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Last updated on May 3rd, 2024

How much does a bungalow extension cost?

Bungalows are becoming more and more popular with younger people due to their development potential. Find out how much the average bungalow extension costs.

There are lots of options to choose from with a bungalow extension. You can increase the overall floor space, increase room sizes, add room height, create an open plan layout and even add an extra floor.

For a breakdown of each cost, we spoke to the online estimators at My Build Estimate – a professional estimating company monitored by the Royal Institution of Chartered Surveyors (RICS). This guide features the estimated bungalow extension cost examples they provided.

When calculating the average costs one important consideration is whether to extend upwards or outwards. The costs in the following table give examples of both these choices.

How much does a bungalow extension cost?

Type of extensionCost + VAT
(Range low - high)
Average cost
Single storey bungalow extension costs (per m2)£1,900 - £3,500£2,750
Dormer bungalow extension cost (Based on 30m2)£40,000- £75,000£50,850
Bungalow loft extension cost (Based on 50m2)£70,000 - £140,000£105,000
Bungalow roof extension costs (Based on 20m2)£27,000 - £45,000£35,000
Extension planning drawings cost£950 - £2,500£1,250

Our costs are ballpark averages – get a local tradesperson to quote now

For the prices in this guide, we have considered the following:

  • The costs are based on standard construction
  • Costs are based on concrete tiles
  • No allowance for slates
  • No allowance for special roof finishes e.g. lead/zinc/aluminium

With these factors in mind, the average single-storey bungalow extension cost is £2,750 per m².

Extending outwards is similar to any single-storey extension, and extending upwards will be similar to a loft extension. For further information regarding typical home extension costs and factors, view our house extension cost guide.

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Dormer bungalow extension cost

The average dormer bungalow extension cost is £50,850 based on 30m².

A dormer extension is added to the roof of any bungalow or house. It protrudes from the slope of the roof to give extra floor space and is often known as creating a floor and a half bungalow.

If done well it can be a stunning feature for any home, and a window is often added to allow extra light to flow into the new space. Planning permission is not usually necessary.

Bungalow loft extension cost

The average bungalow loft extension cost is £105,000 based on 50m².

The loft of a bungalow is an opportunity waiting to happen and most homeowners do not make the most of this space. Providing the loft is at least 2.3m high, the roof will not need to be lifted, so you can do a loft conversion, which is cheaper than a full extension.

You may need to strengthen the current beams in the loft. And if adding a bathroom, plumbing will need to be installed at an additional cost.

Single storey bungalow extension costs

The average single-storey bungalow extension cost is £2,750 per m².

A single-storey extension is a popular way to extend a traditional bungalow, as it can be added onto the side, rear, or occasionally the front of the bungalow.

A single-storey extension is perfect for adding extra rooms or extending current rooms. Bungalow rear extension costs and bungalow side extension costs per m2 are very similar, while front extensions can cost more and have additional planning permission challenges.

Bungalow extension work in progress

Bungalow roof extension costs

In general, extending the roof of a bungalow involves adding an extra half a storey, bringing the total bungalow height to one and a half storeys. When you require more headspace, it is possible to lift the current roof of your bungalow to the full height of a two-storey house.

This may extend over the entire bungalow or a smaller section but can greatly improve the aesthetics of your home.

The average bungalow roof extension cost is £35,000 for a 20m² area.

Factors affecting bungalow extension costs

It is essential to consider several factors when calculating your exact bungalow extension cost. The following factors (listed below) may increase or decrease the average costs we have listed in this guide:

  • Architect and structural engineer fees: Depending on the scope of your new extension it may be necessary to hire an architect or structural engineer to draw up detailed plans and help you make the most of your new space. Costs can be found in our guide to architect fees.
  • Size: The bigger your extension, the higher the overall cost.
  • Quality of materials: When planning your bungalow extension choosing higher quality materials will increase the quality of the job at an additional cost.
  • Groundworks: When extending a single storey, new foundations and groundworks will need to be excavated and depending on the work required the cost will vary.
  • Stairs, windows and doors: Adding windows and doors are essential for access and to allow light and fresh air into the new extension. If adding an extra floor, the cost for stairs will need to be factored in too.
  • Purpose of the room: Whether your room will be used as a bathroom or kitchen will also raise the extension cost due to the need for electrics and plumbing installation.
  • Plastering and decorating: Once your bungalow extension is complete you will need to have the space plastered and decorated.

Completed bungalow extension cost

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Do I need planning permission and building regulations for bungalow extension?

It’s very much dependent on the type, location and size of your extension. Your best bet is to speak to your local authority.

Until you have found out whether you need planning permission or not, you should not begin your new bungalow extension.

In addition, any new extension space must adhere to building regulations. These are in place to protect the safety of both you and the building.

How long does a bungalow extension take?

In general, a single storey extension will typically take from three to four months, although you should factor in the possibility of delays due to unexpected problems.

Can I build a bungalow extension myself?

Building an extension is by no means a simple job, it is difficult and extremely hard work. Even professional tradespeople work in a team and take months to complete a bungalow extension. It is vital that anyone undertaking a project as big as this has the correct training otherwise you put the health and safety of yourself and others at risk.

In addition, extensions must comply with building regulations and unless you have experience with this kind of job, the quality of the extension will be nowhere near that of a professional.

We would strongly recommend you hire a professional. To find a local, reputable, tradesperson in your area and get a personalised bungalow extension cost use our free search feature.

Should I do a bungalow extension?

Of course, as long as you have budgeted for the extension and it will give you the home you’ve always dreamed of, it’s a great idea!

You can truly transform your bungalow with an extension and conversion. That’s what Tina did in Ruislip, London – she used Checkatrade to research bungalow extensions before booking a quality trade to do the bungalow extension project for her.

Make sure to check out her stunning new home!

Tina's bungalow extension/conversion before and after

Key takeaways for bungalow extensions

  • Loft, dormer, rear and side are all types of bungalow extensions
  • The bungalow extension cost is affected by factors such as size, location and quality of materials
  • Bungalow extensions usually take three to four months
  • Planning permission may be necessary and building regulations must be complied with
  • Building a bungalow extension is time consuming, difficult and dangerous unless completed by a fully trained professional
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We check the reviews on Checkatrade are from real people, and that trades meet our high standards.

Working with professional estimators, we collate cost estimates for the common home improvement and repair jobs in the UK.

All the costs are estimates only. For accurate costs for your particular requirements, you are encouraged to reach out to professional tradespeople to receive a quote for your job.

Our estimators are Chartered Members (MRICS) of the Royal Institution of Chartered Surveyors and Members of the Chartered Institute of Building (MCIOB). See full disclaimer.

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What others think of this article:


That's great to hear, thanks Cherylin!

Cherylin Bryant

Very usefulland helpfull service

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