Velux Window Costs UK — What to Charge for Roof Window Supply and Fit in 2026

Velux Window Types and Price Ranges

Velux is the dominant brand but FAKRO, KEYLITE, and ROTO also manufacture to the same standard sizes. The type of window has the biggest single effect on price — here's how they break down.

Centre-Pivot (GGL / GGU) — Most Common

The standard manual centre-pivot opens by rotating around a horizontal axis at the mid-point of the sash. GGL has a timber inner frame; GGU is polyurethane — better in bathrooms or where condensation is an issue. For a standard FK06 (66 × 118 cm) window:

Top-Hung (GPL)

The top-hung sash opens outward from the bottom, giving a larger clear opening — popular where head clearance is tight and customers want to lean out. Slightly more expensive than centre-pivot on supply.

Electric Solar-Powered (GGU / GGL Integra Solar)

Electrically operated via remote or app, with a solar panel on the outer frame that charges an internal battery — no mains connection required. Popular for hard-to-reach windows where a customer can't comfortably reach the manual handle.

Integra Electric (Mains-Wired, Remote Controlled)

Mains-wired electric operation with rain sensor and remote. Requires an electrician to run a spur or the roofer to coordinate a first-fix electrical supply before the window goes in. Higher product cost, more co-ordination on site.

Flat Roof Window (CVP / CFP)

Fixed or opening units designed for flat or very low-pitch roofs (up to 15°). The upstand and curb are part of the unit. Installation is slower than a pitched-roof window — cutting through flat roof build-ups (OSB, insulation, waterproof layer) takes more time and care.

No separate flashing kit — the CVP/CFP has an integrated upstand and kerb. Waterproofing around the upstand is included in labour.

Roof Terrace / Access Window (GXU)

The GXU opens to a full 45° to give access to a flat roof terrace. It's a specialist product — structural implications at the opening, heavier frame, and often needs two people to handle on the roof. Quote these individually after a site visit.

How Window Size Affects the Price

Velux uses a code system for sizes: the two letters give the width group (C = 55 cm, F = 66 cm, M = 78 cm, P = 94 cm, U = 114 cm) and the two digits give the height. So CK04 is 55 × 98 cm, FK06 is 66 × 118 cm, and MK08 is 78 × 140 cm. Larger windows cost more in materials, weigh more to handle on the roof, and require more tile disturbance to fit — all of which push labour up too.

The table below shows centre-pivot GGL/GGU fitted price ranges across three common sizes. These include a standard flashing kit.

Ranges reflect regional labour variation, roof complexity, and tile type. Higher end applies to profiled tiles (concrete interlocking, clay pantile) that need a more expensive EDP flashing kit, or where rafter noggins are required.

Flashing Kits — Always Quote as a Separate Line Item

The flashing kit is what waterproofs the joint between the window frame and the surrounding roof covering. Getting it wrong is expensive — a leaking roof window causes ceiling damage fast. There are three main categories for pitched-roof windows:

The EDW suits plain concrete or clay tiles and natural slates. If the roof has profiled interlocking tiles — Marley Ludlow, Redland 49, clay pantiles — you need the EDP, which has a deeper skirt to bridge the profile. Using EDW on a profiled tile roof is a common cause of callbacks.

Conservation flashings (EDL/EDJ) sit lower in the roof plane, reducing the visible projection of the window from outside. Required in some conservation areas even where planning permission isn't needed for the window itself. Always confirm with the local planning authority if in doubt.

What the Installation Involves

Understanding the process helps you spot hidden costs before you quote rather than absorbing them on the job.

Externally: mark the cut line, strip tiles to create a working area around the opening (typically 3–4 tiles each side and above), cut through sarking board or breathable underfelt, check rafter centres and fit noggins if necessary, install the window frame per Velux instructions, fit the flashing kit in sequence, relay tiles and cut any that need trimming to fit the new opening, re-bed any disturbed ridge or hip tiles.

Internally: cut back plasterboard or lath and plaster around the opening, fit the internal lining/reveal (a separate Velux accessory — the BDR lining kit). The BDR kit creates the angled plasterboard splays that funnel light into the room. Supply only cost is £150–£350 depending on size; fitting adds another half day of labour if a plasterer is required to skim.

Painting and finishing of the internal lining are outside the roofer's scope — make this clear in your quote. If the customer asks you to include it, you'll need to price in a decorator or plastering subcontractor.

Labour Time and Day Rates

A single standard centre-pivot window on a straightforward plain-tiled roof at a sensible working height typically takes a roofer and a labourer half a day (4 hours on site). Add time for:

• Profiled interlocking tiles — slower to strip and re-lay, add 1–2 hours
• Noggins required between rafters — add 1–2 hours depending on access
• Lath and plaster internally rather than plasterboard — add 1 hour internally
• Fitting a lining kit (BDR) at the same time — add 1.5–2 hours
• Electric window with mains supply needed — co-ordinate electrical first fix before returning to complete the window fit

For three or more windows in a run (e.g. a loft conversion with a bank of windows) you achieve some economies: tiles are already stripped, materials are on the roof, and you're in a rhythm. Expect a full day for three windows. Price each window, then apply a small discount for quantity rather than quoting a blanket day rate — it shows the customer they're getting a deal and maintains your margin transparency.

Roofer day rates in 2026 run £250–£400 per day depending on region (higher in London and South East, lower in the North and Midlands). A labourer adds £150–£200 per day. Build these into your hourly rate calculation — don't show them separately to the customer.

