Extensions – A Look at Per Square Metre Pricing in the UK

The current climate in the housing market isn’t ideal for house movers. Price rises have levelled off, stamp duty is at an all-time high, and there’s considerable economic uncertainty within the UK.

The good news is that the government has made it easier for homeowners to extend their existing properties. Some of the most popular house extensions do not even require a planning application – if your build is within strict conditions.

Five Reasons to Extend Rather Than Relocate

Here are five reasons we think you should extend rather than move to a new home:

  • You pay stamp duty when you buy a property and the average sum paid is over £2000.
  • The average amount paid in estate agent fees is over £2500.
  • Mortage set up fees, also known as product fees, average around £1000.
  • Legal fees, conveyancing, house surveys and moving costs can set you back over £1500 when buying a home at an average price.
  • Save your money and spend it on an extension and you’ll potentially get much more back when you come to sell the property in the future when the market improves.

But how much does it cost to extend a home, which s the cheapest option and which one will maximise your investment?

Garage conversion

Extension Costs – A Look at Prices

Below you’ll find our guide to extension costs in the UK.

All of the prices displayed below are per square metre of internal floor space and were last updated in 2018.

We’ve got guideline prices for the construction of:

  • Loft extensions.
  • Garage conversions.
  • Single storey extensions.
  • Double storey extensions.
  • Basement extensions.
  • Conservatories and orangeries.

Loft Extensions

A loft conversion is one of the least disruptive types of extension you can build.

Almost all of the work can be completed from the scaffold and within the loft, with minimal disruption to those living in the house.

Because the primary structure of the loft is already constructed, there’s very little structural work, apart from some floor strengthening and a dormer, if you choose to have one.

A very basic loft conversion comprising of just one double room and excluding any fitting out fees can cost less than £900 per square metre.

Add in an en-suite, and some premium finishes such as floor tiles, carpets, blinds, a power shower etc. and the price can quickly reach £1100 per square metre.

If you’re considering a conversion, check out this detailed loft extension price guide.

Garage Conversions

There are two types of garage conversion worth considering; integrated and attached garages.

Integrated garages are the cheapest to convert; the walls are often constructed to the desired specification, and the garage only needs some minor structural changes such as replacing the door with a wall and window.

Attached garages may require additional blockwork, insulation and also changes to the roof design if it has a flat roof.

A basic single garage conversion, perhaps to create a separate room will cost in the region of £700 per square metre.

Add in some remodelling of the existing home, perhaps to extend a kitchen and create an open plan space, and you’ll be looking at just over £1000 per square metre of floor space.

This page contains an in-depth look at garage conversion prices in the UK.

Single Storey Extensions

Single storey extensions are often constructed to extend living rooms, kitchens and to create kitchen diners. The remodelling and fitting out of these extensions can bump up the price.

A straight-forward single-storey extension to create a separate room such as a study or bedroom will cost from £1200 per square metre.

Extend a kitchen, construct a kitchen diner or create an open-plan living space and the prices often exceed £1700 per square metre, this assumes a medium quality spec.

Double Storey Extensions

A double storey extension uses the same foundation footprint as a single storey extension, so there’s no need for additional costly excavation work.

A realistic starting price for a basic double storey extension is £1100 per square metre.

Add in a bathroom, a remodelled kitchen, some open plan living space or a higher quality spec and the cost will be closer to £1500 per square metre.

This page contains a helpful guide to house extension prices in the UK.

Basement Extensions

Basement extensions are by far the most expensive option and can cost up to three times as much as a single storey project.

This type of extension is very popular in areas where land price is at a premium such as in London.

A recent article in the Evening Standard claimed that in some parts of Kensington and Chelsea, the cost per square metre of floor space in some properties exceeds £19,000.

When taken in this context, a basement extension with a price tag of between £3000 and £4000 per square metre looks much more attractive.

Conservatories and Orangeries

The cost of a conservatory varies and depends on size, design and whether you want glass or would accept polycarbonate plastic panels.

We know from our research that the average cost of a pre-fabricated conservatory is around £10,000.

Orangeries are usually more practical than a conservatory, they blend in better with the existing property but can cost more than a single-storey extension.

See how much an orangery costs per square metre on this page.

What Have We Excluded From These Prices?

We have excluded VAT from the prices we’ve published on this page. Many builders and tradespeople run small businesses that operate below the VAT registration threshold so they wouldn’t charge you this tax on their labour.

Architect fees can range from 5% to 14% of the total build price, how much you’ll pay depends on the complexity of the project and how involved you want the architect to be. We’ve excluded these costs from our price guide.

Not every project requires the services of an architect if you’re using an experienced project manager and the build is straightforward and simple.

Keep a Lid on Costs

To achieve a return on your investment, you’ll need to keep a lid on expenditure and only extend when it’s likely to increase the house value.

In many areas of the UK, the price of a four-bed home is almost the same as a five-bed home, so you probably won’t get a good return on your investment.

As a general rule of thumb, the best homes to extend are one, two and three-bed properties

Did you know that not every house extension project requires planning permission?

Planning permission requires full detailed drawing plans, is costly, takes time to come through and your local council may reject it.

You can construct some loft and garage conversions and also many extensions without planning permission.

This page contains an insightful guide to six home improvements and extensions you can build without planning permission.

Get a Quote

If you would like a detailed quote to extend your property, tap the button below to see how we can help you:

  • Send in details of your extension project.
  • Get a written quote promptly.
  • Read impartial reviews created by past customers.
  • Leave your feedback when the project is complete.
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