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House Extension Cost Calculator

How much does an extension cost?

Our home extension cost calculator is a purpose-built tool, designed to provide you with a realistic estimate of your personal house extension costs.

Our team is based in the North West, so whether you want to find out the cost of house extensions in Manchester centre and Greater Manchester, or you live further out and are trying to research Cheshire home extension prices, our calculator is the ideal place to start.

If you want to work out the cost of an extension on your property, use our calculator to generate your personalised quote now. Or, call us directly on 01625 885 030 to arrange a consultation with one of our specialists and to find out more about house extensions in the North West.

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FAQs below, click to

How much does it cost to build an extension in the North West?

If you are hoping to create some extra space by undergoing an extension project, there are several factors you need to consider if you want to calculate costs.

For example, you must factor in planning, engineering and labour costs, as well as the cost of materials.

When trying to calculate your house extension costs, you should consider the following areas:

  1. Planning and design costs. You may choose to have an architect design your home’s extension. Or you may need one to assess the structural integrity of your house before you are able to begin your extension project.
  2. The intended size of the extension. Generally, initial extension building costs are calculated based on your property’s size and are worked out by multiplying the square footage by labour rates. This is often referred to as the ‘cost per m2’.
  3. The number of storeys in your house. Whether your house is 1 or 2 storeys will have a bearing on how costly your house extension will be. 2 storey house extension costs are generally about 50% more expensive.
  4. The materials you want to use. This makes a huge difference to the final cost of an extension. The type of brick or building block you want to use in the construction stages will affect final extension prices. When it comes to cladding, stone is a more expensive choice than brick and your choice of finishing materials, like tiles or wood panels, also impacts costs.
  5. Steelwork costs. If you need steelwork for your house extension, this will increase the expense of the project. A structural engineer will need to evaluate the type and amount of steelwork involved in extending your home. Steelwork cost estimates usually suggest between £20 and £35 per square metre of steel.
  6. Your time constraints and deadlines. The length of your extension project also need to be taken into consideration when trying to work out the costs of extending a house. If you have a date in mind for when you want the build to be completed, for instance, you will need to pay more money in faster delivery fees and longer labour hours.

The total cost of an extension project must be worked out carefully before you start work on extending your home. This is to ensure that you have the appropriate budget for the job.

How much do house extensions in Manchester cost?

If you are a homeowner in the North West and you’re hoping to extend your home, you might be searching for how much house extensions in Manchester cost.

While the average cost of a Manchester home extension varies (as this depends on factors like the size of your property, the materials used and the type of extension you’re undergoing) the rough house extension price in Manchester is between £1,200-£2,000 per square metre.

House extension costs are cheaper in the North West than in other parts of the UK, for several reasons. Firstly, property prices are higher in places like London and the South, which impacts the total house extension costs. Secondly, architect and builder fees tend to be lower in the North of England, which also impacts your final costs. Typically, Manchester house extension architects fees are around 8% of the total project cost, though this does vary.

Whether you’re looking to extend your Stockport home, or you are looking for Cheshire extension services, our calculator is a great place to start. It is designed to take into account all your circumstances, including your location. It then generates a realistic estimate of the total costs of your house extension in the North West and provides you with a bespoke quote.

What are the different stages of an extension project?

There are several different stages of a house extension. Each stage has its own set of costs involved, so you should make sure you budget for each one when planning.

Stage 1: Planning permission and design

You may wish/need an architect or architectural designer to visit your house before you can begin your extension. This may be to assist with planning and designing an extension, or it could be to assess the viability of your current plans. This stage can increase the costs of extending a house. Architectural drawings usually come in at around £500 - £1,000.

You may also need to get planning permission if you want to undergo an extension project. This will need to be given by a local authority, like a council and can cost up to £200. Depending on how much building control you have, you may also need neighbourhood permission for your plans.

Stage 2: Laying the groundwork

The costs of groundworks are something else to factor into costing an extension. Prices can vary at this stage, and extending your house can become more expensive if more groundworks need to be done. For example, if drains need refitting, this costs more. Soil type can also impact the cost.

Stage 3: Constructing the building’s shell

At this stage -- where construction of the building actually takes place -- the main extension costs calculated are to do with the size of your home. Build costs are normally generated by multiplying the size of the home by the price of the building work. Construction materials are, according to specialists, roughly the same. So, if you are building a shell with a timber frame, bricks, or blocks, the cost works out as roughly the same per square metre.

Stage 4: Adding fittings

Fittings might include plug sockets, bathroom fixtures, skirting boards or any other essential or non-essential feature you want in your extension. Depending on what you intend to use the extra space for, this stage can greatly increase the overall costs of an extension in the UK.

Stage 5: Finishing touches

Finishishing touches can make the overall house extension price soar. They also vary drastically, and they come down to what you want your final space to look like and do. You may wish to have a simple carpet on the floor, or you may want to install imported marble tiles, for example. If you are including a bathroom extension in your new living space, the average finishing costs for this are approximately £3,000 and £10,000. The kitchen extension costs are between around £7,000 and £26,000.

How much does an extension cost in a small house?

A small house extension cost is usually less than that for a bigger house. If you are extending a single storey house, this is significantly cheaper than a 2 storey extension.

Generally, house extension costs are calculated based on the size of the house -- and then extra costs can be incurred depending on factors like the materials you use and finishes. Most estimates multiply floor space and the height (metres squared) by build costs.

If you’re trying to work out the small house extension costs, you can use our home extension cost calculator. This will generate a realistic estimate based on the size of your home, your requirements, and other key factors.

How much does a 2 storey extension cost in the North West?

A double-storey extension costs around 50% - 75% more than a single storey extension. This estimate is based on both storeys in the house being roughly the same size.