Scaffold and Safe Access

Working at height legislation requires a safe means of access to the roof. For most domestic roof window jobs on a standard two-storey house you can use a properly anchored roof ladder and a tower scaffold or ladder for initial access. However, if the property is three storeys, has a steeply pitched roof (>45°), or the eaves are too high for a standard extension ladder to reach safely, you'll need tube-and-fitting or system scaffold.

Scaffold hire for a single-window job on a two-storey house where a tower can reach: typically not needed. Full scaffold for a three-storey or awkward elevation: £600–£1,500 depending on the size of the structure and how long it needs to stay up.

Always itemise scaffold as a separate line on the quote. Customers understand it's a third-party cost and it stops them querying the labour charge if they see a chunky total. Get a fixed scaffold price from your regular scaffolding contractor before including it — don't estimate.

Planning Permission and Building Regulations

Most domestic roof window installations fall under permitted development and do not require planning permission, provided they meet all of the following criteria:

• The window does not protrude more than 150 mm beyond the existing roof plane when measured from the roof slope
• The window is not on a roof slope that faces a highway and forms the principal elevation of the house
• The highest part of the window is no higher than the highest part of the existing roof
• Side-facing windows within 1.7 m of the floor level of the room below must be obscure glazed and non-opening (or opening above 1.7 m)

Permitted development rights are removed for listed buildings, some Article 4 directions in conservation areas, and some new-build plots where the developer removed PD rights via condition. In conservation areas the permitted development rules above still technically apply for roof windows, but local authorities vary in how they interpret the "principal elevation" rule — advise customers to confirm with their local planning authority before you start.

Building regulations: a new roof window opening is a "material alteration" and should comply with Part L (energy efficiency) — double or triple glazed units are standard on all current Velux product and will meet the U-value requirement. If the loft is being converted to a habitable room (separate project) then full building regs apply to that project. For a simple replacement or new window in an existing habitable room, notify your building control if in any doubt — a competent person self-certification scheme covers structural work but not always roof windows in isolation.

Quoting Tips: What to Check Before You Price

Never quote a roof window job over the phone or from photos alone. You need to see the roof. On a site visit, check:

Tile type and condition

Plain clay, plain concrete, interlocking concrete, slate, clay pantile — each needs a different flashing kit and strips at a different rate. Check that the surrounding tiles are in good enough condition to be re-laid. If they're brittle or the nibs are worn, price in some breakage contingency or include a tile allowance.

Rafter centres and spacing

Standard post-war timber roofs have rafters at 400 mm or 600 mm centres. Velux windows are designed to fit between standard 600 mm centres without cutting rafters. On older properties you'll often find irregular spacing — sometimes 450 mm, sometimes closer. If the window doesn't fit the rafter bay cleanly, you need to fit trimmer rafters (noggins) or cut and re-support an existing rafter, which adds time and structural responsibility. Identify this before you price.

Existing insulation and underfelt

Cold roof construction with mineral wool between the rafters: straightforward. Warm roof with rigid insulation boards between and above the rafters: cutting through will disturb the thermal envelope and you'll need to reinstate insulation around the window frame. Some warm roof build-ups are very deep — check the rafter depth and construction before committing to a price.

Internal ceiling and lining situation

What's the internal ceiling like? A simple flat plasterboard ceiling in a bedroom means cutting a hole and the customer's plasterer makes good. An ornate lath-and-plaster ceiling in a Victorian terrace takes longer to cut carefully and there may be a listed building implication. Confirm who's responsible for internal making good in writing.

Electrical supply route for electric windows

For mains-wired Integra windows, the electrical supply needs to be at the window location before you fit the unit. Agree the programme with an electrician in advance — if you're subcontracting the electrical work, get a fixed price and include it (plus your margin) in the quote, or specify it as a customer-supplied item. Solar Integra models avoid this complication entirely.

Upsells That Add Real Value

A roof window visit is a good time to upsell additional work. Customers are already committed to having a tradesperson on their roof and are receptive to suggestions that improve the finished result.

Internal Lining and Reveal Kits (BDR)

The Velux BDR lining kit creates the angled plasterboard splays around the window that funnel light into the room and give a professional finish. Without it, the customer is left with a rough opening around the frame. Supply only is £150–£350 per window depending on size. Add half a day's labour to fit (£150–£250), plus any plastering and painting costs. Present this as the "proper finish" option and most customers will take it.

Velux Blinds

Velux manufactures a range of blinds that clip directly into the window frame — blackout roller blinds, pleated blinds, and solar-powered versions. A standard manual blackout roller blind in a common size retails at £80–£150 trade. Solar-powered blackout blinds are £150–£250 trade. Fitting takes 20–30 minutes per window as they clip in without tools. Include them as an option on every quote — the margin is decent and customers nearly always want blackout in a bedroom.

Secondary Glazing or Draught Sealing on Existing Windows

If the customer has older single-glazed roof windows (common in properties built before the mid-1990s), offer secondary glazing or replacement. A single-glazed Velux replacement with a current double-glazed unit costs £500–£900 fitted — a significant improvement in heat retention and noise. Secondary glazing panels for existing old Velux units run £150–£300 per window and fit internally without going on the roof.

Annual Maintenance and Re-Sealing

The rubber seals and flashings on a roof window need checking every five years or so, particularly around the flashing joints and the weathering collar. Offer an annual roof inspection as a paid service — £80–£150 per visit — that covers a visual check of all roof windows, gutters, and ridge tiles. It keeps you front of mind for future work and catches problems before they become emergency call-outs.

Quick Reference: 2026 Velux Window Costs UK

All prices exclude VAT. Scaffold costs (£600–£1,500 if required), lining kits (£150–£350 supply), blinds (£80–£250 supply), and internal plastering/decoration are additional. Regional labour rates vary — apply your own day rate to refine.