How Much Does a House Extension Cost?

How much do house extensions cost in the UK?

If your desire for more space has led you to ask, ‘How much does an extension cost?’ we can provide some pointers.

The baseline you are probably looking for is the average cost of making your living space larger by building into your garden space.

Certainly, making your existing structure larger will form the basis of your extension costs, but the equation can be complicated with both costs and benefits to consider.

The benefits of a house extension

Positive impact on family life

A single-story extension could give you useful space for an office or playroom, making your current living space less cluttered and creating a calmer environment.

A rear extension to make your kitchen bigger could bring the whole family together in a more usable dining and living space.

It can be hard to weigh the value of more space in terms of its positive impact on family life against the extension cost, but the effect of a better living space can be significant.

You can avoid moving for longer

A house extension may help you save money by giving you the space you need in your current house.

The emotional toll exacted by the disruption of moving home is well known. The monetary cost of increased mortgage payments, mortgage arrangement costs and removal expenses can be daunting. Why not stay put and create more space in your current property?

Increases the value of your property

It is hard to say exactly how much a good extension will add to the value of your house, but it could be in the region of 10%.

However, when you do decide to sell, you could certainly recoup your extension cost.


How to price a brick house extension

There is an equation that can be used to answer the question of how much it costs to build a traditional brick-and-mortar extension.

Builders use a cost per square metre figure to estimate how much your house extension will cost. This can be applied, whatever the size of your existing structure and the size of the new extension. At the time of writing, the average cost per square metre is £1,800 – £3,000 per square metre.

What is the average cost of a brick-built house extension?

House extension costs vary according to the size of the space created.

At current prices, the construction cost of a single-storey extension starts at around £40,000. Obviously, a double-storey extension or a large wrap-around extension will cost more.


Potential additional house extension costs

The price per square metre that your builder may not include several additional costs that will increase the overall cost of an extension.

Planning permission

Unless the size of your extension is within permitted development rights, you may have to apply for planning permission. Submitting a planning application for consideration by your local authority planning office could cost in the region of £200.

Technical drawings

Depending on the complexity of your design, you may need a qualified person to draw up detailed drawings of your extension plans.

Hiring a structural engineer

Once work has been started, unexpected issues with your existing property may be revealed, which may require the services of a structural engineer.

Party wall agreement

If you are planning a semi-detached house extension, you will need to be aware of the Party Wall Act 1996. This can be an issue when a double-storey extension is being built. You may need to pay for a party wall survey and a party wall agreement with your neighbour.

Fixtures and fittings

Your builder’s estimate may cover just the shell of your extension. You will have to add on plumbing and electrical costs plus new units and appliances for a kitchen extension.



Why are house extensions so expensive?

House extension costs are affected by rises in inflation as much as other living costs.

Increased building material costs and labour costs have made house building more expensive.

Does a SIP house extension cost less?

We provide a quality product at a fair price, but there is one factor that makes our extension projects great value for money – the speed at which we can build your house extension.

Construction using the traditional method is highly labour-intensive, and the extension project can take months to complete. Our SIP extensions can be constructed in weeks meaning that labour costs are considerably less.

How much do SIP house extensions cost?

We do things differently at PCL. If you put the dimensions that you would like into our quick quotes form here, we can give you a price estimate for an extension constructed from our SIP panels.

If you need any more pricing advice, you can call our friendly team on 0161 300 4900.

Why are SIP house extensions different from traditional methods?

In fact, structurally insulated panels or SIPS are a mainstream material in other countries, including the USA, Japan and Scandinavia and have been widely used since the 1950s.

The panels are constructed from two structural facings put together with a filling of liquid foam. They can be factory-made to fit most building designs and then assembled on-site.

SIP Panels are stronger than brick and timber structures and have excellent insulation qualities saving you money on heating.

What sort of house extension can be built with SIP Panels?

If you’re considering a single-storey house extension then SIPS could be ideal for your project.

We have experience in building a variety of extensions including conservatories, full single-storey ground-floor extensions, garage conversions, annexes and ground-floor wet rooms and washrooms.

You can find some more house extension ideas on our website here where you will find details of all our building products and services.

Next steps

Why not find out more about PCL extensions by browsing our website or chatting with our friendly team by phoning 0161 300 4900?


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