Additional costs must be added if you intend for certain facilities to be added into your extension project plans. For example, you must budget more if you would like to have a kitchen or a bathroom added. As a general rule of thumb, two storey extensions cost more than single storeys and smaller houses.

How much would a front extension in Manchester cost?

The average cost of a front extension in the North West is approximately £1,200-£1,500 per square metre. However, these costs can vary greatly depending on different factors. For example, a house extension in Altrincham may cost more than home extensions in Bolton because the property prices are higher in this area.

Likewise, Manchester house extension architects can vary greatly. They tend to be around 8% of the total build cost, but this can move up to 12% depending on the agency you choose to work with, and the complexity of the project.

What is the average cost of a Manchester bedroom extension?

House extensions in the North West, including in Manchester, cost different amounts depending on the type of project you are undergoing.

The average cost for a Manchester bedroom extension is between £16,000 and £70,000 if they are on one floor. Bedroom extensions in Manchester and the rest of the UK are calculated per square metre, so the bigger your bedroom the more it will cost.

If your bedroom is upstairs, you might need to undergo a two-storey extension to be able to make the space you want. Two-storey extensions add between 50 and-75% of the cost of a single-storey extension to the final bedroom extension cost. In that case, the cost of a Manchester bedroom extension would be between £24,000 and £100,000.

How much does a 50m2 extension cost?

A 50m2 extension is on the larger end of the scale when it comes to home extensions. The general costs of any extension, including a 50m2 one, can be worked out by looking at the square footage (in this case 50 square metres) of the property, and multiplying it by the cost of labour and materials.

Estimates for a 50m2 house extension vary drastically. This is because final costs depend on the quality of materials used, and the intention of the extra space (for example, will a kitchen or bathroom be built?).

Generally, a 50m2 extension costs between £55,000 - £150,000.

If you are looking into extending your property and you want to know how the size will impact the final prices and fees, use our extension cost calculator. This will provide you with a more specific estimate based on the different costing factors of extending a 50m2 (or other size) space.

Does the location of my property impact the final house extension costs?

As homeowners, there are other factors you must consider when trying to calculate the price of a home extension. Location is one of them. UK extension costs are higher in certain areas of the country. This is for a number of reasons. Firstly that property prices are different across the country. In the South, they are (generally) higher than in the North, though there are pockets of Northern England where they reach similar levels.

You also need to factor in building regulations and planning permission. These can be harder to navigate and acquire in major cities, making overall costs higher.

The cost of extending your property is highest in London. Outside of the capital and its outskirts, the average extension price per m2 is between £1,200 and £1,500. However, the estimated house extension costs in London and the South-East of England are between £1,500 and £2,500.

Our team works exclusively in the North West. We have helped build extensions in and around Greater Manchester as well as other parts of the North West.

Our range North West house extension services include:

  • House extensions in Stockport (including Bramhall, Cheadle Hulme, Hazel Grove and Marple)
  • Didsbury home extensions (and other parts of South Manchester, including Withington, Chorlton and Fallowfield)
  • Altrincham house extensions and conversions
  • Cheshire home extensions (including Alderley Edge house extensions and conversions)

If you are a homeowner in any of these (or surrounding) areas, use our extension cost calculator to find out how much a house extension in Manchester and the North West will cost.

Our calculator takes into account your circumstances, requirements and goals, as well as the location of your property and the scale of the project.

Side extensions vs rear extensions (what is the difference in cost?)

Rear extensions are generally more common than side house extensions. This is because most homeowners don't tend to have a huge amount of space at the side of their property. For example, if you have to factor in a party wall agreement.

The average cost of the two types of extension vary. They are dependent on the size of your property and the intended purpose of the new extension.

One thing to bear in mind is that it is generally easier to make a planning application and get planning permission for a rear extension. This can rear extensions cheaper than side extensions in many circumstances. It also means that they are generally easier and quicker to plan in the first stages.

If you're asking which is cheapest - side extensions or rear extensions - you can use our house extension cost calculator to compare and contrast prices, and discover your best options.

What are the average house extension labour costs?

Labour costs for UK extensions vary. There are different skilled tradespeople who perform different tasks, and they have different areas of specialty. The overall costs of a home extension depend on the types of role you need to help you with your project, and how long you need them for.

For instance, if you undergo a bathroom extension, you will need tradesmen to help with pipework; you'll need a qualified plumber for this.

Other professional fees to consider are architectural fees, for designers, planners, structural engineers and qualified architects.

In some cases, you may also require a project manager to assist with running the extension project and ensuring it is completed within a certain timeframe. This is often the case if you have a limited time to complete the work, and if you don't personally have a solid understanding of DIY.

How much does an extension cost in 2020/2021?

If you are hoping to start a home extension this/next year and you want to know more about the 2020 or 2021 extension costs, there are important factors to consider. Property prices are in a constant state of flux. This means that the cost of extending your house is relient on the state of the UK property market.

If you want to extend your living space for yourself or your family, whether or not the property value will be improved by an extension this year may not be an important factor. However, if you want to extend your space because you want to improve its value, it is.

Calculating the specific costs of an extension using an extension cost calculator like ours can help you understand whether an extension this year is worth it.

Is it cheaper to extend or build up?

Generally,it is more cost-effective to extend out rather than build up. So, if you want to undergo a double-storey extension this generally costs more than extending a single storey (like a conservatory extension, or bungalow extension for example).

If you’re trying to find out the cheapest type of house extension in the UK, you can use our specially-created cost calculator. This will take all your circumstances, requirements and constraints into account and will generate you a bespoke cost estimate for your extension based on this.

Equally, you can also call us directly on 01625 885 030 to arrange a consultation with a specialist today.