Velux Window Installation Cost UK: Roof Windows and Skylights

Velux window installation cost in the UK runs from around £900 to £1,800 supply-and-fit for a standard roof window in a pitched tile or slate roof, rising to £1,800 to £3,500 for a flat-roof rooflight where the waterproofing is more involved. Add scaffolding or any structural change and a complex job can pass £4,000. “Velux” is a brand name most people use for any roof window, and the window itself is only part of the bill; the flashing kit and a day or so of skilled labour usually cost as much again. This guide breaks the price down so you can budget before you call a roofer.

Velux window installation cost at a glance

These are indicative 2026 figures for a single unit. Window prices vary little across the country; it is labour that moves, with London and the South East at the top of the range.

What you are actually paying for

A roof window install is three costs stacked together.

• The window unit (£350 to £900). Price climbs with size, glazing spec (double vs triple, solar-control or laminated glass) and the opening style. A fixed rooflight is cheapest, a manual centre-pivot is the standard choice, and electric or solar-powered opening windows cost more because they add a motor and wiring.
• The flashing kit (£80 to £250). This is the weatherproof collar that seals the window to your roof covering. There are different kits for slate, plain tile and profiled tile, so the type of roof you have sets the price. Skimping here is the usual cause of a leak later.
• Labour (£350 to £600). A single window in an existing rafter opening is roughly a one to one-and-a-half day job for a two-person team. Cutting a new opening, which means altering rafters and adding a structural trimmer, takes longer and costs more.

What pushes the price up

Several things move a job from the bottom of the range to the top:

• Cutting a new opening rather than replacing an old one. Altering the roof structure needs trimming around the rafters and, on larger openings, sign-off under Building Regulations. Our guide to planning permission and building regs explains when approval is needed; most like-for-like roof windows are permitted development, but check before you commit.
• Access and scaffolding. A safe working platform is often required, especially on a two-storey house. See our roof scaffolding cost guide for what that adds.
• Flat roof versus pitched. A flat-roof rooflight needs a timber upstand or kerb and careful waterproofing where it meets the membrane, which is why it sits £900 or more above a pitched-roof unit.
• Number of windows. Fitting two or three in one visit spreads the scaffolding and set-up cost, so the per-window price drops.

How to budget and get a fair quote

Get at least three written quotes and make sure each one lists the window model and size, the flashing type for your roof, labour, scaffolding and the making-good of the surrounding roof and plaster. A quote that just says “supply and fit Velux” hides too much. Confirm the roof around the opening is sound first, because there is no sense cutting a new window into a covering that is near the end of its life; a quick roof inspection settles that. If you are adding windows as part of a wider upgrade, our roof windows, dormers and insulation overview sets the options side by side.

For the manufacturer’s own sizing and product range, VELUX UK is the authoritative reference, and the Planning Portal roof windows page covers the permitted development rules.

Frequently asked questions

How much does it cost to fit a Velux window in the UK? A standard roof window in a pitched roof costs around £900 to £1,800 supply-and-fit per unit in 2026. That covers the window (£350 to £900), the flashing kit (£80 to £250) and one to one-and-a-half days of labour. Flat-roof rooflights cost more, typically £1,800 to £3,500.

Why is a flat-roof rooflight more expensive than a pitched-roof one? A flat roof needs a timber upstand or kerb built up, plus careful waterproofing where the rooflight meets the membrane. That extra material and skilled labour pushes a flat-roof rooflight roughly £900 or more above an equivalent pitched-roof window.

Do I need planning permission for a Velux window? Most like-for-like roof windows are permitted development and do not need planning permission, though there are limits on how far they project and rules for conservation areas and listed buildings. Cutting a new opening may need Building Regulations sign-off, so always check before work starts.

Does the type of roof affect the cost? Yes. The flashing kit is matched to your roof covering, so slate, plain tile and profiled tile each use a different kit at a slightly different price. The condition and pitch of the roof, and whether an opening already exists, also affect labour.

Is an electric or solar Velux worth the extra cost? Electric and solar-powered opening windows cost more because of the motor and wiring, but they are worth it for out-of-reach windows or bathrooms where a rain sensor that closes the window automatically is genuinely useful. For a low, easy-to-reach window a manual unit saves money.

Can one roof window be fitted in a day? Fitting a single window into an existing opening is usually a one to one-and-a-half day job for a two-person team. Cutting a brand-new opening, altering rafters or adding scaffolding extends that, so confirm the timescale in your quote.