Extensions in Maidstone
Single or double storey home extensions. Use the estimator to get an indicative cost range for Maidstone, then send one enquiry to have it matched to contractors who cover your postcode.
Last updated 22 Sept 2026 · Maidstone (ME14)
What extensions work involves
An extension adds floor area to the property: single or double storey, side, rear or wrap-around. The build cost is driven by the floor area, the structural work, the glazing and — more than most people expect — the level of finish.
Extension costs are driven by floor area, glazing, groundworks and finish level.
Estimated cost
Most extensions projects we hold cost data for fall between £25,000 and £45,000. Single-storey rear
The estimator for this service isn't available yet.
Estimated range only. The actual price depends on site-specific factors such as access, condition and specification.
What changes the price
- Floor area
- Cost is usually discussed per square metre of new floor area, then adjusted for everything else.
- Number of storeys
- A second storey shares foundations and roof but adds structure, stairs and internal remodelling.
- Structural work
- Removing walls, steel beams, new openings and foundations near drains or trees all add cost.
- Glazing
- Large sliding or bifold doors and roof lights are a significant proportion of many extension budgets.
- Level of finish
- Kitchens, bathrooms, flooring and joinery vary enormously and are the easiest place for budgets to move.
- Services and drainage
- Moving a kitchen or bathroom, and building over or near drains, affects both cost and approvals.
Extensions in Maidstone
Maidstone addresses in our coverage data start with the ME14 postcode.
It sits within Kent.
When you submit a extensions enquiry for Maidstone, it is offered to contractors who have told us they cover that postcode and that they take this type of work. We do not publish contractor counts or local price statistics, because we only report figures we can stand behind.
What a contractor will ask about your property
- Roughly what floor area do you want to add?
- Single or double storey?
- Will the extension contain a kitchen or bathroom?
- Are you removing internal walls?
- Do you have drawings, or do you need them?
- What type of extension?
- Approximate floor area?
- Do you have plans or planning permission?
- What finish level are you expecting?
How a project usually runs
- 1
Design and drawings
Measured survey, layout options, drawings prepared.
- 2
Approvals
Planning or permitted development confirmation, building regulations, party wall where relevant.
- 3
Groundworks and structure
Foundations, drainage, walls, steel and roof.
- 4
Fit out
First fix, plastering, second fix, kitchen or bathroom, decoration and completion.
Permissions and regulations
- Some extensions fall under permitted development; many need planning permission. Size, height and position all matter.
- Building regulations approval is required, with inspections during the build.
- A party wall agreement is often needed where work is near or on a shared boundary.
- Building over or near a public sewer needs the water company's agreement.
Problems that commonly come up
- Drain runs discovered in the footprint of the new foundations.
- Tree roots or poor ground requiring deeper or engineered foundations.
- Finish specification chosen late, after the budget was set.
- Existing structure that needs work once opened up.
When you need a specialist
- A structural engineer is normally required for beams and foundation design.
- Party wall surveyors where a neighbour's wall is affected.
- Kitchen and bathroom fit-out often involves separate trades.
Related services
Extensions in nearby areas
Common questions
Do I need planning permission?
It depends on the size, height and position, and on whether the property has used its permitted development allowance. Confirm before committing to a design.
Why do extension quotes vary so much?
Usually because of the finish level and what is included — drawings, structural design, kitchen, flooring and VAT are common differences.
How long does an extension take?
The build is only part of it; design and approvals often take longer than people plan for. Ask builders for a programme, not just a price.
Is the estimate a quotation?
No. It is an estimated range to help you budget; a builder needs drawings and a site visit to price the work.
Get quotes for your project
One enquiry, matched to contractors who cover Maidstone and take extensions work. No obligation, and we never publish your details.