How much does an extension add to the value of a house?

House extensions are an extremely popular way to add living space to the home you love – from expanding your kitchen with a single-storey extension or building a full two-storey extension. The important question to ask when carrying out any major home improvement project is – how much does an extension add to the value of a house?

You might not be building the extension to sell your house immediately – and often quite the opposite is true. Most homeowners extend their properties in order not to sell. And a house extension will almost always add value to your home.

That said, it’s important to understand how much value a possible extension would add to your house so that you know what a sensible budget will be for the project.

How much value does an extension add?

The amount of value that an extension will add to a property’s value will vary considerably, depending on the size, style and complexity of the extension, not to mention the location of the property.

In the UK, an average 3-bedroom house with an extension that creates a double bedroom with an en-suite bathroom can add up to 10-12% to the value of the property.

It’s important to do your homework to understand how the design of your extension will impact the value it adds to your home. Adding double bedrooms and bathrooms tend to add the most value.

In order to get an accurate evaluation of how much value your extension could add, speak to local property experts and architects for their professional advice. You’ll want to find out the current market value of your home, as well as its potential value once the changes have been made – based on your plans.

Best extensions to add value to your home

If one of the main goals for your house extension is to add as much value to your home as possible, here are some of the most valuable house extensions and conversion you can do:

Loft conversion – average value add: up to 20%

Extremely popular due to it being one of the most affordable ways to create more living space for your home. Typically used to add an extra bedroom, often with an en-suite bathroom, a loft conversion can add around 20% to the value of your house.

Single-storey extension – average value add: 5-8%

Single-storey extensions are most commonly used to extend kitchens and/or living rooms to increase the overall amount of general living space. With open plan living being hugely popular with homeowners in the UK, single-storey extensions are a popular choice and can often add 5 – 8% to the value of your home.

Double-storey extension – average value add: up to 12%

If you decide to go for a full double-storey extension, you’ll most likely be increasing general living space and adding bedrooms and bathrooms, which are ideal for adding value to the property. It’s estimated that a double-storey extension can add up to about 12%.

Conservatory – average value add: 5-7%

For homeowners with limited budgets looking to extend the living space in their home, a conservatory is a common option. With average conservatory costs starting around £9,500, it’s a more affordable way to gain space and add between 5-7% to the value of your home.

Garage conversion – average value add: 10-20%

A garage conversion is one of the most potentially valuable home improvement projects you can do. With most garages in the UK not actually being used as garages, it’s no surprise that many homeowners are converting them into useful (and valuable) living spaces. A garage conversion that creates a bedroom with an en-suite bathroom could add up to a whopping 20% to the value of your home. If you convert the garage to a study, playroom or home gym the value add is around 10%.

Things to consider to add value with an extension

To make sure your house extension doesn’t end up costing way more than the value it adds to your home, here are a few important points to consider:

• Check the ceiling price for similar properties in your neighbourhood (and don’t expect buyers to pay above that).
• Compare the budget to the value add and make sure the estimated cost of the extension is lower than the potential added value.
• Consider any complexities such as sloping ground or deeper foundations that could make the extension more expensive.
• Quality costs more but will add more value, so make sure you hire experienced, qualified tradespeople to carry out the extension work to a high standard.

How much does an extension cost?

As previously mentioned, the total cost of a house extension will depend on a number of factors including the size, style and design of the extensions itself, the location of your property and the quality of the fixtures and finishes.

As a guide, you can expect to pay the following costs for a house extension in the UK:

• Small extension (20m2) – £25,000 – £50,000
• Medium extension (30m2) – £37,500 – £67,500
• Large extension (50m2) – £62,500 – £112,500
• Premium extension (30m2) – £52,500 – £100,000

To find out more about prices, take a look at our guides on house extension costs, two storey extension costs and SIPS extension costs.

How much does a single-storey extension add to the value of a house?

For a standard single-storey extension, you can expect to add around 5-8% to the value of your house. Obviously, this will depend on the size, style and exact design of the extension.

What adds more value, an extension or conservatory?

It depends on the size and style of extension or conservatory, but in general, an extension will add more value to your property than a conservatory – particularly if the extension adds any bedrooms and bathrooms.