There are some simple and sensible rules to follow when installing a bath. If you’ve decided to fit a new bath in a different position from the old one, this will mean altering the pipe work, which will need to be done before putting the bath in place.
When fitting a bath you have to plan the order in which you will need to work and install any necessary new pipe work. Measure the bath, pipe and bath waste positions, and mark them clearly on the wall in pencil for easy reference.
You may need to run new 22mm (7/8in) supply pipes or add spurs to the existing runs. Do this before you actually install the bath, in readiness for connecting to the flexible pipes attached to the bath taps or mixer bath / shower tap 1.
ATTACHING THE FEET
Before you do anything else, you need to attach the feet assembly. Turn the bath upside down; keep the bath in its packaging so it doesn’t get scratched. On an old-style, cast-iron bath the feet, normally of a ball and claw design, are simply fitted onto predetermined positions using the bolts provided. A acrylic bath may have a supporting frame, with legs attached, which has to be fitted before the bath is installed. On pressed-steel baths, the legs are either similarly bolted on 2, or stuck to the base by means of an adhesive pad attached to the leg assembly. The leg positions are important, so check with the instructions that you have correctly fitted the leg assembly. You may have to adjust the leg heights to suit an uneven floor when you finally install the bath.
FITTING THE TAPS
It is extremely difficult to fit the taps and the waste and overflow once a bath is in place, so you need to this before you finally position it. Slip a plastic or rubber sealing gasket over the tap or mixer tail, then pop this through the tap hole, so the gasket (which will ensure a waterproof seal) sits between the tap and the bath. Slip a top-hat washer over the tail 3,
then tighten the back nut onto the tail to fix the tap or mixer tap body to the bath 4.
Connect the flexible 22mm (7/8in) pipe tap connector 5.
FITTING THE WASTE AND OVERFLOW
Most baths accept a combined waste-and-overflow unit. The waste is the plughole that removes the bath water, and the overflow prevents the house flooding if you leave the bath running while you have a cup of tea. There are basically two types: a compression unit, and a banjo unit. The banjo unit must have the overflow section fitted before the trap, while the compression unit fits directly to the trap itself.
To fit a banjo waste unit, first attach the overflow pipe to its inlet. Fit the washer seal over the overflow grille. Insert the threaded overflow boss from the underside of the bath through the overflow hole and screw the overflow grille onto it 6.
When fitting the waste outlet, slip the rubber washer over the tail and then insert it into the bath waste hole 1.
TOP TIP – Add a bead of silicone mastic sealant to the washer and waste before inserting into the waste hole 2.
Hold the waste fitting, with its washer in place, beneath the bath waste hole 3,
then screw the waste outlet into it. Wrap several turns of PTFE tape around the thread of the waste fitting 4,
then tighten the bath trap nut onto the threaded tail of the waste 5.
TOP TIP – To avoid damaging the chrome, wrap a cloth around the outlet grille before tightening with grips 6.
ENSURING THE BATH IS LEVEL
As a guide for levelling the bath, make pencil marks along the wall with the aid of a spirit level 7.
When everything is ready, check the final position of the bath with the spirit level along both the length and width 8.
Most height adjustments are made by turning the adjustable legs up or down 9.
Cast-iron baths don’t have adjustable legs, but fine adjustment can be made using the bolts and fine washers or packers.
SUPPORTING THE BATH
Try to bear in mind the amount of weight a bath full of water would weigh, then add your own body weight. As a necessary precaution – and in order not to surprise anyone in the room below with an unannounced visit – we suggest that you strengthen the floor either by fixing 19mm (3/4in) plywood under the bath / shower bath, or simply fit two boards beneath the legs in order to spread the weight over a greater area of floor 10.
The added bonus of doing this is that you reduce the movement levels of the bath between its full and empty states, which enables you to make a much more durable and effective water seal between the bath and wall.
MAKING THE SEAL
Once the movement levels between the bath and surrounding walls have been minimized by supporting the bath properly, it’s time to make the waterproof seal between the bath and the adjacent walls. An effective seal is paramount to prevent damp problems occurring later on.
Ensure both surfaces are completely dust and grease free. Grease shouldn’t be a problem, though, if you’re fitting a new bath to new tiles. To get the right finish on the mastic, cut the nozzle to the required width of mastic. Fit the tube in the applicator and start applying from the corner, if there is one, outwards. Keeping your hand steady, move slowly but continuously in the desired direction 11,
using a clean damp cloth to wipe the sealant. While the mastic is fresh, dip a finger in some soapy water and run it slowly over the mastic to effect a smooth shape and ensure contact with both surfaces 12.
A small bowl of equal quantities of washing-up liquid and water is all you will need. Alternatively, try using the handle of a fork or teaspoon to shape the mastic. Allow the mastic to dry for at least 24 hours before using the bath.
It’s important to use good-quality silicone mastic sealant, as it will incorporate essential ingredients, such as elasticity, colour retention and anti-fungal inhibitors.