How much does it cost to fit a Velux window?
Updated 6 October 2026 · prices for 2026
Typical cost to fit one Velux window
£1,380–£1,550
per window, fitted, including VAT (£1,150–£1,290 + VAT)
A new opening in a pitched roof, fitted from inside: the window, flashing and collar, trimming the rafters, and lined, skimmed reveals. Sizes CK04 to MK08.
Fitting one Velux roof window in a pitched roof costs about £1,380 to £1,550 including VAT (£1,150 to £1,290 before VAT) for the usual sizes. That's a new opening, fitted from inside, with the rafters trimmed and the inside reveals lined and skimmed. The window itself is only about a third of the price; the rest is the flashing, the timber and the fitting by a roofer, a carpenter and a plasterer.
What's in the price
- The window: a Velux GGL centre-pivot roof window, about £245 for a CK04 to £350 for an MK08 before markup.
- Flashing and collar: the tile flashing kit and the insulation collar that seal it to the roof.
- Trimming: the rafters are cut and doubled up round the opening, on joist hangers.
- Fitting: cutting in, fitting and flashing the window, about 6 hours.
- The reveals: plasterboard, beads and skim round the inside of the opening, about 5 hours.
Pricing it as a builder
Price the window, the flashing and the collar from your supplier. Then price the hours by trade: about 6 for the roofer to cut in, fit and flash it, about 2 for the carpenter to trim the rafters, and 5 for the plasterer. Check on the site visit whether it can go in from inside, or needs a tower or scaffold. Priced on its own, a job like this carries a small premium for travel, setting up, a minimum charge and part-used materials. Done as an extra while you're already on site, the same work usually costs a bit less.
How we priced it
We built the job in Bricken, the quoting app for UK builders, item by item: standard merchant prices for the window and materials, typical day rates for each trade, and a typical builder's markup (30% on materials, 35% on labour). Your builder will price it at their own rates, so get a few quotes.
Priced in Bricken at standard UK rates, then adjusted by Bricken's regional factors (from public 2025–26 build-cost guides and our own quotes). The factors are set for whole building jobs, so treat smaller regional differences as a guide.
Cost by region
| Region | CK04 (55 × 98 cm) | MK08 (78 × 140 cm) |
|---|---|---|
| London | £1,660£1,383 | £2,010£1,676 |
| South East | £1,550£1,291 | £1,730£1,444 |
| East of England | £1,450£1,210 | £1,620£1,354 |
| Midlands | £1,340£1,118 | £1,550£1,289 |
| North West | £1,310£1,095 | £1,470£1,225 |
| North East and Yorkshire | £1,240£1,037 | £1,470£1,225 |
| South West | £1,450£1,210 | £1,620£1,354 |
| Wales | £1,270£1,060 | £1,420£1,186 |
| Scotland | £1,380£1,153 | £1,550£1,289 |
What pushes the price up or down
Up
- Scaffold or a tower when it can't be fitted from inside (high roofs, steep pitches): often several hundred pounds.
- Bigger windows: an MK08 costs more than a CK04, and large PK, SK and UK sizes more again.
- Electric or solar opening, blinds and triple glazing.
- A balcony window (Velux Cabrio): a different job, several times the price.
- London prices: labour, parking and skips all cost more.
Down
- Replacing an old Velux with the same size: no new opening to cut and trim.
- Several windows at once: one visit, one set-up.
- Plastering the reveals yourself, or leaving them for a later decorator.
- Supplying the window yourself: the builder then charges for fitting only.
Questions
How long does it take to fit a Velux window?
About a day for one window: in our breakdown, 6 hours for the roofer to cut in, fit and flash it, about 2 hours trimming the rafters, and 5 hours lining and skimming the reveals inside. The skim needs to dry before it's painted.
Do I need planning permission for a Velux window?
Usually not: roof windows are normally permitted development if they don't stick out much beyond the roof. If the house is listed, in a conservation area, or the window faces the road, check with your council first.
Does fitting a new Velux need building regulations approval?
Cutting a new opening alters the roof's structure, so check with your local building control before the work starts. Your builder can usually arrange it.
What size Velux window do I need?
It depends on the rafter spacing and the room. The common sizes are MK04 (78 × 98 cm), MK06 (78 × 118 cm) and MK08 (78 × 140 cm); the price difference between them is small next to the fitting cost.
Is VAT included?
The big figures include VAT at 20%. If your builder isn't VAT-registered, the price before VAT is closer to what you'll pay.
How we price: each figure is a Bricken quote built from the sizes, at standard UK merchant prices and day rates, with a typical builder’s markup. Your builder’s price will differ: get quotes.