How much does a bathroom extension cost?

Bathroom extension quick cost guide

In this cost guide we will talk about:

1. Average cost of building a bathroom extension
2. Hiring professionals for bathroom extension costs
3. Different types of bathroom extension and costs
4. Tips to save money on your bathroom extension
5. Find bathroom extension builders fast on MyBuilder
6. FAQ: Common questions about bathroom extensions

Average cost of building a bathroom extension

Bathroom extension costs can vary quite a bit depending on the size, quality of finishes, and your location. For a basic single-storey extension, you're typically looking at £900 to £1,700 per m² to give you a rough idea.

Take a look at the different sizes of extensions and costs:

Extension type	Average price range
Small bathroom extension (around 10-15m²)	£5,000 to £12,000
Medium-sized bathroom extension (around 15-25m²)	£12,000 to £25,000
Larger, premium bathroom extension (25m² or more)	£25,000 to £35,000+

Smaller bathroom extensions often cost more per square metre than standard ones because, while they use fewer materials, fixed expenses like planning fees and professional services stay the same.

If you’re not sure what size bathroom extension you need, you can quickly get advice on MyBuilder. Just post your job, and include any details about what you’re looking for, and bathroom extension specialists can get back in touch.

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Hiring professionals for bathroom extension costs

A bathroom extension is by no means a minor job. Work is unlikely to be done within a month, and your project will require the hiring and management of numerous different tradespeople, from builders and extension specialists to electricians, plumbers and bathroom fitters.

This table outlines expected hourly labour rates for the professionals you may need to work with during your project.:

Tradesperson	Average hourly rate
Bathroom fitter	£25 to £60
Builder	£25 to £50
Electrician	£45 to £60
Joiner	£15 to £40
Painter decorator	£30 to £50 (usually charged as a day rate)
Plasterer	£15 to £50
Plumber	£25 to £80
Roofer	£20 to £40

Note: When planning a small bathroom extension, consulting with design professionals can optimise space and control costs effectively. Find out how much it costs to hire an architect here.

Different types of bathroom extension and costs

Bathroom extensions come in various styles to suit different homes and budgets, from simple additions to more ambitious builds. Each type varies in complexity, footprint, and features.

Single-storey rear extension: Most popular for bathrooms. Adds space off the back of your home with room for a full suite. Typical cost: £1,200 - £2,000 per m².

Wraparound extension: Extends around a corner (side and rear), ideal for awkward plots needing more light and space. Typical cost: £1,500 - £2,500 per m² due to extra foundations.

Side-return extension: Fills the narrow side alley common in terraced houses, creating a wider bathroom layout. Typical cost: £1,300 - £2,200 per m².

Upwards extension (loft conversion): Converts attic space into a bathroom, great for multi-storey homes. Typical cost: £1,800 - £2,800 per m² including roof work.

If you’re feeling unsure about how much to budget for your bathroom extension, just post your job on MyBuilder today. Then, get a few quotes from different bathroom specialists, so you can compare and find the right price for you.

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Tips to save money on your bathroom extension

Planning a bathroom extension doesn't have to break the bank. Smart choices can keep costs down while delivering good results.

Here are some tips to stretch your budget further:

Pick affordable, quality materials: Go for durable options that look sharp without the premium price tag. Reuse what you have: Refurbish existing fixtures like sinks or taps to avoid buying new ones. Buy in bulk for discounts: Stock up on tiles or fittings when deals pop up to save money overall. Get multiple quotes: Shop around with local builders to find the best rates for your project.

For more tips on what to consider before starting your project, check out our bathroom extension planning guide.

Find bathroom extension builders fast on MyBuilder

Dreaming of a bathroom extension but unsure where to start? Connect with local and verified extension builders on MyBuilder. Whether you’re looking for advice, or want to get your extension project started, it only takes a few minutes to post your job on MyBuilder today, and then let the professionals come to you.

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FAQ: Common questions about bathroom extension costs

How long does a typical bathroom extension take to complete?

A standard single-storey bathroom extension usually takes 8-12 weeks from planning to completion, depending on size, weather, and approvals. Delays can arise from material shortages or inspections, so building in buffer time keeps stress low and ensures quality workmanship.

What are the main challenges associated with extending a bathroom?

Extending a bathroom comes with several challenges. Limited space, especially in older homes, can restrict design options. Plumbing and drainage adjustments often require professional help and can be costly. Structural changes may be needed, particularly if load-bearing walls are involved.

What are the long-term benefits of investing in a bathroom extension?

A bathroom extension offers long-term benefits, including a boost in property value, improved functionality and comfort and a better quality of life. It can also lead to lower utility costs with energy-efficient upgrades and enhance your home’s overall aesthetics and appeal.

How do local regulations impact the cost of a bathroom extension?

Local regulations can significantly impact bathroom extension costs. You may need planning permission, and building regulations approval is usually required to ensure safety and efficiency. Projects in listed buildings or conservation areas often face stricter, costlier requirements. Zoning rules and infrastructure needs, like drainage, can also add to the expense. It’s essential to factor these into your budget from the start.