Downstairs Toilet Cost: UK Prices for a Cloakroom WC

Downstairs toilet prices

Checkatrade’s downstairs toilet cost guide prices the materials, the labour, the toilet and sink, and a downstairs toilet built as an extension or within the existing building, all excluding VAT.

Item, excluding VAT	Low	High	Average
Materials	£800	£1,100	£950
Labour	£1,200	£1,800	£1,500
Toilet	£50	£200	£150
Sink	£50	£250	£150
Downstairs toilet extension, per m²	£1,900	£2,500	£2,200
Downstairs toilet within the existing building, per m²	£800	£1,000	£900

Installing a downstairs toilet costs around £2,450 on average excluding VAT, Checkatrade says, which is the £950 average for materials plus £1,500 for labour, before any extension or structural work.

Downstairs cloakroom cost

A downstairs cloakroom costs about the same as a downstairs toilet project, around £2,450 depending on its size and specification, Checkatrade says. A cloakroom has the same two fittings as a small en suite with a toilet and basin, and on the ground floor the space for them can come from under the stairs, part of a utility room, cupboard or storage area, or a small extension.

Understairs toilet cost

Under the stairs is one of the most common places for a downstairs toilet, Checkatrade says, because the space already exists, the plumbing runs are often shorter and the structural work may be more limited. The cost varies with the ceiling height, the drainage access, the ventilation and how much renovation the space needs, and compact sanitaryware helps in a tight space.

An understairs toilet is built within the existing building, which Checkatrade prices at £800 to £1,000 per m² excluding VAT, around £900 on average. The space still needs suitable drainage and enough head height.

Converting a room or building an extension

Converting part of a utility room, cupboard or storage area falls in the same £800 to £1,000 per m² band excluding VAT, Checkatrade says, particularly where the plumbing is nearby, access to the external drainage is straightforward and ventilation or electricity is close by.

A small extension costs around £2,200 per m² excluding VAT and is usually the dearer route, according to Checkatrade, because it involves foundations, brickwork, roofing, drainage, windows and doors, structural work and internal finishing.

What changes the price of a downstairs toilet

The closer the toilet is to the existing drainage and waste pipe, the easier and cheaper it is to install, Checkatrade says. The size, the fixtures and fittings, the heating and ventilation, how easy the space is to work in, and the flooring and decoration all change the price too, and a tight understairs space takes longer.

Extra costs to budget for

Groundworks add around £300 and soil removal around £100, Checkatrade says. It also lists extra plumbing and drainage alterations, electrical work and ventilation, flooring, tiling and decoration, radiators or underfloor heating, storage and mirrors, and building control approval as costs to budget for.

What a downstairs toilet quote should include

A quote should outline the labour for the plumbing and drainage, fitting the sanitaryware and any electrical work, along with the heating and ventilation, waste disposal, VAT if applicable and what is excluded, Checkatrade says. Ask whether decoration, tiling and flooring are included, because many quotes cover only first fix and plumbing.

Among the Nottingham bathroom fitters we compare, Rushcliffe Bathrooms and Plumbing in Ruddington takes on plumbing jobs of any size, and A1 Kitchens & Bathrooms in Basford employs its own fully trained fitters and can fully tile the room.

Building regulations for a downstairs toilet

Providing a bathroom in a room where there was not one before is likely to need building regulations approval, the Planning Portal says, so that the room has adequate ventilation and drainage and meets the requirements for structural stability, electrical and fire safety.

Any new toilet should have a means of extract ventilation to reduce condensation and remove smells, the Planning Portal says. For a toilet only, purge ventilation through an opening window or door on an external wall can be used instead, as long as it meets Approved Document F and security is not an issue.

If your home was built after 1999, its ground floor toilet was designed for visiting wheelchair users, and the Planning Portal says a refit should not remove it or make it any less accessible, so altering it may need a building regulations application.

A planning application for installing a bathroom is generally not required unless it is part of a house extension, the Planning Portal says. You do not need to get building regulations approval yourself for alteration and installation work if you use someone registered with a competent person scheme, Nottingham City Council says.

How long a downstairs toilet takes to install

Most downstairs toilet projects take around 4 to 10 days, Checkatrade says, depending on the size, any structural work, the plumbing, the tiling and flooring, the ventilation and electrics, and whether an extension is involved.

How to keep a downstairs toilet cost down

Keep the job simple, with a toilet, a small sink and lighting, and put it near the existing water and waste pipes, Checkatrade advises. If you are confident, strip out the space yourself, take the waste to the tip and do the simple finishing.

Planning a downstairs toilet

Before you ask for quotes, decide whether to convert a space or build an extension and find out where the existing drainage runs, Checkatrade advises.