Swapping an old roof window for a new one is often straightforward, because the opening already exists. Still, the flashing, lining and surrounding roof need a proper look.
Plenty of post-war lofts and dormers around Kingsweston have a roof window that is now tired, misted or hard to open. Replacing it is often easier than starting from nothing, because the opening is already there. The details still matter, though. A new window sitting in a worn surround will not stay dry, so we look at the whole opening, not just the glass.
Why replace rather than repair
A misted window has a failed sealed unit, which cannot be cleared. A stiff or corroded frame, a window that no longer closes properly or one that lets in draughts are further reasons. If the old frame is sound, parts can sometimes be renewed. Often a full replacement is more sensible and gives better insulation. In a loft conversion the lining and insulation around the frame matter just as much.
Matching the new window to the opening
VELUX and similar roof windows come in standard sizes, and the best result comes from a new window of the same size, so the rafters do not need altering. If the old one is an odd size, we can adjust the opening, which may mean trimming and doubling rafters. We measure carefully before ordering anything. If the old frame is a different make, we explain how a matching new one will be sourced.
- Size and type matched to the existing opening
- A new flashing kit suited to your roof covering
- Sealing and insulation renewed around the frame
- Internal lining checked and made good
The flashing is the key
The flashing kit seals the window to the roof covering and has to match the tiles or slates. Reusing an old, bent or corroded one defeats the purpose of a new window. Most leaks around roof windows trace back to the flashing, the sealing or the roof covering around the window, not to the glass itself.
What we find when the old window comes out
The surrounding timbers, felt and insulation are exposed once the old frame is lifted. Sometimes they are fine, sometimes there is damp or rot that has been hidden for years. We show you what we find and explain what needs fixing, so the new window is not fitted into a problem. Wet insulation, if present, is replaced rather than dried and reused.
What to ask first
Ask how the new window will be matched to the opening, which flashing kit will be used, and what happens if damp timber is found. You should also expect to hear how the room will be protected and how the roof will be left. A clear, written description of the work is a good sign. Ask also how long the opening will be exposed, and how it will be covered if weather turns.
Frequently Asked Questions
Do I need to change the whole opening?
Not usually. If the new window matches the old size, the opening stays as it is. If the size or position changes, the rafters may need trimming and doubling up, which we plan before starting.
Why is my roof window misted between the panes?
Misting between the panes means the sealed unit has failed and moisture has got in. The glass cannot be cleaned out, so the unit or the whole window is replaced, depending on its age and condition. We explain which route suits your window after seeing it.
Will replacing the window stop it leaking?
Only if the cause was the window. Leaks often come from the flashing, sealing, condensation or the roof covering around it, so we find the real cause first and tell you what will cure it.
Talk to our team about VELUX and roof window installation in Kingsweston
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.