House extensions Costs

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Average House extensions cost

The regular cost of House extensions are £54,563 in your area. Costs vary based upon the materials and the company picked. The upper price range can be as high as £80,063. The material costs are in most cases around£10,500.

Average price per House extensions job in 2026

Avg. price low

Avg. price low
£30,313

Avg. price

Avg. price
£54,563

Avg. price high

Avg. price high
£80,063

£80600

£60450

£40300

£20150

£0

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

House extensions installation cost in your area 2026

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

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.

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.

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 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.

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.

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.

How much does a two storey house extension cost?

If you’re considering adding a two storey house extension, then setting a budget for this project would be a great way to get started. Similar to a rear extension, a two storey extension usually leaves the rest of the building needing some work and, due to its size, this may imply the re-development of the entire house - which is why they can be very costly. Some of the other influencing factors that can have big impact on a two storey house extension cost includes: your location, the size of the build, complexity of the design ( anything beyond the standard build will normally require more expertise and time), the glazing to be incorporated ( the more the glass used in the project, the more the material cost), as well as the team used.

Generally, when it comes to extensions, the major part of the expenses will be made on the build of the project. This is because it doesn’t only cover the material cost but also the contractor’s overhead as well as the daily rates. At this stage, the extension prices can be determined by the standard of the work that’s being done.

For a fairly average room size of about 18 square metre, the two storey extension should cost within the range of £2,500 to £3,000 per square metre - with the range being determined by the finishes incorporated. Therefore, a two storey extension of about 18 square metre should cost within the range of £45,000 to £55,000. However, this is with the assumption that there are standard window sizes, bathroom suits are modest, and without any need for any purpose joinery or glazing. If you wish to include all these extra features you’ll also have to pay more to make the total cost between £70,000 to £80,000.

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