How to Hire a Bathroom Fitter

What makes hiring a bathroom fitter different

Almost everything that determines whether a bathroom lasts is invisible once it is finished.

Waterproofing sits behind the tiles. Pipework sits under the floor. Electrical zoning is a set of rules you cannot see being followed. A bathroom that looks immaculate on handover can be failing quietly from the first week.

This makes the trade unusual: the quality you are paying for is precisely the part you will never see, and the failures arrive long after the invoice is settled.

Registrations and accreditation

Electrical work in bathrooms is governed by zoning rules that restrict what can be installed where, and much of it is notifiable under Part P in England and Wales. Confirm who is registered and who issues the certificate.

Any gas work, moving a boiler, altering a heating circuit, legally requires Gas Safe registration.

Ventilation is covered by Part F of the Building Regulations, and the numbers are specific. A bathroom with a bath or shower needs an extract rate of at least 15 litres per second for an intermittent fan, or 8 l/s for a continuous system. A separate WC needs 6 l/s.

Two things go wrong regularly: the fan is undersized for the duct run, so it spins but does not achieve the rate; and it is ducted into the loft rather than outside, which moves the moisture problem rather than solving it.

Ask what rate the fan is rated at, where it terminates, and whether it has an overrun timer. A bathroom with no openable window needs one regardless.

The waterproofing question

This is the question that separates a good bathroom fitter from a bad one, and most homeowners never ask it.

Tiles and grout are not waterproof. Behind them there should be a proper tanking system in wet areas, a membrane or boarding designed for the purpose. In a shower enclosure or wet room this is not optional.

Ask what system they use, where it extends to, and ask to see it before tiling starts. A competent fitter will happily photograph it. Someone planning to tile straight onto plasterboard will become evasive, and you will have learned something crucial while it can still be fixed.

Older properties and what lies beneath

In period properties the floor is often the problem.

Joists may not be deep enough for the loading of a tiled floor or a filled bath. Existing build-up may mean the new floor sits proud of the doorway. Old pipework may need replacing rather than reconnecting.

None of this is visible at quotation. A good fitter will say so and give you a rate for what they might find. A quote that assumes everything beneath is fine is a quote that will change.

What a good bathroom quote looks like

• The tanking or waterproofing system, named
• Whether the floor is being replaced or overlaid, and what happens if joists need work
• Electrical work included, and who certifies it
• Extractor fan, and whether it meets the ventilation requirement
• Tiling: area covered, tile size assumed, and whether you are supplying
• Removal and disposal of the old suite
• Making good, plastering, decorating, sealing
• What happens if pipework is found to need replacing

Deposits and payment stages

Suites and tiles are ordered in advance, so a materials deposit is normal, 15-20%, though smaller than a kitchen, because the goods are standard rather than made to measure.

Sensible stages: materials delivered, strip out and first fix complete, waterproofing complete and photographed, tiling complete, second fix and commissioning.

Making waterproofing its own signed-off stage is unusual and worth insisting on. It is the only moment the most important part of the job is visible.

Hold the final 10% until the bathroom has been used for a week or two. Leaks and failures show up in use, not at handover.

What usually goes wrong

• Tiling directly onto unsuitable substrate, causing failure within a year
• Inadequate or absent tanking in shower areas
• Floor levels leaving doors that will not close
• Falls in wet rooms set wrong, so water does not drain
• Silicone and sealing done poorly, causing slow leaks at edges
• Electrical work uncertified, surfacing when you sell

Questions to ask a bathroom fitter

• What tanking system will you use, and where does it extend to?
• Can I see the waterproofing photographed before tiling starts?
• Who does the electrical work and who issues the certificate?
• What happens if the joists or floor need work?
• Is an extractor fan included, and does it meet the ventilation requirement?
• Is making good included?