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

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 to finance a house extension?

Do you want to beautify and increase the value of your home? If yes, a refurb and house extension is definitely a great option to consider. Depending on your home extension project, the value that’ll be added to your home’s resale value varies. However, the cost of completing a house extension project can be huge, so you just might want to consider your financing options. Fortunately, there are various options through which your house extension project can be funded with each having its own pros and cons. Your specific circumstances will determine the one that’s going to work best for you, so let’s take a look at some of the best options to help you fund your project.

• Home Remortgaging

The process whereby a mortgage is transferred from one provider to the other is known as remortgaging. This is usually done to generate funds for a project by entering a more lengthy repayment term commitment when switching. If you want to raise your funds in a quick manner, this process works best.

• Savings

This is a good reason to cultivate a good saving habits. If you’ve been able to save up some mega bucks then you’d probably won’t have to borrow money to finance your house extension.

• Unsecured Loans

If you do not buy into the idea of borrowing more against your property, you may just be able to apply for an unsecured loan especially if you have a good credit record. A secured loan makes use of collaterals like a car or house to serve as a cover for the lender, meanwhile an unsecured loan is based mainly on the credit managing history of the borrower.

• Credit Card

There are some great benefits that comes with financing your small or medium scale extension project with your credit card. Not only does it offer some real lifeline if problems arise during the project, but you can also avoid paying excessive interest on the investment by ensuring your deal has a 0% introductory rate.

Should I use concrete or timber footings?

For 2 metre solid fences it’s recommended to use concrete posts to support each panel. For smaller 1 metre fences or for picket fences with gaps between each timber piece you can use timber posts. A fencing contractor will be able to advise you on the best materials from the length and requirements of a new fence.

Can an extension add value to my home?

Yes. Most extensions will add substantial value to your home, and you may find that the extension adds more value than it cost. However, it’s important to be sure that the home remains balanced. Extending your garage and leaving your property with no parking spaces, for example, may impact your ability to sell.

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.

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 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.

How much is a double house extension?

A double house extension is basically a construction to any aspect of your house that elevates up to offer two floors of space. It can be structured to suit your existing home in two storeys or as a side wing on a taller property. If you’re considering building a double house extension, then estimating the cost is a very important task to do before commencing the project. In this article, we’ll give you an idea of the cost of a double house extension so you can estimate yours accordingly.

The double house extension cost depends on several factors that’s specific to your home as well as your design choice. These includes:

• Location of your property. Places like London and the southeast will generally cost more than the other regions due to higher demands.

• Accessibility of the site. The ease of your site’s accessibility also plays a key role in the price.

• Size of the extension. The more the extension’s size in footprint and square metres, the higher the possible costs.

• Materials used in making the roof as well as the complexity of the roof design.

• Your choice of finishing. These includes flooring window and door frames, glazing, underfloor heating and roof lights.

• Your property’s soil type. Different types of soil requires varying treatments as well as materials to develop solid foundations.

Constructing a double house extension is a quite simple build in terms of technicality when its to the side or rear of your house as this can also help you save some money. Generally, considerably expanding your home’s space by building a double house extension will cost within the range of £1,500 per m2 to about £2,800 per m2.

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