliver more light down a straight route. Flexible tube bends round obstacles and goes in quicker in a cramped space, but it carries a little less light for the same length.

Many runs use a mixture. If you want the choice explained room by room, our guide to rigid or flexible sun tunnels sets out when each makes sense, and the quote will say which sections are which.

Your roof covering

The flashing is made for a particular covering. Slate, plain tile, interlocking tile and pantile each take a different apron and different side pieces, so the right flashing kit is part of the price, not an optional extra. A flat roof takes a kerb dressed into the membrane instead.

The age and type of the covering matters as well. Lifting slates on an old roof calls for more patience than lifting modern tiles, because brittle pieces are easier to damage. Where a few extra slates or tiles are needed to make the finished roof look right, that is shown as its own line.

• Slate and plain tile need the most hand-dressing around the dome
• Pantile and interlocking tile use a profiled apron that matches the course
• Flat roofs need a kerb joined into the membrane, whatever it is made of

The ceiling and the finish inside

Inside the house the work is small but exact. The ceiling is cut to the diffuser, the trim ring is fixed and the gap is sealed so warm air cannot travel up the tube. In a modern plasterboard ceiling this is quick. In an older house with lath and plaster, the cut needs more care to protect the surrounding plaster, and it takes longer.

Decorating is a choice. If you would like the ceiling made good and painted around the ring, that is priced as a line of its own. If you would rather paint it yourself, we leave the ceiling clean and ready, and the quote shrinks accordingly.

Protecting the house

A sun tunnel is among the less disruptive jobs we do, but it still means a team on the roof, a team in the loft and a ceiling being cut on the landing or in the bathroom. Dust sheets go down over floors and stairs, a screen goes up round the work where there is room, and the dust is cleared before we leave each evening.

These things are built into the quote and listed, so you can see them rather than assume them. The roof is closed up weathertight before the team leaves, whatever stage the job has reached.

Access to the roof

Reaching the roof safely is another line. A single-storey roof with a clear garden may need only ladders and a working platform. A taller house, a roof reached only through the house, or a steep slope can call for a tower or scaffold. It gets its own line, which lets you judge what the height costs.

It is worth saying at the survey if parking is tight, or if the only way to the back of the house is through a narrow passage. Those details go into the plan for each day, and they save surprises later.

Rules and paperwork

A new opening in a roof needs Building Regulations approval, and for a notifiable job the application to Building Control is ours to make. Rooflights on houses are usually permitted development, so many sun tunnels need no planning application. A flat, a maisonette, a listed building or a street under an Article 4 direction is different, and the council confirms.

Our planning permission guide explains the conditions in full. If the route into a bathroom or hallway is your reason for looking, sun tunnels for bathrooms and hallways covers what is particular to those rooms.

When a roof window costs more or less

A sun tunnel is often the smaller job, because the opening in the roof is round and narrow and the structure is disturbed very little. A roof window needs a larger opening, trimmers cut into the rafters and a room beneath the slope, so it generally involves more work. That is not always the deciding point. If the room sits under the roof, a window may be what you want, and the extra work buys a view and fresh air.

We compare the two properly in sun tunnel or roof window, and for a window-side figure there is the roof window cost guide.

Single-storey and flat roof jobs

When the ceiling sits directly beneath a flat roof, a tunnel is mostly a dome, a kerb and a diffuser with a very short tube between them. There is little loft work, so labour falls. What takes its place is the roof membrane. The kerb has to be joined into whatever covers the roof, whether that is felt, rubber or fibreglass, and each of those is sealed in its own way.

The state of the covering counts for a lot here. An ageing flat roof makes a poor foundation for a new dome, and the sensible quote may show re-covering as an option beside the tunnel. Doing both in one visit gives you one weathering detail and one guarantee. Can a sun tunnel go on a flat roof looks at the set-ups in more detail.

Why a low price can be the expensive one

A tunnel that is cheap to buy and quick to fit can still be dear to live with. If the tube is left bare in a cold loft, the warm air from the room can leave droplets inside the run, and a damp ring appears on the ceiling around the diffuser. Putting that right means returning to a job that should have been finished once.

The reverse is also true. A line on the quote for insulating and sealing the tube looks like extra money, yet it is the part that keeps the ceiling clean for years. Ask where the insulation is, how the joints are sealed and who checks the work before the loft hatch is closed.

What the quote leaves for you to decide

Some choices are yours, and a good quote lists them as options and not buried in the total. These are the usual ones:

• A built-in light fitting in the diffuser, for use after dark
• Painting the ceiling around the ring, or leaving it for you to decorate
• A raised dome in place of a low one
• Adding an extractor fan in a bathroom while the loft is open
• Re-covering a worn flat roof in the same visit

Each is a separate line with its own cost. That means you can choose a lighter job now, and still know what the fuller one would have cost.

Value over time

A sun tunnel has no moving parts and no electrics, so there is very little to maintain. The dome benefits from a rinse now and then. After that the work is done, and the saving is in the hours you no longer spend with a bulb on in a landing or bathroom.

How that shows on your bills depends on the room and on how you use it, so we do not promise a figure. What we can say is that the glazing and the kerb are built to current thermal standards, and the opening is sealed so it does not become the cold spot in the ceiling.

Reading two quotes side by side

When you have two quotes, put them next to each other and go line by line. A lower total can mean a shorter tube, a cheaper flashing, no insulation on the loft run or a ceiling left unfinished. None of that is visible on the day. All of it shows up in the years after, in a damp stain round the diffuser or a cold circle on the ceiling.

Our written quote answers each of those, each cost on its own line, with a plan for each day. To start, use the quote form further down, or read the full sun tunnel installation page first.