VELUX Window Installers › Cwmbran › Guide
A roof window looks like a simple swap of tiles for glass, but the opening cuts through the roof structure and the weatherproofing. On Cwmbran's post-war houses, a few checks before you commit will save a lot of trouble. This guide covers what we look at and what you can check from the loft floor.
The loft and the room it will serve
Start with headroom and layout. A window only helps if there is useable floor beneath it and a place to stand. We check the height to the ridge, the position of the stairs and where the window will sit in relation to the room. On the 1950s to 1970s semis around Greenmeadow and Henllys the loft is often deep enough, but the window position needs thought so you can actually look out of it.
The rafters and roof structure
The opening is cut through the roof, so rafters usually have to be trimmed and the edges doubled up to carry the load. In trussed roofs, the timbers are tight and the window position is limited by where they run. We check the structure from the loft first and tell you whether the opening is straightforward or needs more work. You can look from inside with a torch.
- Rafter spacing and direction across the planned opening
- Whether the roof is trussed or has purlins
- Condition of the timbers, with no rot or woodworm
- Space for lining and insulation around the frame
The roof covering and flashing kit
The window must be matched to a flashing kit made for your tile profile. Concrete interlocking tile, plain tile and slate all need different kits. A mismatch is the most common cause of leaks around a window. We identify the tile on site and order the kit to suit, so the opening is weathered by the correct parts and not by sealant alone.
Insulation, lining and condensation
A window opening is a gap in the insulation. The lining, insulation and vapour control around the frame all have to be done properly, otherwise the reveal turns into a cold patch that grows condensation and damp. That matters in cooler lofts such as those in Upper Cwmbran, where the air is damp. Good ventilation in the room helps, and we explain the finishing before work starts.
Permissions and the questions to ask
A roof window may need planning or Building Regulations checks — we advise before work starts. Beyond that, ask who is doing the rafter work, which flashing kit is specified and how the opening will be protected while the roof is open. A clear answer to each is a good sign. Ask also how the lining and insulation are being finished and who clears up afterwards.
Need velux window installers in Cwmbran? See our velux window installers in Cwmbran page, or call 07766 547309.
More Guides for Cwmbran
Common Questions
Can I check my loft before you visit?
Yes, from the loft floor only. Note the rafter direction, the ridge height and any damp or stains on the timbers. Do not go onto the roof. Photographs help us plan the visit, but we still look properly in person.
Will fitting a roof window affect the rest of my roof?
If done properly, no. The rafters are trimmed and doubled to carry the load and the flashing kit weathers the opening. A badly fitted window can leak into the room, which is why we check the structure first.
Does the roof window need special flashing?
Yes. The flashing kit is chosen for your tile or slate profile, and using the wrong one is a common cause of leaks. We identify the covering on site and fit the matching kit, not generic sealant.
Get a Quote in Cwmbran
Tell us what the roof is doing in Cwmbran and we will look at it. Call 07766 547309, message us on WhatsApp or use the form below.