How to fit a bath

Inspired by the Wickes bathroom guide. This article draws on “Wickes How to Fit a Bath”, a thorough UK step-by-step guide from the Wickes DIY channel. It covers everything from assembling the adjustable frame to connecting the waste — and it is reassuringly honest about the moments where you really do need to turn off the water before you carry on.

1. Turn off the water supply and remove the old bath

Isolate the hot and cold supply at the nearest isolation valves, or turn off at the mains if there are none. Disconnect the taps, overflow and waste. Acrylic baths are lighter than cast iron and can usually be manoeuvred out by two people; cast iron baths are very heavy and may need to be cut up in situ.

Check the state of the floor once the old bath is out. Now is the time to fix any rot, loose boards or damp before the new bath goes in on top of them.

2. Assemble the bath frame

Most acrylic baths come with an adjustable steel or timber cradle frame. Assemble it according to the manufacturer’s instructions before anything else. The adjustable feet are there to level the bath, so fit them loosely at first — you will adjust them once the bath is in position.

Fit the overflow and waste assembly to the bath before you carry it into the bathroom. It is much easier to work on these connections when the bath is upside down on the floor rather than wedged into a corner.

3. Fit the taps before installation

If the taps fit through holes in the bath deck, fit them now with the bath upside down or on its side. Apply plumber’s putty or the supplied rubber gasket under the tap body, thread the tail through the hole, and tighten the back nut firmly from underneath.

Connect the flexi-tails to the tap bodies now too. Trying to tighten these once the bath is against the wall is awkward at best. Getting them on beforehand is a much better use of your time.

4. Position and level the bath

Carry the bath into position — this is a two-person job. Slide it against the walls and check it sits squarely in the recess. Use a spirit level across the rim at several points and adjust the feet until the bath is perfectly level both along its length and across its width.

Most baths should also have a very slight fall toward the waste end — about 5 mm across the full length — to ensure water drains completely. Check this with the spirit level on the bath base rather than the rim.

5. Connect the waste and trap

Connect the flexible waste pipe from the combined overflow and waste assembly to the trap below the bath. The trap keeps sewer gases out and typically connects to a 40 mm plastic drain pipe in the floor or wall. Use push-fit or solvent-weld connections depending on the system already installed.

Check there is a slight fall on the horizontal waste run toward the soil stack or drain — a minimum of 1 in 50 is the standard. Flat or back-falling waste runs will drain slowly and block regularly. Worth getting right first time.

6. Connect the hot and cold supplies

Connect the hot and cold flexi-tails to the supply pipes using compression fittings or pushfit connectors, depending on what is already there. Wrap the male threads with PTFE tape before connecting to prevent drips. Do not overtighten compression fittings — snug plus a quarter turn is enough.

Turn the water back on slowly and check every connection for drips before moving on. Have a dry cloth to hand and look carefully at both the push-fit connectors and the tap-tail connections. Any drip caught now costs nothing; one missed and plastered over costs considerably more later.

7. Fix the bath to the wall

Where the bath rim sits against the wall, fix a batten at the correct height to support it. Alternatively, use bath support clips or wall brackets if the manufacturer supplies them. The bath must not move once installed — any rocking will eventually crack the silicone seal and allow water into the floor.

Check the bath is still level after you have fixed it. Fixing to the wall occasionally pulls one corner slightly. If so, readjust the feet now, not after you have tiled.

8. Seal with silicone and fit the bath panel

Run a neat bead of sanitary-grade silicone sealant along every joint where the bath meets the wall. For a clean finish, apply masking tape either side of the joint first, apply the silicone, smooth with a wet finger, then remove the tape before it dries. Get this right and the finish looks tidy; rush it and it looks exactly like it was rushed.

Clip the bath panel into position and make sure it can be removed if needed — access to the trap and connections is important for any future blockages or leaks. Leave 24 hours before filling the bath for the first time.

When to call a handyman

Fitting a bath is well within a competent DIYer’s ability, but the pipework can get complicated if you are rerouting supplies or working with older copper rather than modern plastic. Call Richard if you need help shifting a heavy cast iron bath, running new supply pipework, or if anything unexpected appears once the old bath is out.