Guide prices
Like-for-like swap
Old dome or unit removed and disposed of, new glass rooflight fitted to the existing sound kerb
New upstand and swap
Old kerb taken off, new insulated upstand built, roof covering made good, new unit fitted
Opening or large unit
Electric or larger replacement, including making good inside
Guide ranges for supply & fit; building control notice fee extra in England and Wales. 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.
Coverage in and around Dorchester
Looking at a property near Dorchester but not quite in it? We work across DT1, DT2 and DT3 and outwards to Weymouth, Yeovil and Poole. Give us the full postcode when you get in touch, because access, parking and the route for a large unit all depend on the exact street. Those details shape the quote for any job around Dorchester.
Fit-only or supply and fit
Your unit or ours, the fitting standard is the same. For supply and fit we choose a replacement rooflight to suit the roof and price it with the installation. For fit-only we work with what you have, after confirming it arrived undamaged, that it matches the builder's opening, and that the upstand will sit at the height the maker asks for. Report any transit damage to the seller, as the product cover is theirs and the maker's. Our written guarantee applies to the fitting itself.
What the job includes
- Internal reveal made good where the old trim or plaster was damaged
- Packers, an adaptor or a new insulated upstand where the old kerb falls short
- New unit bedded, fixed and sealed exactly as its maker shows
- Dome to glass upgrades — We check that the opening and kerb suit a flat glass unit before quoting a dome-to-glass swap.
- Energy rules for the new unit — We make sure the replacement meets the current energy limit, not just the old unit's performance.
From arrival to clean-up
Fitting days start with a look at the sky. If rain is due, the order of work changes so the roof is never left open to it. A typical day for a replacement rooflight runs like this: set up access, protect the room, open up the roof or prepare the existing kerb or frame, check sizes, fix, seal, then finish inside. On jobs that take more than a day, the opening is weather-sealed overnight. The last hour goes on tidying, waste removal and a walk-round with you.
Planning, building control and Dorchester
Two sets of rules matter in England. Planning: a rooflight on a house is normally permitted development if it projects no more than 0.15 m and stays below the highest part of the roof, but flats, listed buildings and Article 4 areas need checking. Building regulations: new openings need approval for the structure and energy performance, and a replacement is a controlled fitting. We are not registered with a competent person scheme, so we notify replacements to building control with a building notice and put the council's fee on the quote.
Help us quote accurately
Keep it simple. Two or three photos, outside and inside. Approximate sizes. What the roof is made of. Anything awkward about getting up there, such as a conservatory below, a narrow side path or no parking. If you bought the rooflight online, the link or model name. Then your postcode in or around DT1. That is enough for a first price.
Common questions in Dorchester
Can you fit the replacement rooflight I bought online?
Yes, fit-only is one of our core services. Send the product link or spec, photos of the roof and rough sizes, and we can usually price it from those. Before fitting we check the delivery for damage, which should be reported to the seller, plus the size against the builder's opening and the upstand height. The product warranty stays with the maker or seller, and our guarantee covers the fitting.
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.
What upstand height and roof pitch does replacement rooflight fitting need?
It depends on the product. Manufacturers usually specify a minimum upstand height above the finished roof surface, and a minimum pitch on the glass so rain runs off. We follow the maker's figures for your unit rather than a rule of thumb. If your existing kerb or roof falls short, we explain the options, such as raising the upstand or choosing a unit with built-in pitch.
Got a unit waiting to go in, or need one sourced? Either way, start with your Dorchester address and a couple of photos.

