Two roof windows together can brighten a loft room a great deal. Whether they fit depends on the rafters and the roof, and here is what we look at in Patchway.
Loft conversions on Patchway's semis and bungalows often start with one small roof window and end up wanting two. Placing them side by side is usually possible, but it affects the roof structure and the weatherproofing, so it needs to be planned as a single job instead of two separate ones.
Rafter spacing and strength
Cutting an opening interrupts the rafters. For a pair of windows, some rafters may need trimming and doubling up to restore strength around the openings. The existing spacing influences which sizes and layout work best. We measure from inside the loft and explain the structural work before it is agreed.
On a bungalow loft, the roof pitch and ceiling height decide how much window you can usefully fit. We look at where people will stand and sit, because a window set too low or too high is a common regret that is hard to undo afterwards.
A kit made for the pairing
Two windows next to each other need a combined flashing kit, matched to the roof covering. Using two single flashings would leave a weak joint between them. VELUX and similar roof windows are supplied with kits for various coverings, so the correct kit is chosen after we check your tiles on site.
Hipped roofs and the layout
On a hipped semi, the main slope is often the best place for a pair, because it offers the width. Hip slopes are shorter and narrower, which limits what fits. We consider the room beneath too: where the windows sit relative to floor, ceiling and furniture affects light and the feel of the space.
Lining, insulation and the room inside
The area around the openings must be lined and insulated properly, with vapour control to limit condensation. This is what keeps a loft room comfortable and the surrounding timbers dry. It is also what makes the finished room look neat, with straight splays and clean lines around both windows. The work may need planning or Building Regulations checks, and we advise before work starts.
- Rafters trimmed and doubled up where required.
- One combined flashing kit for the pair.
- Insulation and lining fitted around both openings.
- Roof made weathertight at the end of each day.
What to ask any installer
Ask how the rafters will be dealt with, which flashing kit is used, and how the roof is protected while open. A clear answer covers each of those. On wide estate roads, access is usually simple, so you should also be told how the room and your belongings are protected.
It also pays to ask whether the work is done in stages that keep the roof closed overnight. A proper installer plans the opening so the roof is never left exposed to rain, and tells you what protection goes inside the room as well.
Frequently Asked Questions
How far apart should the windows be?
That depends on the rafter spacing and the flashing kit. Some kits allow windows almost touching, others need a gap. We choose the arrangement that suits your roof and the room, then confirm it on site.
Will two windows make the room too cold?
Modern roof windows are well insulated, and the lining and insulation around the openings are done to suit. A well-fitted pair should not cause problems, but the detailing around them is what makes the difference.
Can I add a second window later?
Often yes, if the first one is in a sensible position and the flashing kit allows it. Sometimes the first window has to be refitted to match. We look at your existing window and explain the options.
Talk to our team about VELUX and roof window installation in Patchway
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.