Velux Windows Horsham

A single Velux rooflight supplied and fitted costs £600–£1,000; two windows £1,100–£1,600. The price depends on the window size, whether it’s manual or electric, the flashing kit for your roof covering, and any internal making-good. Larger or specialist rooflights and dormer conversions cost more. We match the correct product and flashing to your roof type and confirm a fixed price after survey. See our detailed Velux cost guide and, if you’re converting the loft, our loft conversion roofing guide.

Usually not — rooflights that sit in the plane of the roof slope are generally permitted development and need no permission, provided they don’t project more than 150mm above the roof and don’t exceed the highest part of the roof. The exceptions are listed buildings, some conservation areas, and roof slopes facing a highway, where consent from Horsham District Council may be required. We confirm what applies to your property during the survey. Our planning permission for roofing guide and conservation area guide cover the detail.

Not necessarily. Most ‘leaking Velux’ problems are actually failed flashing around the window rather than the window itself — the flashing kit that seals it into the roof degrades or was poorly fitted, and water gets in around the frame. In that case renewing the flashing solves it far more cheaply than replacing the unit. Sometimes it’s a perished seal or a blocked drainage channel, both fixable. We diagnose the actual cause rather than defaulting to a new window, and only recommend replacement where the unit itself has genuinely failed — often worth it on very old windows regardless.

A straightforward replacement of an existing rooflight takes half a day to a day. A brand-new installation — forming a new opening in the roof — takes one to two days depending on the roof structure, covering and internal finishing. Slate and clay roofs take a little longer than concrete tile because the covering is more delicate to cut into and re-dress. We confirm the programme in the quote. If it’s part of a loft conversion, the rooflight work is coordinated with the wider job — see our loft conversion roofing guide.

Yes — we install rooflights on natural slate, clay tile and concrete tile roofs, using the correct flashing kit for each covering so the window seals properly into the roof. Slate and clay need more care: the covering is cut and re-dressed around the window, and the flashing has to be dressed correctly to stay watertight, which is where cheap installations fail. On period and conservation properties, conservation rooflights with a slimmer, more traditional profile are often the appropriate choice. We match the window and flashing to the roof rather than forcing a standard kit onto every covering.

Building Regulations set minimums for rooflights serving habitable rooms — for light and, where the room needs a means of escape, for the openable area — so the right size partly depends on the room’s use. Beyond that, it’s about the light and proportion you want and what the roof structure allows without cutting a rafter unnecessarily. We advise on the largest sensible size for your rafter spacing and the room’s needs during the survey. Getting this right at the planning stage avoids compromises later, especially if the rooflight is part of a loft conversion.

Not when it’s installed correctly — a properly fitted rooflight with the right flashing kit is a standard, warranty-safe part of a roof, and Velux windows carry their own manufacturer guarantee (typically 10 years on the window). What causes problems is poor installation: the wrong flashing, a botched cut, or inadequate re-dressing of the covering, which leads to leaks that no warranty covers. Our installations carry our written workmanship guarantee alongside the manufacturer’s window guarantee, so both the unit and the fit are covered. Correct installation is what protects the roof around it.