How much does an extension cost in Gloucester?
Planning an extension? Post the job for free and it goes to local builders who cover your area. Only the builder who takes it on gets your contact details.
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Before you build
Most extensions need building regulations approval. That covers the foundations, structure, insulation, drainage, fire safety and ventilation, and it applies whether or not you need planning permission. You can use the council’s building control team or a private registered building control approver.
Some single storey and smaller rear extensions fall under permitted development, which means no planning application. There are limits on size, height, position and materials, and the rules are tighter in conservation areas and don’t apply to flats. Some houses have had permitted development rights removed by a planning condition or an Article 4 direction. If you’re unsure, you can apply for a lawful development certificate for certainty.
If you’re building on or near the boundary, or digging foundations close to a neighbour’s house, the Party Wall etc. Act 1996 may apply. You have to serve notice on your neighbour before work starts, even if you have planning permission.
Check where your drains run too. Building over or within 3 metres of a public sewer needs the water company’s approval.
If you already have drawings, approvals or structural calculations, say so in your job. A builder pricing from full drawings can give a firmer figure. Without them, the first quote will be an estimate. The Planning Portal has more detail on extensions.
What to include when you post
An extension is a big job, so the more you can share, the more useful the first conversation will be. Include:
- The type: single storey, two storey, side return or wrap-around
- Rough size and what the room will be used for
- Whether you have drawings, planning permission or building regulations approval
- Whether you have structural calculations from an engineer
- Photos of the area where it will go, including the house wall and the ground
- Any drains, manholes or trees nearby
- Whether you share a wall or boundary with a neighbour
- Access for machinery and deliveries, and your ideal start date
What to ask
Ask for a detailed written quote, broken down by stage, so you can see what’s included. Check:
- Who deals with building control, and who arranges inspections
- Whether electrics, plumbing, heating, plastering, flooring and decorating are included
- What’s excluded, such as kitchen units, bathroom fittings or party wall surveyor fees
- How extra foundation depth will be charged if the ground turns out to be poor
- The payment stages, tied to finished work rather than dates
- Who removes waste, and whether skips are included
Ask whether any electrical work will be done by someone registered with a competent person scheme. Make sure you get the building control completion certificate at the end, as you’ll need it when you sell.
Not quite the right job?
See every job on our Builder page, or post it anyway and describe it in your own words.
Before a tradesperson starts work
Registrations
Some work must be done by a registered professional. Work on a gas boiler, cooker or fire must be done by a Gas Safe registered engineer, which you can check on the Gas Safe Register.
Our business check
Limited companies are checked with Companies House and sole traders upload their insurance certificate. Trade registrations are confirmed by the tradesperson when they sign up.
Get the price in writing
Ask for a written quote that sets out the work and the price before anything starts. Your contract for the work is with the tradesperson.
Questions
What people tend to ask before booking this job. For anything specific to your home, ask the tradesperson who takes it on when they get in touch.
Some extensions fall under permitted development and some don't. It depends on size, height, position, your type of house and if you're in a conservation area. Check with the council for your area or your architect before work starts. The Gloucester area is split between several councils, so make sure you contact the right one.
For a large job, yes. Ask for a written quote that breaks down what is and isn't included, so you're comparing like with like.
Planning is about whether you can build it: size, appearance and the effect on neighbours. Building regulations are about how it's built: structure, insulation, drainage and fire safety. Most extensions need building regulations approval even when no planning application is needed.
If the Party Wall etc. Act 1996 applies, you must serve formal notice before work starts. Even where it doesn't, it's worth talking to them early about access, noise and deliveries.
Not by law, but you'll need drawings for building regulations and any planning application. An architect, architectural technician or designer can produce them. A structural engineer may also be needed for beams and foundations.