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 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.

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.

Will my extension be expensive?

It depends on the size and type of extension. Small porches or flat roof extensions are very reasonably priced. More substantial two storey extensions can be expensive. In general, the price is roughly proportional to the amount of space you add to your home.

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.

Do I need my neighbours’ permission for an extension?

Well the reality is, sometimes, neighbours just don’t get along. With several individuals living in close proximity, it’s little surprise they tend to get on one another’s nerves from time to time. However, there’s a difference between having a tiff and being able to transform your house the way you want without having to obtain your neighbour’s approval.

The short and simple answer to this question is, not necessarily. However, you must first educate yourself by thinking about your extension and how it affects the houses around you. We’d strongly recommend you talk proposals through with your neighbour so as to avoid possible conflicts later. There are a number of reasons why your neighbour can protest to your new home extension plans. Let’s take a look!

 

  • In the event whereby your new extension is blocking their view or providing an unwanted shade on their property. Here, they have a legitimate reason to protest as no one would want their once sunny garden suddenly covered or plummet into shade.
  • In the event where it leads to a loss of privacy. For instance, if your new extension possesses a window which overlooks the neighbour’s property in any way. This is likely to be taken as an invasion of privacy and that has a little to no chance of being a welcomed idea.
  • If it’s a major project and going to take a lot of weeks before completion. The noise generated, especially when your neighbours are enjoying your summer holidays or weekends, can make their gardens not as relaxing as it used to be.
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.

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 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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