Roof Windows: Velux, Fakro & Keylite
Roof windows transform what a loft can do — turning a dark unused storage space into a usable bedroom, study or bathroom, or simply flooding a kitchen or stairwell with daylight. We fit the three major brands — Velux (the original and still the market leader), Fakro and Keylite — with the right choice depending on the application, the roof type and the budget.
Velux is the premium brand and our most common choice for residential work. The build quality, the integrated flashings, the after-sales support and the spare parts availability are all unmatched. Fakro is the value alternative — very similar performance for around 20-30% less, with a slightly less polished finish but a perfectly competent window. Keylite occupies the middle ground and has the unique built-in expanding thermal collar which simplifies installation and improves the seal around the frame.
Standard, Centre-Pivot & Top-Hung
The most common style is the centre-pivot window — the sash rotates on a horizontal central axis, which makes it easy to clean both sides from inside and lets you control the opening to keep rain out. Standard configuration on most loft conversion windows.
Top-hung windows open outwards from the bottom (the sash hinges at the top), which gives a much better external view because the sash is out of your eyeline when open. Better in bedrooms where you want a balcony-style view, but more difficult to clean and less common.
Conservation-style windows have an external glazing bar to mimic the appearance of older roof lights for listed buildings and conservation areas. Cost premium of 20-30% over standard, often required where planning conditions specify.
Installation: It's All About The Flashings
A roof window is only as good as the flashing kit that ties it into the surrounding roof. Velux supplies pre-formed flashing kits matched to specific tile or slate profiles — deep tile profiles get one kit (EDW), slate gets another (EDN), low-profile concrete tile gets another (EDP) — and these are designed to dress in over the surrounding tiles or slates and create a fully weathertight seal at the head, sides and sill of the window.
Installing a Velux without the matching flashing kit (or worse, with cement-based flashings) is a guaranteed leak waiting to happen. Every window we fit gets the manufacturer's correct flashing kit for the specific roof type. We also fit insulation collars around the frame to eliminate cold bridging, and dress in the breathable underlay correctly so the original membrane continuity is maintained.
Replacement Windows & Blinds
Older Velux windows from the 1990s and 2000s often need replacing today — the frame seals perish, the glazing units fail (mistted units, cracked panes), and the gas struts holding the sash open lose their gas. Modern Velux units are dramatically more energy-efficient than older models (triple glazing standard, U-values around 1.0 W/m²K vs. 2.5 on older units), and replacement is straightforward because the frame sizes have remained consistent for decades.
We can also supply and fit Velux blinds and shutters to existing windows — blackout blinds for bedrooms (essential in summer when the sun comes up at 4:30am), pleated translucent blinds for bathrooms, and external roller shutters for the upper-end specifications.
Frequently Asked Questions
Do I need planning permission for a Velux window?
Usually no — roof windows on the rear or side roof slopes are normally permitted development, provided they don't project more than 150mm above the roof plane. Conservation areas, listed buildings, and the front roof slope of any property may need planning permission.
How long does Velux installation take?
A single window is usually a one-day job. Multiple windows in the same roof can be done in 2-3 days. Replacement of an existing Velux is half a day to a day.
Will it leak?
Not if it's installed with the correct manufacturer flashing kit. Every leak we've ever been called out to on a roof window has been because the original installer used the wrong kit, no kit at all, or cement-based flashings.
Velux, Fakro or Keylite?
Velux for premium, long-term, best after-sales support. Fakro for value-for-money domestic installation. Keylite where you want the built-in thermal collar and slightly easier installation. All three are good choices when properly installed.
Can you fit Velux into a slate roof?
Yes — the EDN flashing kit is designed specifically for slate and gives a perfect weathertight finish. Slate installation takes slightly longer than tile because each surrounding slate needs to be carefully dressed in.