Downstairs Toilet Installation Cost

Want to know how much it will cost you to build a downstairs toilet?

In this comprehensive cost guide, we look at the typical prices for different types of downstairs toilet installations. From the understairs toilets to the small cloakroom toilets. We'll also cover labour fees, material costs and other key factors that may impact the overall price.

To give you a quick estimate, it will likely cost around £3,000 on average, to install a new toilet under the stairs.

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How Much to Install a Downstairs Toilet?

We’ve seen that the average cost to install a downstairs toilet is in the region of £2,000 – £4,000, but this is subject to a number of variables which can dramatically affect the final price.

Firstly, your white goods will be the core purchase. Some people like to install a downstairs shower or full wet-room, especially when there are elderly people residing in the property.

Still, most downstairs WCs (water closets) contain four basic components:

• A Sink
• A Toilet
• A Radiator
• An Extractor Fan or Window

Nowadays, there is an extensive range of sinks and toilets, from the old-fashioned, floor-standing toilet with a raised cistern and pull-down flush chain, to hyper-modern floating toilets with small or inset cisterns.

Likewise, with sinks – they come attached to the wall, on a pedestal, attached to vanity units. With these, you also have the inevitable range of finishes, from very basic to super luxury.

More variables affecting the cost of the project are the size of the downstairs toilet you’re installing, where the new bathroom is being installed (more challenging access raises the price), what your extras are costing (radiator, towel rail, floor covering etc.), and which contractors you choose.

Then, of course, the more things that need installing, the longer the job will take, which will add to your labour costs. So, as you can see, there are lots of variables which can take your downstairs toilet from budget-friendly to quite the extravagance.

Downstairs Toilet Installation Prices

If you want to budget for installing a downstairs toilet, you’ll want to consider six things:

• Types of work involved (plumbing, building, carpentry, electrics, plastering).
• Materials (flooring, tiling, stud walling, wallpaper).
• Decorations and small items (taps, lights, mirrors, towel hanger, shelving).
• Large items (toilet, sink, cupboards, radiator).
• Quality of finish you require – are you more interested in saving money with a basic specification installation, or enjoying the luxury of a high-end specification?
• Finally, how much of the work are you able and willing to complete yourself?

The minimum recommended size for a downstairs toilet is 0.8m x 1.4m (1.12 m² ) – this would be just enough room for a toilet and a small sink, and the door would have to open outwards. For ease of calculations, the prices below are based on a floor space of 1.5 m², or a 0.8 x 1.85m room.

When calculating wall area, this is based upon a rectangular room with two walls at 2m high x 0.8m wide, and two walls at 2m high and 1.85m wide. For ease of calculations, the wall coverings below are based on a wall space of 10.5 m².

Downstairs Toilet Supply Costs

If you’re thinking of installing the downstairs toilet yourself, you'll need to purchase a few items to install it in the room. The basics for a downstairs toilet are a toilet, a sink, tiles and flooring. You will also need to purchase taps to affix to your basin.

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Additional Costs

Whilst the basics of your downstairs WC may be the toilet itself and a sink, there are many other items you may wish to add to complete your room.

If you have the space, adding a bath and/or shower to the room gives you an extra option if you have a big family trying to get ready in the morning.

The bath itself will cost £70 – £1,200 and a shower (the enclosure plus the shower itself) will cost between £200 and £1,400.

If you’re short on space, there is the option of installing a shower unit over a bath, or a walk-in shower bath – the latter costs between £1,500 and £2,000.

Heating

There are two basic types of heating available for use in a downstairs toilet:

• A Standard Radiator
• Underfloor Heating

A standard radiator costs on average £40 depending on size and type, although the size needed for a downstairs WC is likely to be smaller and therefore relatively cheap.

On the other hand, installing underfloor heating will likely cost around £800; however, if the rest of your downstairs has underfloor heating, this will mean no substantial temperature changes between rooms.

One benefit of underfloor heating is that it doesn’t get dusty and then ‘bake’ the dust like radiators do, which often lends the air a stale feel. If underfloor heating sounds like a good option, take a look here at some more information.

Air flow

A downstairs bathroom can get steamy, sweaty and smelly; three excellent reasons to have good airflow! If you have a window in the room, this is the best option as it is free to use and offers additional light. A small double-glazed window will cost approximately £150, but if you’re unable to have a window in your new downstairs toilet, an extractor fan is the next best thing.

It costs on average £300 to have someone supply and fit an extractor fan, but it’s worth it to save the rest of your house from potential damp patches. For more information about whether an extractor fan is suitable for you, and whether it fits your budget, take a look at our page here.

Accessories

The finishing touches to your bathroom are likely the little extras that make it personalised to your needs. Things such as a towel rail, a small shelf, a cabinet, a light fitting or a shaving plug.

It should be noted that any lights must be suitable for bathrooms due to the possibility of steam getting into the electrics.

