How to install a bathtub

Bathtubs form an essential part of many bathrooms. Usually rectangular in shape, installed in a corner, and equipped with panels, bathtubs combine elegance and functionality, and come in a range of forms to fit most bathrooms.

Whether clad with panels or fitted with a custom-made cover, bathtubs are equipped with a range of fittings such as a shower set, curtain or even a screen.Given the wide range of different models and layouts, it's impossible to provide a one-size-fits-all tutorial on how to install a bath. Depending on the type of bathtub (a model with built-in taps or custom-fitted panels, etc.) and the bathroom you're working with (a new-build or a renovation, etc.), you may have to consider the following additional steps:

• Removing an existing bathtub or shower.

• Adjusting your water inlet and tap fittings.

• Adjusting your waste pipe, etc.

Required skills

Installing a bathtub requires some plumbing knowledge, especially when it comes to connecting the pipes, waste and trap. You will also have to know how to apply silicone sealant and be able to take accurate measurements, cut panels and use glue. Depending on the installation, you may also be required to cut tiles, use a spirit level, and drill and secure various components.

Completion time

About 4 hours depending on set-up and panel type

Number of people required

1 to 2 people (depending on the weight of the bathtub)

Steps

1. Preparing the bathtub

2. Positioning the bathtub

3. Connecting the overflow, trap and waste

4. Setting up bathtub cladding or panels

5. Positioning the bathtub and fitting the panels

6. Sealing the bathtub

Tools and equipment

• A bathtub with adjustable feet;

• A waste kit and plug;

• A silicone sealant cartridge for the bathroom;

• A sealant gun;

• PVC glue;

• Bathtub panels (custom cladding, wooden panels, etc.);

• Fixing plugs and screws;

• A tape measure and a pencil or marker;

• A straight edge;

• A spirit level;

• A hammer;

• A drill and corresponding drill bits;

• A jigsaw and corresponding blades;

• A hand saw (with PVC blade);

• Sandpaper;

• A tarpaulin cover  (or cardboard) to protect the floor;

1. Preparing the bathroom and taking measurements

Once you have chosen a bathtub to suit your tastes and match the style of your bathroom, it's time to prepare the area where it will be installed.

• Start by fitting the adjustable feet of your bathtub and setting them to the same height.

• Keep in mind that the waste kit will eventually go underneath the bathtub and must not touch the floor. You therefore need to leave a gap big enough to incorporate the waste system plus an extra 5 cm, at least.

• Set the bathtub where you plan to install it and adjust the feet accordingly, making sure the bath is perfectly horizontal using a straight edge and sprit level. Next, mark the wall with the height of your bathtub.

• Remove the bathtub.

2. Positioning the bathtub

With the exception of freestanding or clawfoot models, bathtubs are installed on both adjustable feet and a frame which is attached to the walls.

The next step is therefore to construct your frame, which is made up of square or rectangular sections (20 x 27 mm, 18 x 40 mm etc.). Depending on the type of bathtub and panels, fixings may be supplied.

• Measure the height just beneath the bathtub rim and mark this under the lines you have already drawn on the walls. This will indicate the height at which you need to fix the top section of your frame.

• Cut the frame according to the manufacturer's recommendations (how much of an overhang to leave, etc.). Depending on the length of the frame, screw in your vertical sections at intervals of around 20 to 40 cm using the right type of fixing plug for the material.

• You can seal the top of the frame before fitting the bathtub – this is especially recommended for whirlpool baths, in order to reduce vibrations.

Once you have secured your frame, place the bathtub on top. 

• The bathtub should be be perfectly level (double check this using a spirit level) with the rim of the bath lining up with all the marks you have made.

• The feet are used to keep the bathtub level and to support the base. They should be screwed by hand or using a spanner.

• Once the bathtub is in place, it should rest on the frame as well as the feet.

3. Connecting the overflow, waste and plug

Connecting the overflow and plug

Following the assembly instructions provided, assemble and fit the overflow (usually screwed on to create a seal and connected to a flexible hose) and the plug. Do not forget to remove the various protective plastic covers. Everything must be properly sealed.

Connecting the waste system The trap is connected to the plug on one side and the waste pipe on the other.

• Before permanently gluing anything, try a dry run. If everything fits, sand the end of the trap using sandpaper, coat it with glue and insert the waste pipe.

• Then connect the other end of the pipe to the plug and tighten the nut (do not forget to use a washer). Once the glue is completely dry, let the water run to make sure it is correctly sealed.

4. Fitting your bathtub cladding or panels

Bathtubs are usually clad using custom-made, ready-to-install panels, which have been designed to match the dimensions of your bath. These panels may be supplied with the bathtub itself or purchased separately. They are usually simply inserted and fixed beneath the rim of the tub.You can also purchase cut-to-measure panels designed to be tiled over or wooden panels, that can be painted or decorated.You can also create one-piece cladding using siporex or waterproof plasterboard. If you choose to go with panels that need to be cut, be sure to measure out the height and length before actually cutting anything. You will also have to bear in mind that the panel will need to be inserted in a tilting motion beneath the rim of the bathtub.

It is absolutely crucial to provide an access panel within the bathtub panel in order to access your waste system. The dimensions of this panel are simply traced directly onto the bath panel, which is then cut before the access point is fitted.

Once the bath panels are complete and ready to install, the bathtub is once again removed from its position.

5. Positioning the bathtub and fitting the panels

• With the bath set aside for the moment, lay down a generous amount of silicone sealant all around the top section of the frame.

• Next, reposition the bathtub  back onto the frame. The weight of the bath will compress the silicone seal.

• If equipped with non-removeable panels (plasterboard, siporex, etc.), reconnect the waste trap through the access panel.  

6. Sealing your bathtub 

The silicone seal should be applied once the sides of the bathtub have been covered (tiles, etc.).

Lay a bead of silicone sealant all along the sides of the bathtub where it is in contact with the walls. This seal must act as a waterproof barrier. In order to obtain a tight seal, lay your silicone then smooth it out with your finger using some soapy water.Once this seal is dry, you can then enjoy your bathtub.

-