If you are thinking about adding space to a house in or around Aylesbury, the first question is nearly always what it will cost. There is no single answer, but there are honest ranges and a handful of factors that move the price more than anything else. This guide walks through them so you can budget sensibly before anyone sets foot on site.
For a single storey rear or side extension in Buckinghamshire, a sensible working figure is roughly £2,000 to £3,000 per square metre for a standard build with a mid range finish. A higher specification, with large glazed doors, roof lanterns, underfloor heating or a complex roof, can push that well above £3,000 per square metre.
As a rough example, a 4m by 5m kitchen extension (20 square metres) often lands somewhere between £45,000 and £70,000 once foundations, structure, roof, windows, plastering and first fix services are included. The kitchen units themselves, flooring and decorating are often priced separately, so check what any figure you are given actually covers.
Ground conditions matter a great deal. Much of the Aylesbury area sits on clay, which can mean deeper foundations than a standard trench, especially near trees. Your building control officer or structural engineer will set the depth, and deeper digs mean more excavation, more spoil to remove and more concrete.
Access is the other big one. Terraced and semi detached houses where materials have to come through the house or down a narrow side passage take longer to build. Drains running under the footprint may need diverting, and if you share a wall or are digging close to a neighbour, the Party Wall Act may apply, which can add surveyor fees.
The build itself is only part of the total. Before work starts you will usually need drawings, structural calculations and a Building Regulations application, and possibly a planning application. These fees vary but can easily add a few thousand pounds.
Electrics and plumbing for an extension should be done by properly certified trades. On our jobs, larger electrical and plumbing work goes to certified subcontractors, and that cost should be clearly shown in any quote rather than tucked away.
Many modest single storey rear extensions fall under permitted development, which means no full planning application is needed. In general, an attached house can extend up to 3m at the rear (4m for a detached house), with larger depths possible through the prior approval process. Conservation areas, listed buildings and properties where permitted development rights have been removed are different, and there are quite a few older village centres around Aylesbury where this applies.
Whether or not you need planning permission, an extension will almost always need Building Regulations approval. Check with Buckinghamshire Council or your designer before committing to a layout.
A useful quote is itemised: groundworks, structure, roof, windows and doors, services, plastering and finishing. Be wary of a single lump sum with no breakdown, or a figure that seems far lower than others, as it often leaves out things you will pay for later.
It also helps if the person pricing the job is the person who will be running it. At Florriet, whoever quotes your extension is the one who builds it, and you have one number to call from start to finish. Quotes are free with no call-out fee, and you can get in touch by phone, WhatsApp or the web form.
Most single storey extensions take somewhere between 10 and 16 weeks on site, depending on size, ground conditions and the weather. Time for drawings and approvals beforehand is extra and can add several weeks or more.
Usually, yes. A garage conversion uses an existing structure and roof, so the cost per square metre is often much lower than building from new, though it still needs Building Regulations approval.
Yes. We take on work within roughly 30 miles of Aylesbury, including Wendover, Tring, Thame, Buckingham and Bicester.
Free quote with no pressure. Call, or message a few photos on WhatsApp, and we will tell you straight what it will cost and how long it will take.