On steep Georgian and Victorian roofs, fitting roof windows for a loft conversion is a sequence of careful steps. Access, structure, flashing and lining each affect the next.
Adding roof windows to a loft turns a dark space into a room, but the roof must be opened and closed up properly. On the steep slopes of Clifton's terraces and villas, access and weather planning matter even more. Here is how the work normally runs from the first measurement to the finished lining.
Planning positions and access
We begin by looking at the room layout, the rafters and the roof covering. Steep slopes mean scaffold or safe access is needed before any opening is made. Positions are chosen for light, sill height and structure, and the window has to be matched to a flashing kit made for the roof covering, such as slate or clay tile.
On older roofs the slates may be brittle or the battens uneven, which affects how the flashing is laid, so we check the roof around each position as well as the room inside it. If the slates are fragile we say so before work starts, because replacement slates may be needed around the opening.
Opening the roof structure
The covering is carefully lifted around the opening and the rafters marked. Rafters may need trimming and doubling up around the window so the roof stays sound. On older roofs the timbers can vary in size and spacing, so we check what is actually there before cutting. The opening is kept covered and weathertight between stages.
- Strip the covering around the opening
- Trim rafters and add supporting timbers
- Fix the window frame securely to the structure
- Cover the opening if work stops for the day
Flashing and the surrounding roof
The flashing kit joins the window to the roof and carries water around it. It has to be lapped correctly with the slates or tiles, which takes care on steep pitches and older materials. Most leaks around roof windows trace to flashing, sealing or the surrounding covering rather than the glass, so this is where we take our time.
Insulation, lining and vapour control
Inside, we insulate around the frame and fit a vapour control layer so warm room air does not reach cold timber. The reveal is lined neatly, usually splayed to spread daylight. Without proper insulation and vapour control, condensation can form around the opening, whatever the quality of the window itself.
- Insulation packed tightly around the frame
- Vapour control sealed to the lining
- Neat plaster or board reveals
- Splayed returns to spread daylight
Finishing and checks
We check how the window opens, how it seals and how the flashing sits, then clear the site. Ask for the window type, flashing kit and any structural work to be written down. Some work may need planning or Building Regulations checks — we advise before work starts. A good fitting treats the window, structure and roof as one job.
Before leaving we confirm everything works as it should, so there are no loose ends on a house where reaching the roof again means scaffold. We also show you how the window opens, how to clean it and how the blind or ventilation can be used, so it works properly from the first day.
Frequently Asked Questions
Do I need scaffold for roof windows on a steep roof?
Usually, yes. Safe access is needed to work on steep slopes and to keep the opening weathertight. We arrange it as part of the job and explain where it will go. We explain the plan beforehand so you know when it goes up and comes down.
Will my loft roof need strengthening?
Often some work is needed. Rafters are trimmed and doubled up around the opening so the structure stays sound. We check the timbers first and explain what is needed before cutting. Anything unexpected in the roof timbers is shown to you before work goes further.
Can roof windows go in a roof with slates?
Yes, with the right flashing kit for slate. Slate roofs need careful lapping and handling, especially if the slates are old. We check their condition before we start and tell you if anything needs attention.
Talk to our team about VELUX and roof window installation in Clifton
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.