If you are planning a house extension in Manchester or Greater Manchester, the first question on your mind is almost certainly “how much is this going to cost?” The answer depends on the type of extension, the size, the materials, the finish level, and where exactly in Greater Manchester your property is located.
In this guide, we break down house extension costs across Manchester, Stockport, Salford, Bolton, Trafford, Altrincham, Sale, Bury, Tameside, and Rochdale so you can plan your budget with confidence before a single brick is laid.
House Extension Cost in Manchester: What to Expect in 2026
House extension costs in Greater Manchester are lower than the national average and significantly lower than London and the South East. Labour rates and material costs in the North West remain competitive, which is one of the reasons so many homeowners in the region choose to extend rather than move.
As a general guide, the average cost per square metre for a house extension in Manchester in 2026 is between £1,200 and £2,200 per m² depending on the specification. A basic finish sits at the lower end. A high end finish with underfloor heating, bi-fold doors, and premium fixtures pushes towards the upper end.
For a standard single storey rear extension of around 20m² to 30m², most homeowners in Greater Manchester should expect to pay somewhere between £35,000 and £75,000 including VAT, professional fees, and all finishes.
House Extension Costs by Type
Single Storey Rear Extension
This is the most popular type of extension across Manchester and Greater Manchester. It typically involves extending the kitchen or living area into the rear garden.
A 4m rear extension (approximately 12m² to 16m²) in Manchester costs between £25,000 and £45,000. A larger 6m to 8m rear extension (approximately 20m² to 30m²) ranges from £45,000 to £75,000 depending on the specification.
Key cost factors include whether you are installing a new kitchen in the extended space, the type of roof (flat roof versus pitched), and whether bi-fold or sliding doors are included.
Side Return Extension
Many Victorian and Edwardian terraced houses across Stockport, Salford, and inner Manchester have an unused side return alley. Converting this into usable living space is one of the most cost effective ways to gain extra room.
A side return extension in Greater Manchester typically costs between £15,000 and £35,000. Because the footprint is smaller and one wall already exists, the cost per square metre can be lower than a full rear extension.
Double Storey Extension
A double storey extension gives you additional space on both the ground floor and the first floor. The cost is not double that of a single storey because the foundations and roof are shared.
In Manchester, a double storey extension typically adds 50% to 75% on top of the single storey cost. For a 30m² footprint (giving 60m² of total new space across two floors), expect to pay between £60,000 and £120,000 depending on complexity and finish.
If you are planning to extend in the future, it is often more cost effective to build both storeys at the same time rather than adding the second storey later.
Wrap Around Extension
A wrap around extension combines a rear extension with a side extension to create an L shaped layout. This is popular with homeowners who want to create a large open plan kitchen and living area.
Costs for a wrap around extension in Manchester range from £50,000 to £100,000 depending on the total floor area, structural work, and specification.
Kitchen Extension
Kitchen extensions are among the most expensive per square metre because of the additional plumbing, electrical work, extraction, and fitted kitchen costs on top of the build itself.
A kitchen extension in Greater Manchester typically costs between £40,000 and £90,000. This includes the building work plus a mid range to high end fitted kitchen with appliances.
Bathroom Extension
Adding a new bathroom as part of an extension involves additional plumbing, waterproofing, tiling, and sanitary ware. Budget an extra £5,000 to £12,000 on top of the standard build cost for a fully fitted bathroom within your extension.
What Affects the Cost of a House Extension in Manchester?
Size
The bigger the extension, the more it costs. However, the cost per square metre often decreases slightly on larger builds because fixed costs like foundations, design fees, and scaffolding are spread across a larger area.
Location Within Greater Manchester
Labour and material costs vary across Greater Manchester. An extension in Altrincham or Hale may cost more than the same build in Bolton or Rochdale because of differences in local property values and the general cost of working in more affluent areas.
Ground Conditions
If your property sits on clay soil or has poor ground conditions, deeper foundations may be needed. This can add £3,000 to £10,000 to the total cost. Properties across parts of Bolton, Bury, and Tameside are more likely to encounter challenging ground conditions.
Access
Limited access to the rear of your property (common with terraced houses in Stockport, Salford, and central Manchester) can increase costs. If materials and machinery cannot be brought through the house easily, the build takes longer and costs more.
Planning Permission
Many single storey extensions fall under permitted development rights and do not require planning permission. However, if your extension exceeds permitted development limits, you will need a planning application, which costs £258 (the current standard fee for a householder application in England).
Double storey extensions, extensions near a boundary, or extensions on listed buildings or in conservation areas will almost always need planning permission.
Party Wall Agreements
If your extension is built on or near a shared wall with a neighbour (common with semi detached and terraced houses across Greater Manchester), you will need a party wall agreement. This typically costs between £700 and £1,500 per neighbour if a surveyor is required.
Building Regulations
All house extensions in Manchester require Building Regulations approval. This covers structural integrity, fire safety, insulation, ventilation, and drainage. Building control fees typically cost between £500 and £1,200 depending on the size and complexity of the build.
Professional Fees to Budget For
On top of the build cost, you will need to budget for several professional fees:
Architectural drawings are essential for planning applications and Building Regulations. Expect to pay between £1,500 and £4,000 for full plans depending on the complexity. Some architects charge a percentage of the total build cost, typically around 8% to 12%.
Structural engineer fees for calculations on steels, foundations, and load bearing walls typically cost between £500 and £1,500.
A full structural survey before starting work is recommended, especially on older properties. This costs between £400 and £800.
How Long Does a House Extension Take in Manchester?
Build times vary, but as a general guide:
A single storey rear extension of around 20m² typically takes 10 to 14 weeks from breaking ground to completion. A double storey extension takes around 14 to 20 weeks. A wrap around extension may take 16 to 24 weeks depending on the complexity.
These timelines do not include the design and planning phase, which can add another 8 to 16 weeks before construction begins.
Does a House Extension Add Value to Your Property?
In most cases, yes. A well designed and well built extension can add significant value to a property. According to industry data, a single storey extension typically adds between 5% and 10% to a property’s value. A double storey extension can add 10% to 20%.
With average property prices in Manchester sitting at around £250,000 in 2026, a well executed extension costing £50,000 to £70,000 could add £25,000 to £50,000 in value while also transforming how you use your home day to day.
For landlords and property investors across Greater Manchester, extensions are one of the most reliable ways to increase both rental yield and resale value.
How to Keep House Extension Costs Down
Get multiple quotes. Always get at least three detailed quotes from reputable builders before committing. Compare like for like and make sure each quote covers the same scope of work.
Plan thoroughly before starting. Changes made during construction are expensive. The more decisions you make at the design stage, the fewer costly surprises you will face on site.
Choose your specification wisely. A mid range finish can look excellent without the premium price tag. Focus your budget on the elements that make the biggest visual and functional impact, such as flooring, kitchen units, and doors.
Avoid peak season if possible. Spring and summer are the busiest periods for builders in Manchester. Starting your project in autumn or early winter may help you secure a better price and a faster start date.
Ready to Plan Your House Extension in Manchester?
Whether you are a homeowner looking to create more space, a landlord adding value to a rental property, or a property investor planning a refurbishment, getting the right builder is the most important decision you will make.
At Renovat Construction, we deliver house extensions, full property renovations, and refurbishments across Manchester, Stockport, Salford, Bolton, Trafford, Altrincham, Sale, Bury, Tameside, and Rochdale.
Get your free, no obligation quote today.
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