How Much Does a House Extension Cost in Surrey?
A house extension in Surrey typically costs between £30,000 and £150,000 depending on the type, size, and specification. Surrey prices sit above the national average due to higher labour costs and the quality of finish expected in the area.
Getting the budget right from the start is one of the most important steps in any extension project. This guide gives you realistic Surrey price ranges for every type of extension, explains what drives cost, and tells you what to watch for when comparing quotes.
House Extension Costs in Surrey by Type
| Extension Type | Typical Surrey Cost | Notes |
| Single storey rear extension | £30,000 to £60,000 | Most common type. Size, glazing, and finish drive cost. |
| Double storey extension | £55,000 to £110,000 | Higher cost but adds significant floor area on two levels. |
| Side return extension | £35,000 to £65,000 | Popular in terraced houses. Reclaims the alley beside the kitchen. |
| Wraparound extension | £60,000 to £120,000 | Combines rear and side return. Creates large open plan ground floor. |
| Over-structure extension | £40,000 to £80,000 | Builds above an existing garage or ground floor. No new foundations. |
| Infill extension | £45,000 to £85,000 | Fills an L-shaped gap in the house footprint. |
These figures cover design, planning, build, and fit-out to a good standard. They do not include VAT (charged at 20% on most extension work) or professional fees for structural engineers and architects, which typically add 10% to 15% on top of the build cost.
What Drives the Cost of a Surrey Extension?
Size
Cost per square metre is the standard way builders price extension work. In Surrey, expect to pay between £2,000 and £3,500 per square metre for a well-specified single storey extension, and £2,500 to £4,000 per square metre for a two-storey project. Larger extensions do not always cost proportionally more per square metre because some fixed costs (design, planning, scaffolding, groundwork) spread across more space.
Specification and finish
The specification has an enormous impact on cost. Bi-fold or sliding doors, roof lanterns, underfloor heating, bespoke joinery, and high-end kitchen or bathroom fittings can each add thousands to the final figure. A standard finish and off-the-shelf products keep costs lower. A bespoke finish with premium materials pushes toward the top of the range.
Structural complexity
Extensions that require significant groundwork, underpinning existing foundations, removing load-bearing walls, or working with awkward site conditions cost more. Older Surrey properties, particularly Victorian and Edwardian terraces, often present structural challenges that add to the budget.
Planning and design fees
Most extensions above 6 metres (single storey) or any size (two storey) require planning permission. Architect fees for drawings and planning submission typically run between £3,000 and £8,000 depending on complexity. Structural engineer fees add £1,500 to £3,000. Building regulations applications cost £200 to £500.
Surrey labour rates
Labour rates in Surrey are 15% to 25% above the national average. This is consistent across trades: bricklayers, plasterers, joiners, plumbers, and electricians all charge more in Surrey than in most other parts of England. Factor this in when using national cost calculators.
Cost Per Square Metre: Surrey Benchmarks
| Specification Level | Cost per m² (Surrey) | What It Gets You |
| Budget | £1,800 to £2,200 | Basic materials, standard windows, simple layout, limited glazing |
| Mid-range | £2,200 to £3,000 | Good quality materials, double glazed units, solid flooring, decent kitchen or bathroom |
| Premium | £3,000 to £4,500+ | Bi-folds, roof lantern, underfloor heating, bespoke joinery, high-end finishes |
Does an Extension Add Value in Surrey?
Yes. In Surrey, where property prices are high, a well-designed extension consistently adds more in value than it costs to build. A single storey rear extension adding 20 square metres to a Surrey home worth £600,000 can add £60,000 to £120,000 in market value for a build cost of £40,000 to £60,000.
Grand Innovations tip The best return on investment in Surrey extensions comes from open plan kitchen-dining-living extensions at the rear. Buyers in Surrey place significant value on large, light-filled ground floor living space, and a rear extension with good glazing delivers exactly that. |
Hidden Costs to Budget For
- VAT at 20% on labour and materials (some projects qualify for reduced VAT, ask your builder)
- Architect and structural engineer fees: 10% to 15% of build cost
- Planning application fee: £258 for a householder application
- Building regulations fee: £200 to £500
- Party wall surveyor fees if the extension is within 3 metres of a neighbour’s property: £700 to £2,000 per surveyor
- Temporary accommodation if you need to move out during build
- Contingency: always budget 10% to 15% above the quoted figure for unforeseen issues
Frequently Asked Questions
How much does a single storey extension cost in Surrey?
A single storey rear extension in Surrey typically costs between £30,000 and £60,000 for a standard 15 to 25 square metre addition. The exact figure depends on the size, specification, and structural complexity of the project.
How much does a double storey extension cost in Surrey?
A double storey extension in Surrey typically costs between £55,000 and £110,000. While more expensive than a single storey, a two-storey extension adds floor area on both levels, making the cost per square metre lower and the return on investment strong.
Do I need to pay VAT on a house extension?
Yes. Most house extension work is subject to VAT at 20%. Some projects may qualify for a reduced VAT rate, for example if the property has been empty for more than two years. Ask your builder or accountant whether any VAT reliefs apply to your project.
How do I get an accurate quote for a Surrey extension?
The most accurate quotes come after a site visit and a set of architectural drawings. Rough figures based on square meterage give you a starting point, but a proper fixed-price quote requires a full understanding of your site conditions, specification, and any structural requirements. Grand Innovations provides free no-obligation consultations and itemised proposals.
Should I get multiple quotes for an extension?
Yes, two to three quotes is sensible. Make sure each quote covers the same specification and scope of work. A significantly lower quote often means something has been left out or the builder intends to use cheaper materials. Always ask what is and is not included.
Start Your Surrey Extension Project
Grand Innovations has been building high-quality extensions across Surrey for years. We provide free, no-obligation consultations with a clear itemised proposal and no large deposits required.
We cover Surrey, Epsom, Putney, and all surrounding areas.
Request your free cost proposal today and find out exactly what your extension will cost.
