House extensions Costs

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Average House extensions cost

The regular cost of House extensions are £55,929 in your area. Costs vary based upon the materials and the company picked. The upper price range can be as high as £82,929. The material costs are in most cases around£10,500.

Average price per House extensions job in 2025

Avg. price low

Avg. price low
£30,358

Avg. price

Avg. price
£55,929

Avg. price high

Avg. price high
£82,929

£83500

£62625

£41750

£20875

£0

Prices based on actual House extensions costs for your area, as reported by local LeadsDoWork members.

House extensions installation cost in your area 2025

Labour cost £27,000
Material cost £10,500
Waste removal £2,500
Time frame: 10-14 weeks

Advantages for House extensions

  • Create additional usable space within in your home
  • Create more room upstairs, additional bathroom or bedrooms
  • Increases the value of your home
  • As your family grows it means you can stay in the same home for longer

Disadvantages for House extensions

  • Will cause a lot of disruption when the existing house wall is opened up into the extension
  • Upstairs windows should be carefully planned not to look into neighbours homes

House extensions Manufacturers

House extensions FAQs

How big can my house extension be?

The holy grail of home extensions is basically the need for additional space for living as well as leisure. However, before commencing your home extension project, you’d probably want to know just how big your new building can be. In this article, you’ll find the answer to this question which is also frequently asked by many other home or property owners in the UK.

Besides your budget, there are two other major influencing factors that can determine just how much extra room that can be added. These factors include whether you wish to carry out the extension project under Permitted Development rights which is usually for a smaller project or you’d prefer to opt for a larger project which is covered by Planning Permission.

Apart from the limitations in the size of an extension under Permitted Development, the extensions are also a lot more affordable and consumes less time when compared to the extensions under planning permission. So what exactly is the size limit for an extension under Permitted Development and the ones under Planning Permission?

For a single storey extension, the maximum size that can be constructed without having to submit an application for Planning Permission includes:

• An extension should have a maximum length of 6m, if you reside in a terraced home or a semi-detached property.

• Extensions for detached properties can have a maximum length of 8m.

• The extension built must not go beyond half your garden’s area.

• The extension should have a maximum height of 4 metres, but in the event whereby the extension is situated within 2 metres of the boundary of your property, it should not exceed a height of 3 metres.

• The extension should not be higher than the highest part of the existing house’s roof.

What types of extension are there?

There are many different types of extension. For example, you could install an orangery, flat or pitched roof extension, over-structure extension, single or double storey extension or a glass box extension. Which one of these is most suitable will depend on your existing property.

How long do house extensions take?

If you’re about to start your house extension project and wondering how long it’ll take to complete, you’re not alone! This is one of the most common questions that’s asked by homeowners in the UK and across the globe. However, there’s no single precise answer for this as there are multiple factors that’ll affect the length of time it’ll take to complete your home extension. These factors include the size of the construction work as well as whether you’re planning to live in the house after completion or otherwise.

For a single extension, the length of time it’ll take to complete the home extension is normally up to 3 months. So let’s break this down:

As you would have expected, the first step to be taken is the preparation of the site. You start by digging out the footing and preparing the foundation which should take about 2 weeks. This is then followed by the damp course installation as well as the fitting of any drains needed around the extension which will also take a further 2 weeks.

The 5th week will be for the construction of the external walls as well as putting the blockwork in place for the provision of the cavity wall insulation. A further 2 weeks after this, will be dedicated to the installation of the roof structure and the internal walls.

It’s at this junction that you’ll call on your weather proof installer to fit in your uPVC windows and doors. Once done, the gas fitters and electricians will have to be on site to connect power to your new extension building. Subsequently, this will be followed by internal wall plastering as well as breaking through your main house. Once the plaster is dried, decorations completed and all the required furniture and units installed, the extension is ready for use.

Are house extensions worth it?

Often referred to by many as the holy grail of home improvements, house extension comes with a wide range of benefits which makes it easy to see why the extension could be a great uptick in the potential price of your property in terms of sales. So if you’re looking to build a new home extension but still not convinced about the project, we’re here to help you. Being fully aware any home construction work is usually a heavy investment, there’s a huge need to be set on your decision before scheduling the commencement of any work. So are house extensions worth it? Below are some of the top benefits offered by house extensions to help you decide if it’s the most suitable route for you.

• Add To Your Home’s Value

Building an home extension is a great way to add value to your home before selling. Increasing the living space of your home is an incredible appeal to many buyers which significantly increases your property’s total value. However, you must ensure that the extension is impressively designed using top quality materials in order to generate more value.

• Good Alternative To House Moving

The most common reason for moving is usually due to a lack of sufficient space, but with house prices steadily on the increase a cost effective alternative is highly sought after. This alternative is house extension which creates more space for the household to spread out and have more privacy.

• You May Not Require A Planning Permission

You can extend your house and still not need to apply for a planning permission. To achieve this, simply comply with the laid down rules set under the permitted development rights.

• Extra Living Space

If you fill you’re starting to outgrow your existing structure and do not buy into the idea of moving, then your best bet might just be to extend your home.

Where to start with a house extension?

Have you decided to improve your property instead of moving? The common problem most homeowners face after deciding to embark on a home extension project is not knowing where to start. In this article we’ll walk you through everything you need to consider and put in place before commencement of your home extension project.

