How Much Does a Downstairs Toilet Extension Cost


Adding a downstairs toilet extension to any home can be a wonderful addition and add value to your home. It’s essential, however, to carry out plenty of planning before embarking on a downstairs toilet extension. Keep reading to find out the best ways to start planning.

Why choose a downstairs toilet extension?

Firstly, it’s great to work out why you would like a downstairs toilet extension, as this reason is likely to have a big impact on the size and cost of the extension.

There are many reasons to choose a downstairs toilet extension, such as easier accessibility, simply an additional toilet in a busy household or one to use when you have guests visiting.

If you already have a downstairs toilet but find that it's too small, a downstairs toilet extension is the perfect solution. Perhaps you currently have a small understairs toilet with limited space or a toilet cloakroom with shared toilet and utility space and are looking for more space.

How much does a downstairs toilet extension cost?


The cost of a downstairs toilet extension will depend on factors such as its size, where the extension is to be constructed and the age of your home amongst other reasons. Keep reading to find out more.

If you’re creating a downstairs extension purely for a downstairs toilet and not part of a wider single-story extension this is likely to lower the cost of the extension. A simple downstairs toilet extension can cost between £1,900 - £2,500 say Checkatrade. Please bear in mind this cost covers the extension alone and not any fixtures, fittings, or labour costs.

There are however other ways to create a downstairs toilet extension. For example, you may have an existing unused outside toilet that you would like to convert into a downstairs toilet, making it accessible from inside the house. This might involve knocking walls down but generally won’t cost as much as a brand-new extension. We suggest contacting a professional for a quote on your specific circumstances in the case of an outside toilet conversion.

You also need to consider labour costs when thinking about any extension or a downstairs toilet conversion too, as these are likely to impact your budget. Checkatrade states the average labour cost for a downstairs toilet extension is £1,500. However, this will differ from project to project depending on the work carried out and therefore it should be remembered that this is only an average cost. You could find your project costs significantly more or less than this depending on your circumstances.


Other areas can potentially increase the cost of a downstairs toilet extension such as the positioning of pipework and electrics as well as the quality of materials being used. For example, if you choose to use basic materials such as vinyl flooring and basic ceramics your project is likely to cost significantly less than if you used marble tiles and higher-end ceramics.

However, one area that could pose greater issues is the age and grade listing of your home. If planning permission is granted you may find that you must work to a specific build plan, so any new building works stay in keeping with the original design of the home.

Does a downstairs toilet add value?


In most cases adding a downstairs toilet extension will add value to your home but this isn’t always the case. Checkatrade states that a downstairs toilet can add up to 5% to the value of your property. Properties however with only a downstairs bathroom actually go down in value.

It’s unlikely that a new downstairs toilet will be your only toilet in the home, but this is something we wouldn’t recommend as having your only bathroom downstairs can make it harder for you to sell your home in the future.

Now, if your downstairs extension is going to be larger than just a downstairs toilet the extension itself is likely to increase the value of the property, which can be anything from around 5 – 8% according to Checkatrade.

Will I need planning permission?


In most cases you are likely to need planning permission for a new toilet extension, therefore, it’s always best to contact your local planning authority for confirmation before proceeding with building or planning.

Other areas to consider are whether you’re planning on building on or near the boundary of your property as you will then need to consult the Party Wall Act. This act was created to help prevent disputes with neighbours and resolve any issues between parties relating to the boundary of properties.

Building regulations must also be met for a downstairs toilet. Once work is complete a certificate must be provided to show these regulations have been met. If completing any work yourself, this will fall on you to keep to building regulations, however, if you hire someone to carry the work out this will fall with the contractor/builder.

How big does a downstairs toilet need to be?


Generally, a downstairs toilet should be a minimum of 70cm x 130cm, however, this doesn’t mean you can’t go bigger if you have the space. This is especially true if you’re thinking of adding items such as a vanity unit or bathroom cabinet as they will take up much more space than just a small toilet and basin.

You also need to consider space if you want to create an accessible bathroom for a less able family member. In this case, you might need to invest in items such as a disabled toilet and grab rails, so making sure you have plenty of manoeuvrable space is essential.

However, worry not if you only have 70cm x 130cm to play with as there are plenty of space-saving toilet and basin options. You can even get a combined toilet and basin unit, either with or without storage space or a small cloakroom suite. Keep reading to find out how to make the most of the space available.

How long does it take to fit a downstairs toilet?

The length of time it takes to fit a downstairs toilet much like the cost of installing one will depend on a wide range of factors. From the size of the room and the positioning of pipework and electrics to the quality of materials you choose, there are many reasons for a variation in the time it takes to fit a downstairs toilet.

This is then made longer when creating a downstairs toilet in a new extension. On average, it can take anywhere between 4 – 14 days but this can take longer when factoring in the time it takes to build the extension itself.

How to maximise space in a small cloakroom?


Once you’ve created your new downstairs toilet extension, now’s the time to think about ways to maximise your space. This can be anything from a corner or short projection toilet to wall hung basin or even a toilet with a basin on top.

If you’re looking to include some storage space in the space then a bathroom mirror cabinet is a good option, as it takes up minimal space and can easily be fitted on the wall above your basin or toilet.

For more information on making the most of a small bathroom take a look at the following posts - Small Cloakroom Ideas - Make the Most of Your Small Bathroom - Small Toilet Ideas.

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