How much does rooflight installation cost? What drives the price

What are you paying for?

A rooflight price has more in it than the glass. On a typical job it covers:

• Labour for the fitting team, usually two people for anything but the smallest unit;
• Materials around the unit, such as timber, insulation, membrane, sealant or sealing tape, plasterboard and fixings;
• The rooflight itself, on supply-and-fit jobs;
• Access, from ladders and roof edge protection to scaffold and lifting gear where needed;
• Removal and disposal of old units and roof waste;
• Paperwork, meaning building control fees where they apply.

Two jobs that look alike from inside the room can be priced very differently because of what is going on at roof level.

Some items depend so much on the site that they appear as their own lines: scaffold or access towers, a crane or powered glass lifter for very heavy units, the final electrical connection, roof repairs beyond the area around the rooflight, and decorating after plastering. If your job needs any of them, the written quote lists them from the start rather than adding them on the day.

What are the guide price ranges?

The table below shows the guide ranges we work within for the most common jobs. They are the same figures used on our guide prices page and in the guide price tool.

Prices include VAT at 20%. Trade fitting rates are shown plus VAT. Tiers for each job are on our guide prices page.

Each range assumes ordinary access and a roof in reasonable condition, and assumes the job is what its label says. Where your job falls in the range depends on the drivers below, and the figure is fixed in the written quote after we have seen photos or surveyed.

Fit-only or supply and fit?

Fit-only means you buy the rooflight and we fit it, so the price covers labour and the materials around the unit. It suits people who have found a product they want or already have one. You carry the product risk: the right size, an undamaged delivery and the warranty sit between you and the seller.

Supply and fit means we source a suitable unit and fit it. The price includes the product, and sizing, delivery checks and product queries are ours to sort. On a new opening it also means the unit and kerb are sized together from the start. See fit-only installation for more on the first route.

Which parts of the job move the price most?

• The upstand. A sound kerb at the right height and size is the lowest-cost starting point. Raising, rebuilding or insulating one adds timber, membrane and time.
• A new opening. Cutting and trimming joists or rafters, and strengthening the timbers beside them, is the biggest single step up. A structural engineer may be needed for larger openings.
• The roof covering. Rubber and felt are patched differently from fibreglass, and asphalt or old, brittle coverings take more care to tie in.
• Size, weight and lifting. Large or walk-on glass may need more people, suction lifters or powered lifting gear.
• Access. A single-storey extension reached from a ladder is very different from a two-storey roof needing scaffold.
• Electrics. Electric units need a cable route and a qualified electrician for the connection.
• Building control. New openings, and replacements we fit in England and Wales, carry a council fee.
• Making good inside. Lining, insulating and skimming the reveal is part of most new openings; decorating is usually separate.

Does the type of rooflight change the fitting price?

Yes, because different units take different amounts of work to fit well:

• Fixed flat glass is the simplest: fix, seal, weather and finish.
• Frameless units need a very accurate kerb, because there is little frame to hide errors.
• Manual and electric opening units add hinges, actuators and, for electric units, a cable route and controls to set up and test.
• Walk-on and sliding units are heavy, often bespoke, and walk-on glass is structural, so the supporting kerb has to be designed for the load.
• Roof lanterns are assembled on the roof from glazing bars and panels, which takes longer than dropping on a single unit.
• Pitched roof windows involve the tiles or slates, the flashing kit and the underlay as well as the window.

The guide prices table splits these out, so you can see where each type sits.

Why do published cost figures vary so much?

Cost guides online are compiled in different ways. Some figures exclude VAT, some include it and many do not say. Some fitting figures include building the upstand and plastering, while others cover only dropping a unit onto a ready kerb. Some guides put London and the South East 20 to 30 percent above the UK average. When comparing quotes, line up what each one includes before comparing totals.

How do you get an accurate quote?

1. Tell us the job: fit-only, a replacement, or a new opening.
2. Send the product details if you have a unit, or the size of opening you want.
3. Send photos of the roof or kerb from outside, the ceiling from inside, and how the roof is reached.
4. Give the kerb measurements in millimetres, if there is a kerb.
5. Tell us the roof covering, if you know it.

Fit-only jobs are usually priced from that. Supply-and-fit, replacement and new-opening jobs get a free survey visit before the fixed quote. Leak investigation visits are charged, with the price confirmed before booking. Use the quote form to start, or read about new openings and replacements.

How can you keep the cost down?

• Keep a sound existing kerb where the new unit can use it; choosing a unit made for that kerb size avoids a rebuild.
• Line a new opening up with the joists to reduce trimming.
• Choose a standard size rather than a bespoke one, where the room allows.
• Group the work: two rooflights on one roof, or a rooflight fitted while the roof is being re-covered, share the set-up and access.
• Book the electrician for the same stage, so the ceiling is only opened once.

What we would not cut is the upstand height, the membrane detail or the insulation round the opening. Those are what stop the leaks and condensation that cost far more to put right later. Our fitting standard explains each one.

Questions