• Is the extension worth it?

Before breaking the bank, you must be sure that the project will add good value to your home. In terms of “value, this is not only limited to the financial gain after disposal of the property, but also several other juicy benefits to be derived from extending your home like an extra living space for the household to spread out and more.

• Do you need a planning permission?

Check with your local authority to determine whether or not you’ll require to submit an application. You can also consult a building expert like an architect for advice.

• What are the building regulation?

Even though planning permission can be dodged, you can not avoid building regulations. These regulations are the set national minimum standards for construction and design which you must comply with to ensure the safety of the individuals in and around it.

• Who will design the extension?

You have to decided whether you’ll hire a professional architect to design the extension or not.

• Who will manage the building work?

If your home extension project is designed and built by a professional company, they’ll be responsible for the management. However, if you decide to use an architect or designed it yourself, you’ll have to hire a main contractor to manage the build.

• How to set the budget?

There are so many factors that can affect the cost of an extension, so it’s better to get the costs from your builder before proceeding.

• Do I need yo inform my home insurance firm?

Absolutely! This is very important as the new extension may affect the rebuilding cost of your property which could have an impact on the policy premium.

• Do I need to inform my neighbours?

It’s very important to discuss your plan with your neighbours before applying for a planning permission and communicate about the concerns they might have.

When do you need planning permission for a house extension?

If you’re planning on adding a house extension to your property, you’d probably be worried about whether or not your proposed extension would require a planing permission. Well, it may be relieving to know that not every house extension project would require a formal consent, and in fact, several extensions are covered by the permitted development rights. Not only can this save you a considerable amount of time especially at the project’s planning phase, but it’ll also save you money on the application fee. In the UK, single storey extensions to the house’s rear can be 3 metres deep for both semi detached houses and terraces or 8 metres deep for detached homes.

So how do you know when you’d require a planning permission for your home extension? Well, if your extension plan fits these criteria explained below, then your project is most likely going to be allowable as a permitted development.

• Extensions, which includes previous additions, must not go beyond half of the original house’s total surrounding land area.

• The main elevation, or side elevation where it fronts the highway, must not be extended forward.

• For single storeys, the rear additions must not extend more than the original house’s rear by more than 3 metres in both semi attached homes and terraces (4 metres for detached houses).

• Extensions to the side must be a single storey with a height not exceeding 4 metres and not going beyond 50% of the original house’s width.

• Extensions hat within 2 metres of a boundary should have a eaves height not more than 3 metres.

• Multi storey addition must not extend beyond the original house’s rear wall by a maximum of 3 metres or 7 metres of the boundary opposite the rear wall.

• Permitted development rights do not apply in listed buildings or designated areas.

How much value does an extension add to your house?

Are you interested in extending your home to create more living space? If yes, then you’d probably want to know how much value it can add to your property in order to compare the building costs to the potential value gain. Well, as long as you know what you’re doing, your house doesn’t necessarily have to be a money pit. So what are your options when talking about home extensions and what’s the associated value to be gained?

• Bathroom Extensions

Although you should have it in mind that bathroom extensions isn’t usually that cheap, but once done, it can increase the value of a standard UK house within the range of £12,000 to £15,000. Meanwhile the finishing cost of a bathroom can range from £2,500 to £7,000.

• Single or Double Storey Extensions

Single storey extensions are always huge when it comes to increasing the value of your home - giving about 4 to 7 percent increase. If it goes that far, then literally nothing beats a full spectrum, double storey extension which can give up to 11 percent increase in the value of a property - equalling about a whooping £33,000 for a standard home in the UK.

• Conservatory Extension

With conservatories becoming more and more popular in the UK due to the weather conditions, several buyers are now including it’s availability as part of the criteria for purchasing a house. Wonder why? This is simply because everyone wants to enjoy their garden all throughout the year. As a result of this high demand, adding this type of extension to your house can go a long way to increase it’s value. However, it’s very important to incorporate high quality materials during construction. With glass conservatories offering, on the average, up to £5,000 increase in value, the cheaper PVC alternative offers much less value and can also deter potential buyers.

Can I extend the front of my house?

When it comes to extending a home, the rear of the house often comes to mind a lot more than the front. However, this doesn’t mean that you can’t extend the front of your house. This can be done either as part of a renovation project whereby the entire house is incorporated or it can also be done in isolation. It’s possible to extend the front of your house without the need to apply for a planning permission, however, there are a bunch of limitations you’d have to comply with if you wish to carry out with such a project. Sometimes, this may imply that extending to the front of your home is more tedious and tasking than extending your home’s rear. So exactly how far can you extend the front of your home without planning permission?

 

The short and simple answer to this question is 2 metres square area with a height not more than 3 metres. Generally, you do not need a planning permission to build a front porch as long as its area doesn’t go beyond 2 square metres from a public road or walkway. Also, a tiled or slated roof can be as much as 4 metres but other roofs must not go beyond 3 metres in height. If you want to extend the front of your home beyond the restrictions specified, then you’ll have to apply for a planning permission.

 

Extending the front of home can be quite costly, but this can be controlled by not building to the extension to the highest specification, not including an extension on kitchens or bathrooms and more.

PROJECT ADVICE | 10 ways to cut the cost of your extension | Future Homes Network

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