Labour Costs and Timescales

A lot of the labour costs for your downstairs toilet project will depend on the size of your bathroom. Tiling, flooring and painting work will inevitably cost more the bigger the area they have to cover. However, some items, such as the installation of your toilet and sink, may have a fixed cost, as most will take approximately the same time to install.

You can save on costs by having a multi-skilled labourer complete the work, in which case they may quote you for the entire downstairs toilet job rather than per item. If you hire a qualified bathroom fitter, they will take around 7 to 10 days to complete the work.

When planning your work, remember to allow for jobs which must be run consecutively, such as plastering before tiling, as well as those which can be done simultaneously. It's always best to allow time for unexpected issues to arise.

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Cost Factors of Installing Downstairs Toilet

Several factors can determine your overall downstairs toilet installation costs. Here are the key things you need to consider when planning your budget:

• Your Location — The location of your property affects the overall cost. Labour costs tend to be higher in London and the South East than in other parts of the UK.
• Age of Your Property — Older properties can present challenges such as outdated plumbing, solid concrete walls, or wattle and daub, all of which can add to the costs of installing your pipework, electrics and extractor fan. There may also be limitations if fitting your downstairs toilet in a listed building.
• Waste Disposal — Waste disposal is always a consideration. Your builder will assess the waste generated and arrange the best means of disposal, usually a skip, costing between £60 and £100 depending on the size required.
• Room Decoration — If you're not tiling your walls or having only partial tiling, you will likely want to decorate the rest of the room with either paint or wallpaper. A painter and decorator will often charge £150 to £200 for the day, and depending on the size of the room, it could take 2 to 3 days. You will also need to factor in the cost of the paint or wallpaper.
• Unexpected Issues — Coming across unexpected issues will affect the overall cost of your project, as well as the timeline. A broken or damaged pipe, cracked brickwork, or leaking drains will result in delays and further costs.
• Building Regulation Checks — Finally, check the building regulations for your particular project in your house. Installing a downstairs toilet will usually add value to your home, but without a building control completion certificate, you will find your property hard to sell.

What's Involved in Installing Downstairs Toilet?

Installing a downstairs toilet isn't always simple. A downstairs toilet tends to include a toilet, a sink, a mirror, a radiator or heated towel rail, and a window or extractor fan and requires skills in joinery, plumbing, electrics, plastering, and tiling.

When it comes to rerouting a soil pipe or adding hot and cold water feeds, hiring a skilled downstairs toilet installer for safety reasons will be money well spent.

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Before the Job Starts

• Survey and Planning — Your bathroom fitter will inspect the current plumbing and drainage in your house, as well as near the prospective bathroom. They will identify your boiler or hot water system, give them a good idea of how to lay the pipes around your property, and draft up a quote for the work.
• Removing Existing Fixtures — Any existing flooring and wall coverings will be removed, such as old tiling or wallpaper, along with any existing fixtures and fittings such as electrical sockets.

During the Job

• Electrical Work — If no light fitting exists in the room, your electrician will ascertain the best place and add the wiring.
• Window or Extractor Fan — If you need a new window or extractor fan, your builder will fit it at this stage, both to create the least mess at the start and to provide extra light and adequate ventilation when completing the rest of the work.
• Pipework — Hot and cold water supply pipes will be run under the floorboards to where your toilet and sink will be. If you have a cast iron soil pipe, your plumber will replace all or part of it with a plastic section to connect the new toilet waste pipe.
• Wall Preparation — Your walls will be prepared. Some walls may need insulating, then installing plasterboards, skimming with plaster and painting. A joiner will add any woodwork required, such as your door frame and skirting boards.

After the Job

• Installing Fixtures — Your plumber will install your basin and toilet and connect them to the drainage pipes, along with a small radiator or heated towel rail.
• Tiling and Finishing — A tiler will tile your walls and flooring, and any bathroom cabinets or accessories will be fitted at this stage.

Planning Permission for a Downstairs Toilet

Planning permissions are rarely needed for a downstairs toilet as it will be staying within the original footprint of the house (this comes under the Permitted Development Rights).

You will only need planning permission if the toilet were to be an extension of the property, or if you live in a conservation area or a listed building. If you’re not sure whether you’d need planning permission, you’d best check online.

If you think you do require planning permission, you will need to contact your local planning authority. You will then be able to apply for planning permission online at the cost of around £200.

Building Regulations for a Downstairs Toilet

Building regulations are there to ensure that any work carried out on your property is safe and provides a healthy environment for you, your co-residents, and your neighbours. This reaches from merely ensuring that the walls are stable and won’t fall down, to making sure they are adequately noise-proof.

With regards to a downstairs toilet, a buildings inspector will want to ensure that your building work (if any) is sound, that you have adequate ventilation in the room, that there are no toxic substances used, that the work provides the correct method of waste disposal, that any window installed has the right glazing, and that the room is resistant to contaminants.

You may also find that a downstairs toilet has the requirement to be fully wheelchair accessible, but this is currently down to each local planning authority.

