If you are pricing up a single storey extension in Rochdale, Bury, Oldham or anywhere else in Greater Manchester, you will find plenty of vague answers online. This guide sets out realistic local figures for 2026, explains what pushes a quote up or down, and covers the extra costs people often forget.
For a straightforward single storey extension built to a good standard, most Greater Manchester homeowners should budget somewhere between £1,700 and £2,400 per square metre for the build itself. That means a typical 4m x 5m rear extension of 20 square metres usually lands between £34,000 and £48,000 before VAT, fees and fitting out. Local labour rates are lower than London and the South East, but material prices are broadly national, so the gap is smaller than many people expect.
A basic shell with a flat roof, standard foundations and minimal glazing sits at the lower end. A pitched roof, large sliding or bifold doors, structural steels to open up the existing house and a full kitchen fit-out will push you towards the top end or beyond. As a rough sanity check, if a quote comes in well under £1,500 per square metre, ask hard questions about what has been left out.
Two extensions of identical size can differ by £20,000 or more depending on specification and site conditions. The biggest swing factors are the roof type, the amount and quality of glazing, whether you are knocking through into the existing house, and what the new space will be used for. A utility room needs far less than a kitchen diner with underfloor heating and an island.
Ground conditions matter more than people realise, particularly across parts of Greater Manchester with clay soils, old mine workings or high water tables. If the building inspector asks for deeper foundations, that cost appears after the dig starts, so a sensible builder will include a provisional sum for it rather than pretending it cannot happen.
The build price is only part of the picture. Architectural drawings for a single storey extension typically cost £1,200 to £2,500, structural engineer calculations £400 to £900, and Building Regulations fees around £600 to £1,000. If you need full planning permission rather than building under permitted development rights, add the council application fee and a longer timescale, usually eight weeks or more for a decision.
On top of that, allow for a party wall agreement if you are attached to a neighbour, skip hire and site welfare, and VAT at 20 per cent if your builder is VAT registered. Most importantly, hold back a contingency of around 10 per cent of the build cost. Old houses in this part of the world hide surprises, from unrecorded drains to walls with no real foundations, and a contingency turns a crisis into an inconvenience.
The most common reason quotes vary wildly is that builders are pricing different things. One includes plastering, electrics and decorating; another stops at watertight shell. Before you approach anyone, get drawings done, then ask each builder to price the same specification and to itemise what is included and excluded, with provisional sums clearly marked.
Ask how they handle payment too. A reputable local builder will work to staged payments tied to completed work, not a large deposit upfront. Check they carry public liability insurance, ask to see a recent local job, and speak to the homeowner if you can. In Greater Manchester there is no shortage of builders, so take the time to find one who communicates well, because you will be talking to them daily for two to three months.
Most single storey extensions in Greater Manchester take 10 to 14 weeks on site from dig to decoration, assuming no major ground problems. Add two to four months beforehand for design, approvals and lead times on windows and doors.
Often not, as many rear extensions fall under permitted development rights, which allow up to 3 metres deep on a semi or terrace and 4 metres on a detached house, subject to conditions. It is still worth applying for a lawful development certificate so you have proof for when you sell.
Not necessarily. Groundworks can be slower in wet weather, but good builders work year round and you may find shorter lead times outside spring and summer. The design and approval stage takes months anyway, so starting the paperwork in autumn for a new year build often works well.
A quick chat is usually enough to establish whether your project is a good fit for Honeyman. Drawings, sketches or a postcode all welcome.