Velux Rooflight Installation Costs in Horsham
Velux windows — and equivalent rooflights from other manufacturers — transform loft spaces and dark upper rooms. Installation costs in Horsham vary primarily by window size, the number of windows being installed, and the roofing material involved. Here's what you should expect to pay in 2025.
| Installation Type | Typical Cost | Notes |
|---|---|---|
| Single standard Velux (550×780mm) | £600–£900 | Including window unit, flashing kit and labour. Most common on Horsham semis. |
| Single large Velux (780×1180mm) | £800–£1,200 | Including unit and flashing. Price rises with structural opening requirements. |
| Two windows, same visit | £1,000–£1,600 | Significant saving vs two separate visits. Labour is the biggest variable. |
| Replacement only (existing opening) | £350–£600 | Replacing an existing failed Velux in the same opening — no structural work. |
| Natural slate or clay tile roof | Add £100–£200 | Period-specific flashing kits cost more. Tile matching required around opening. |
What's Included in a Velux Installation
A complete Velux installation in Horsham should include: the window unit itself, manufacturer's flashing kit specific to your tile type, structural work to create or modify the opening (if required), felt patching around the opening, insulation to the reveals, and making good the internal plasterwork. Be wary of quotes that omit the flashing kit or internal finish — these are where costs are often hidden.
Does Tile Type Affect the Cost?
Yes, significantly. Velux manufacture specific flashing kits for different tile profiles — concrete interlocking, clay plain tile, natural slate, profiled clay and so on. The standard EDW flashing kit for concrete interlocking tiles (the most common type on Horsham's post-war estates) is the most affordable. Flashing kits for natural Welsh slate or clay plain tile on Victorian properties cost more, and the additional care required to avoid damaging reclaimed tile stock around the opening adds to the labour cost.
Planning Permission for Velux in Horsham
Most Velux installations on standard Horsham properties don't require planning permission under permitted development rules, provided the rooflight doesn't project more than 150mm above the existing roof plane. Key exceptions: properties in Horsham's conservation areas (around The Causeway and Denne Road) require planning permission for rooflights on principal elevations; listed buildings always require listed building consent.
If you're in a conservation area, a roof-mounted rooflight positioned on a rear elevation — not visible from the highway — is usually permissible. A front-elevation rooflight on a conservation area property will almost certainly require consent. We advise on this as part of our survey.
Velux Replacement vs New Installation
If your existing Velux is leaking or misted (failed double-glazing), a straight replacement in the same opening is significantly cheaper than a new installation — typically £350–£600 versus £600–£900+. The key is whether the existing frame and flashing are in good condition. If the flashing has corroded or the frame has warped, it's usually more economic to replace both together than to attempt a repair.
The Right Time to Install a Velux
The most cost-effective time to install a Velux rooflight is when the roof is already being worked on for another reason. If you are having a re-roof, adding one or two Velux windows during the stripping and re-battening phase adds relatively little to the programme — the scaffolding is already erected, the roof deck is exposed, and the incremental labour cost is small. A Velux installed as a standalone job requires scaffold erection, felt patch, tile relay and make-good, which is why standalone installations cost proportionally more per window than multiple windows during a re-roof.
We plan Velux installations as part of our re-roof surveys and advise on the best placement for light and ventilation. Rooflights on south-facing slopes provide the most light but require solar control glazing in rooms that receive direct sun. North-facing rooflights provide consistent diffuse light and are often preferred for bedrooms and studies. We discuss both during the survey.
Getting the Work Done in Horsham
All surveys in Horsham are free with no call-out fee. We attend within 3–5 working days for planned surveys and aim to reach emergency call-outs within 2–4 hours. Every job receives a written, itemised, fixed-price quote before any work starts — no verbal estimates and no bills that exceed the accepted written quote.
We are NFRC registered and carry £5 million public liability insurance. All work carries a written 10-year workmanship guarantee backed by a named, verifiable local contractor. Guarantee and insurance documentation is provided on request before any survey visit.
We cover Horsham and the surrounding West Sussex area including Roffey, Broadbridge Heath, Southwater, Billingshurst, Pulborough, Storrington, Henfield, Crawley, Burgess Hill, Haywards Heath, East Grinstead and Worthing. Call 0140 358 1272 to arrange a free survey.
Velux Quote for Your Horsham Home
Free survey — we assess the opening requirements, advise on planning and give you a written fixed-price quote.
📞 Call 0140 358 1272Last reviewed: July 2026 by Horsham Roofing Experts.