Velux roof windows installed to manufacturer specification — with correct flashing kits, rafter trimming, and full weather integration.
Roof windows transform dark loft spaces, but they're one of the most common sources of leaks when installed incorrectly. The flashing detail is critical — get it wrong and you'll have water tracking behind the tiles and into the ceiling below.
Velux manufactures specific flashing kits for different tile profiles. Using the wrong kit — or fabricating flashings from lead or felt — is a recipe for leaks. We always specify the correct kit matched to your exact tile or slate.
Installing a roof window usually requires trimming the rafters to create the opening. On a pitched roof, this means fitting trimmer rafters to maintain structural integrity. For flat roof skylights, the opening needs a proper upstand and kerb detail. If scaffolding is needed, we factor this into the quote.
Installing a roof window requires trimming rafters to create the opening. For standard single-window installations, the trimming follows Velux's guide. For larger openings or non-standard structures, we'll recommend a structural engineer.
Common questions about our skylight installation services.
A standard Velux roof window installation typically costs between £800–£1,500 including the window, flashing kit, and labour. Costs vary depending on window size, glazing specification, and whether structural trimming is required.
In most cases, Velux windows fall under permitted development and don't require planning permission, provided they don't protrude more than 150mm above the roof plane and aren't on a principal elevation facing a highway. Conservation areas have additional restrictions.
Yes. We install flat roof skylights and rooflights as part of our flat roof service. These are typically fixed-frame units with self-cleaning glass, installed with the correct upstand and flashing detail to prevent leaks.
Every Velux and skylight installation comes with our standard guarantee package: a 15-year workmanship guarantee, a 15-year manufacturer-backed materials warranty, and a 10-year insurance-backed guarantee (IBG).
The flashing kit creates the watertight seal between the window frame and the roof covering. A genuine manufacturer flashing kit is engineered for the specific tile or slate profile on your roof. Generic or improvised flashings are the number one cause of skylight leaks.
Yes. We cover the full DA, BR, SE, ME, and TN postcode areas including Sidcup, Orpington, Bromley, Dartford, Medway, Rochester, Welling, Chislehurst, and surrounding towns.
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