How much value does an extension add and which type could reap the biggest reward?

If the feeling you're outgrowing your home has led you to consider extension ideas, it's only natural to wonder how much value does an extension add – even if you're not planning on moving again anytime soon.

Or perhaps you've purchased a home with a view to renovating and extending, in which case although getting a return on your investment will be emotionally tangible immediately, knowing what you might get back in cash terms in the future is important to help finalise your budget, as any costs spent will need to be recouped.

But, it's not just about the monetary value, there are other benefits too. We asked property experts for their views on how much value does an extension add and which type will give you the best return both now, and when it comes to selling your home.

How does an extension add value?

Before we delve into the monetary benefits of adding an extension, it's worth looking at the additional value one adds to your home as a whole, says Natalie Mitchell, property and construction expert at HomeHow.

In general, whether you're looking to add a kitchen extension, utility or bedroom, each extension will add value to your lived experience in the following ways:

1. Increased living space

"Extending your home means that you will have more room and living space for yourself and your family. Instead of living in cramped and cluttered conditions, you will now have plenty of space for your needs," says Natalie. "It will allow your home to become more comfortable, functional and give you the freedom to use that space as best befits your family's needs."

2. Added storage space

"Along with extra living space, an extension can be a great opportunity to add more storage space to your home. You will be able to add new cupboards, shelves and closets to your home, freeing up space in other rooms," advises Natalie. "You may also wish to use the extra space entirely for storage, it comes with a lot of freedom and reduces the worry over where to put everything and how to keep your home looking clutter-free."

3. Alternative to moving

"If upsizing feels a little out of reach, and you're not sure whether to move or extend, adding an extension can be the ideal solution to avoiding the cost and stress that comes with moving home. You can stay in the home that you love and simply adapt it to meet your changing needs," she suggests. "By adding an extension, you will also be avoiding a lot of the costs that add up when moving to a brand new home, such as estate agent fees, stamp duty, and removal costs."

4. A bespoke living space

"Unlike buying a new home, adding an extension to your current home allows you to have full control over the design and functionality of the new space. Every aspect can be tailored to look, and function, exactly how you want it to," says Natalie.

Types of extension and their added monetary value

“Adding space is a great way to boost the value of your home, both for you, and future owners," says Colby Short, co-founder and CEO of Get Agent, "but it’s important to understand which areas of the house add the most value in the eyes of buyers, before you commit to improving or expanding them."

And although your need for more space means you may not be able to consider a loft conversion as part of your extension plans, when it comes to extension vs loft conversion, there's one clear winner say the experts.

"A loft conversion is likely to bring about the biggest boost, as it’s thought to add 20% to the value of your home - that’s over £50,000 on the current average UK house price," says Colby.

But why is this type of extension the one that adds the most value?

"It's largely down to the potential and versatility of the space, as not only will it add a considerable extension to your home without the need to start completely from scratch, it can be used for a variety of uses," explains Colby. As well as providing a great space for a new master bedroom and ensuite, it can also serve as, "a home office, an additional guest bedroom, a nursery, play room and so on," he adds.

However, if you're looking for extra kitchen or living space, loft conversion ideas won't always be suitable. So what is your next best option?

"Double storey extensions, along with kitchen and garage conversions are also some of the best to tackle if adding value is your aim, as they will bring a boost of between 10% to 12%," says Marc von Grundherr, Director of Benham & Reeves.

Suitable for adding extra living space as well as bedrooms or home office solutions, the cost of a double storey extension also isn't twice as much as a single storey, meaning as well as giving you and your family more space while you live there, it could potentially widen your buyer market if you've added bedrooms and opportunities for separate reception areas.

"However, whilst double storey conversions bring some of the biggest value boosts, if speed matters at this moment in time, single storey extensions will cost less and can be completed more quickly," adds Marc.

That said, choosing the right kind of single storey extension matters too according to Colby Short, who breaks down the potential cost vs value gained for some of the most popular types of extension when compared against the average house price in the UK.

Of course, what these figures don't account for is the average cost of an extension which can vary greatly depending on the type, size and style you add, as well as the added value of any other renovations that take place as the same time as adding an extension.

And, while the average house price is used for the purpose of this table, these often tend to be smaller properties where there isn't room to extend in any direction. The reality is you will likely have paid more than this for your property.

So while you may look at the average cost of a kitchen extension and see figures of £50,000 plus and see a value add of £53,617, if you are buying a lower cost property as a renovation project, remember the overall value of it won't just increase by the 20% your kitchen extension has added.

Colby Short

Colby is one of the co-founders of GetAgent.co.uk, a platform that utilises whole of market data to provide cutting edge data and statistics on estate agency performance, from the time it takes to sell in each area of the nation, to the percentage of asking price achieved.

Marc von Grundherr

Marc is Director at Benham & Reeves, one of London’s largest lettings and sales estate agents, with 21 branches across the capital, as well as 12 international offices. Marc joined the business in 1995 and has an extensive knowledge of both the London and wider UK markets, not only as an industry expert and spokesperson, but also as an investor and buy-to-let landlord.

How to get the best value when adding an extension

So what do the experts suggest when it comes to making sure you get the best value out of any extension you add to your home? The good news is that any extension, done well, will add some type of value, but it's getting the execution of it right that can have the greatest impact.

"When it comes to reducing property value, an extension, if done properly, is rarely ever going to reduce your house price," says Colby Short. "So, whilst there’s no real bad extension in this respect, a poorly executed project however could potentially reduce the value of your home.

"Poor designs, overly large additions, extensions that alter the original character or a house, or poor materials could all contribute to a poor extension that could do more harm than good," he warns.

If you do have plans to extend in order to boost your property’s appeal during the selling process, both now, or in the future there are always steps you can take to ensure you execute the project properly and protect yourself when it comes to moving on. Marc von Grundherr suggests the following four key areas are covered correctly:

"1. Understand what planning permission or building regulations might impact your extension and consult with your neighbours to fully understand any party wall agreements.

2. A detailed survey and a good structural engineer, as well as a top notch architect and builder are all vital pieces to the puzzle.

3. Plan your budget meticulously and don’t over stretch, such projects rarely go to plan and will always need a contingency pot for any unforeseen costs.

4. Don’t be overly ambitious and implement an extension that is keeping with the original property and won’t detract from the overall aesthetic appeal of the property.”

Keen to forge ahead but concerned you may not have enough space to extend, find inspiration in these small house extension ideas or if it's your kitchen you're considering extending, find out if a kitchen remodel could create the space you need without needing any kind of extension at all.