Guide prices in Dorchester
Pair of windows
Two roof windows into a loft room, flashings and linings
Three or four windows
Bigger loft rooms or stairwells
Balcony or combination
Balcony-style or stacked window combinations
Guide ranges for supply & fit. Your price is fixed in a written quote after we have seen photos or surveyed. Scaffold, access towers or a crane are priced separately if the job needs them, and building control fees, where a job needs them, are shown as their own line.
Where our fitters travel
Covering Dorchester means covering the people who live and work there, not a single postcode. We take on domestic and commercial jobs in DT1, DT2 and DT3, and are happy to quote further out in Weymouth and Yeovil. If your address sits between towns, tell us and we will confirm whether it falls in our normal area or needs travel set out separately on the quote.
Fit-only or supply and fit
If you have bought a loft roof window yourself, we check four things before fitting. First, the delivery: open it, look for chips, cracks and bent frames, and report any damage to the seller straight away. Second, the size, measured against the builder's opening rather than the external frame. Third, the flashing kit and the roof pitch range. Fourth, the maker's instructions, which set the fixings and sealing. Product warranty claims go to the seller and maker; our guarantee is for how it was fitted.
What we do on the day
- Underlay dressed and taped around every frame
- Rafters trimmed and doubled where the openings need them
- Insulation collars fitted so the room's insulation meets each frame
- Combination flashings — We order combination flashings where windows sit close together.
- Balcony-style windows — We check the rafters and the roof pitch before recommending balcony-style windows.
How a fitting day runs
Protection comes before tools. Floors, furniture and stairs get covered, and the ceiling below the opening is sheeted to catch dust. Up top, the fitters confirm the opening is square and the upstand or flashing suits what the maker specifies. Fixing follows, then weather-sealing into the membrane, felt or tiles. Only once the roof is tight do they turn to the internal reveal. Time on site for a loft roof window: one to two days, weather permitting.
Planning, building control and Dorchester
Replacing a rooflight in an English home is a controlled fitting: it has to be self-certified by a scheme-registered installer or notified to building control. We are not registered with a competent person scheme, so replacements we fit are notified with a building notice, and the new unit has to meet current energy limits. Adding a new one usually means a building regulations application, because joists or rafters are trimmed. On the planning side, most house rooflights are permitted development if they project 0.15 m or less; on a side slope the glass must be obscured and fixed unless the opening part is over 1.7 m above the floor.
Help us quote accurately
Each detail you send takes a question off our list. Photos inside and out show the opening and the ceiling. Rough measurements tell us the unit size. The roof covering tells us how it will be sealed in. Access notes tell us whether a tower or scaffold is needed. A product link, if you have one, lets us check it against the opening. Your postcode, DT1 or nearby, confirms travel.
Common questions in Dorchester
Do you make good inside after fitting?
Yes, where the quote includes it. Internal finishing usually means lining the reveal with plasterboard, taping or skimming, and fitting trim where it meets the ceiling. Some people prefer their own plasterer or decorator to finish off, which is fine. The written quote spells out exactly where our work stops, so nobody is left guessing about who does what once the unit is in.
Does a rooflight need building regulations approval?
A new opening usually needs building regulations approval. A replacement is a controlled fitting: it must be self-certified by an installer registered with a competent person scheme or notified to building control. We are not registered with a scheme, so replacements we fit are notified to building control with a building notice, and the council's fee is shown on your quote.
Can you fit a rooflight in winter or when it is raining?
Yes, within limits. Cold is less of a problem than wet, because membranes, primers and sealants need a dry surface to bond. We plan fitting days around the forecast and may move a date if heavy rain is due. If the roof has to be opened up, it is not left overnight without a temporary weather seal, so the room below stays dry while the work is finished.
Questions before you commit? Send them over with your Dorchester postcode and we will answer them plainly, with a quote alongside.