To comply with building regulations, you will need to contact a building control body, which can be your local authority or a private approved inspector. Whichever route you choose, the costs will vary between authorities and private inspectors, but will usually include a deposit, an inspection charge, and a full building notice charge. This could cost up to £750 in total.

What Size Space Do I Need For a Toilet?

You can put a downstairs toilet in a surprisingly small space. In fact, many opt to put a toilet under the stairs! The minimum space for a toilet you will need is 70cm wide by 130cm long, but this would function without comfort. Allowing 80cm x 140 gives you a bit more room to move.

If you are considering installing an under stairs toilet, you will need at least 2m of headroom at the toilet position, and the sloped ceiling can limit where fixtures are placed. Hidden pipework connecting to existing drains may also add to your under stairs toilet costs, and an extractor fan will typically be required for adequate ventilation.

There is a huge range of bathroom items available for fitting into tiny spaces, so although you’ll need to think small, you’ll have a big choice.

Space Saving Toilet Designs

Downstairs toilets come in a lot of different styles, but if you want to take up minimal space, consider one of the following:

• Wall Hung Toilets
• Back to Wall Toilets
• Short Projection Toilets
• Corner Toilets
• Toilet Sink Combination Unit

Let's take a look in more detail.

Toilets which have their back to the wall, hang from the wall, and these take up very little space. However, there will need to be room behind that wall to place the hidden cistern. A back to wall or wall-hung toilet costs between £100 and £450.

A suitable space-saver is a close-coupled toilet – that is, one with a small cistern attached directly behind the toilet seat. Some come as ‘short projection’, meaning the distance between the front of the pan and the wall is minimal, and some are ‘fully shrouded,’ meaning there is no gap behind the toilet for the unsightly soil pipe.

A standard close-coupled toilet will cost between £45 and £350, with short projection ones costing between £160 and £270. A fully shrouded toilet will cost you £140 – £175.

You can also get a diagonal toilet, which will fit neatly into a corner – this can be a great space saver. These cost £150 – £200.

Combination Toilets

Finally, you could get one of the two kinds of combination toilets. Firstly, you can get one with a sink over the top of the cistern. This means you need only accommodate the footprint of the toilet.

You would also need to consider the surrounding space to ensure you don’t have to straddle the toilet to wash your hands! These cost between £185 and £350.

The second type is an all-in-one toilet which comprises a basin, toilet and cupboard, all in one small unit. These come in sizes as small as 90cm wide and 40cm front to back and cost £250 – £380.

Sink & Pedestal Options

If you do not want a combination sink and toilet, you’ll need a separate basin. Again, these come in different styles, suitable for varying shapes and styles of downstairs WC.

• Firstly, you have a classic pedestal basin. These don’t have any specific space-saving features, but they have a small footprint, and you can find ones with a smaller bowl. These cost between £30 and £250.
• An alternative is a cloakroom basin, which attaches to the wall. These tend to be very compact and designed to fit tight spaces. You can get narrow ones, short ones and also diagonal ones made to fit a tight corner. A cloakroom basin costs between £38 and £90.
• If you’d like some extra storage space, you could opt for a cupboard or countertop basin. These can be very narrow and fit into small spaces. You can buy the two items separately (a countertop basin and a separate cupboard), but a combined, small unit will cost between £100 and £600—a countertop basin on its own costs between £30 and £250.

Cost of Removing a Downstairs Toilet

A downstairs toilet can add value to your property, but if you wish to relocate or remove it entirely, a bathroom fitter who can handle plumbing and electrics can dismantle it within a day at a cost of £150 to £250. If you're in any doubt, call in a plumber to ensure your pipes, including your soil pipe, are sealed, and your water is redirected.

If you have hired a professional to do the job, they should have planned for waste disposal. If you are doing it yourself, a small skip will cost around £60, or you can take the waste to your local recycling centre. Be aware that some centres don't accept vans and may charge between £5 and £25 per item.

Checklist: Hiring a Bathroom Specialist to Install a Downstairs Toilet

If you’re looking to hire a professional bathroom fitter to complete this job for you, here are some things you’ll need to complete or consider:

• Are they a member of a recognised trade body? Look for membership of the Association of Plumbing and Heating Contractors (APHC), the Chartered Institute of Plumbing and Heating Engineers (CIPHE), or WaterSafe, the national accreditation scheme for approved plumbers.
• Are they TrustMark registered? Businesses registered with this government-endorsed scheme are vetted for quality workmanship, trading practices, and customer service.
• Do they have insurance? Public liability insurance protects you if something goes wrong during your downstairs toilet installation.
• Will they provide an itemised quote? Ask for a full breakdown of the downstairs toilet cost, so you know what is included and whether there are any additional costs.
• Do they have experience? Ensure they have plenty of experience with installing a downstairs toilet.
• Do they have examples of similar work? Ask to see photos of previous downstairs toilet installations, or check their MyJobQuote profile for examples of previous work.
• Do they have positive reviews? Check their MyJobQuote profile to read feedback from previous customers before committing.

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