Velux and roof window installation in Canterbury typically costs £900–£1,800 supplied and fitted, depending on window size and roof covering. The flashing kit that seals the window to the tiles is what makes or breaks the job — most roof-window leaks come from a wrong or badly-fitted flashing kit rather than the window itself.
What Does a Velux Installation Cost in Canterbury?
A supplied-and-fitted roof window in Canterbury typically runs £900–£1,800. The window itself is only part of the cost — the flashing kit, any internal plastering and making good, and the labour to cut and frame the opening all add up. Larger windows and awkward roof coverings cost more. Fitting into an existing pitched roof is straightforward; forming a new opening in a finished room costs more.
Building Regulations Part L and Part F govern the thermal performance and ventilation requirements for new roof windows, and manufacturers specify a tile-profile-matched flashing kit for a weathertight seal.
Source: Building Regulations Approved Documents L and F
Why Roof Windows Leak (and How to Avoid It)
When a roof window leaks, the window is rarely the culprit — it's the flashing kit around it. Each window needs a flashing kit matched to the tile profile (flat, low-profile or deep-profile), correctly interleaved with the surrounding tiles and soakers. Fit a generic or wrong-profile kit, or dress it badly, and water tracks in at the top corners. On Canterbury's varied roof coverings — from Kentish peg tile to concrete interlocking — matching the kit to the tile matters.
Do You Need Planning Permission for a Roof Window?
For most Canterbury homes, roof windows on the rear or side that don't project beyond the roof plane are permitted development and need no planning permission. But if your property is listed or in one of Canterbury's conservation areas, you may need consent — and a conservation officer may require a specific low-profile or heritage-style rooflight. We check before quoting.
Can You Fix a Leaking Roof Window?
Yes — many of our roof-window jobs are repairs to leaking windows fitted badly by someone else. We strip back the flashing, check the soakers and underlay, and re-fit the correct flashing kit for the tile. In most cases the window itself is fine and only the seal needs putting right.
Need a roofer in Canterbury you can trust?
📞 Call 0122 763 4920