Guide prices in Dorchester
Small fixed unit
Opening cut, joists trimmed, upstand built, roof covering made good, plasterboard reveals ready for decoration
Medium fixed unit
As the small unit, with a larger opening up to about 1 × 2 m and additional trimming
Large or opening unit
Bigger structural work or an electric opening unit
Guide ranges for supply & fit, including structure and making good; building control or warrant fees extra. 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.
Is your address covered?
If you also own a property or a business unit in Weymouth, Yeovil or Poole, that is no problem. We can survey and quote both, and where it suits, line the fitting days up together. Every address is reached by fitters travelling to it from their current jobs, and DT1, DT2 and DT3 sit comfortably within that pattern.
Fit-only or supply and fit
Which works out better, buying your own or letting us supply? It depends on what you value. Buying your own gives you control of the product and what you pay for it. Letting us supply puts the whole job, unit and fitting, under one written quote. On a customer-supplied unit we still measure it against the opening, look at the upstand, and inspect the condition it arrived in. Warranty on the product sits with whoever sold it, while the fitting carries our own guarantee.
Included in the work
- Insulated upstand built square, level and to the maker's height
- Joists or rafters trimmed with new timbers to carry the load around
- Opening marked out, covering stripped back and the deck cut cleanly
- Warm or cold roof build-up — We find out whether the roof is insulated above or between the joists before designing the upstand.
- Which way the joists run — We check the direction and size of the joists before fixing the rooflight's position.
Fitting your rooflight, step by step
On the day, you need to be in at the start and at the end. In between, the fitters get on with it. They will want the room below cleared where possible, a parking spot if you have one, and somewhere to set the unit down safely. After checking the opening and the upstand or flashing, they fix a new rooflight, seal it and finish the inside. Packaging and any old unit leave with them unless the quote says otherwise.
Do you need permission in Dorchester?
In England, a new rooflight opening generally needs building regulations approval because the roof structure is altered and the glazing must meet energy rules: 2.2 W/m²K for a rooflight in an existing home, or 1.4 W/m²K (or WER Band B) for a roof window. Planning is often not needed on a house: permitted development covers rooflights that stand no more than 0.15 m proud of the roof slope and sit below the highest part of the roof. Flats, listed buildings and areas with an Article 4 direction are different, so we check your address first.
Details that speed up your quote
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 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.
Can you replace an old dome without redoing the whole roof?
Usually, yes. If the existing kerb is sound, level and tall enough, a new unit can often sit on it with a fresh seal to the roof covering. If the kerb is rotten or too low, we rebuild it and patch the covering around it rather than stripping the whole roof. This is checked at the survey and included in the written quote, so you know the full scope first.
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.
Get in touch with the details of your Dorchester property and we will explain what the job involves and what it costs.

