How to properly install a bathtub? Step-by-step guide

Before starting the installation, it is important to prepare all the necessary tools. This will make the process smoother and more efficient. You will need: a spirit level, adjustable spanner and pipe wrench, measuring tape, and a silicone gun. In addition to tools, have installation materials ready, such as sanitary silicone and sealing tape. Depending on the bathtub model, you will also need a frame or adjustable legs, as well as a suitable trap compatible with the bathtub and the waste and overflow set. There are two main options: a traditional plug or a click-clack system, which is becoming increasingly popular.

Before placing the bathtub, proper waterproofing of the bathroom is essential. The surface beneath the bathtub must be stable, dry and level - the acceptable deviation is a maximum of 1-2 mm. Load-bearing capacity is also important and should be at least 250 kg/m². It is recommended to cover the area under the bathtub and extend 15 cm beyond its outline with a liquid membrane or waterproofing foil. Proper placement of connections is crucial-the drain should be positioned directly under the bathtub outlet. The standard bathtub height is 55-60 cm from the floor, but this may vary depending on the model and installation system.

When choosing a bathtub, you also need to decide on the installation system. There are three options: a frame, adjustable legs, or a polystyrene support. The exception is corner bathtubs, which require a dedicated frame. Among these systems, the frame is the most stable, as it transfers weight to the floor rather than to the edges of the bathtub. Depending on the model, frames may vary. Adjustable legs are a simpler and more affordable solution, offering 4-6 support points and height adjustment via screws. An alternative is a polystyrene support with a pre-formed shape tailored to the bathtub. Installation is quick and does not require adhesives or a frame.

Which should you choose? Compared to legs, a frame is more stable and works best for corner and larger bathtubs. Legs are simpler and suitable for standard rectangular models. A polystyrene support stands out for its quick installation and good sound insulation.

The next stage is the installation process itself, which consists of several steps. How do you install a bathtub?

Step 1 - Install the frame or legs

Turn the bathtub upside down, attach the frame rails, and install the adjustable legs (tighten according to the manufacturer’s instructions).

Step 2 - Install the bathtub trap

Next, install the waste and overflow set with seals and attach the low-profile bathtub trap.

Step 3 - Position the bathtub

Place the bathtub in its final position, leaving a 5-10 mm gap between the tub and the wall.

Step 4 - Level the bathtub

Use a spirit level to adjust the legs. The maximum deviation should not exceed 2 mm.

Step 5 - Secure the bathtub

Fix the bathtub to the wall using mounting brackets or anchors every 40-60 cm with 8-10 mm wall plugs.

Finally, install the bathtub faucet-typically 15-20 cm above the rim. Before enclosing the bathtub, it’s important to perform a leak test by filling it with water and observing the installation for 15-30 minutes.

When considering how to enclose a bathtub, there are several options. Quick and cost-effective solutions include ready-made enclosures made of acrylic or MDF panels tailored to the bathtub model. The downside is limited customisation. Another option is a built-in enclosure using a metal frame, plasterboard, and ceramic tiles. If you’re looking for a more aesthetic and unique finish, this option offers greater design flexibility.

An essential element is an access panel, which provides access to the trap and plumbing. Expansion gaps are also important-a 2-3 mm gap between the floor and the enclosure prevents cracking caused by structural movement.

Once the bathtub is in place, the next step is sealing it with silicone. Due to high humidity, it’s important to use bathroom-grade silicone resistant to mould and fungi. Where and how should silicone be applied? Apply a thin layer along the joint between the bathtub and the wall, then smooth it with a finger dipped in soapy water or a finishing tool. Additional protection can be provided by sealing tape placed beneath the tiles.

A leak test is crucial and should be carried out before enclosing the bathtub. Fill the bathtub with cold water up to the overflow and observe the drain and trap for 15-30 minutes. After applying sanitary silicone, it is recommended not to use the bathtub for 24-48 hours.

Absolutely. Acrylic bathtubs are lightweight but require a frame and careful handling to avoid cracks. Steel bathtubs are heavier and more stable but need sound insulation, such as foam or acoustic mats. Corner bathtubs require a dedicated frame and precise alignment with wall angles. Freestanding bathtubs are installed directly on the floor and require a dedicated drain and freestanding faucet. Composite bathtubs are very stable and do not require additional reinforcement, but they are also the heaviest.

Installing a bathtub is not overly complicated and can be done independently. However, there are several mistakes to avoid, as they may lead to installation issues or problems during use. Here are the most common ones:

Mistake 1 - Not using a spirit level

Incorrect levelling leads to uneven water drainage and silicone cracking.

Mistake 2 - Skipping the leak test

Some homeowners forget to perform a leak test. Detecting leaks after enclosure means dismantling the structure and costly repairs.

Mistake 3 - No expansion gap

If the building settles or the bathtub flexes, the enclosure may crack.

Mistake 4 - Incorrect trap selection

If the trap is too tall, incompatible, or poor quality, it will be difficult to replace once enclosed.

Mistake 5 - No access panel

Without access to the trap, any repair will require breaking the enclosure.

Mistake 6 - Overtightening screws in acrylic bathtubs

This can lead to cracks in the bathtub structure.

What height should a bathtub be? The standard height is 55-60 cm from the floor to the top edge; it depends on the frame and legs.

Can I install a bathtub myself? Yes, with proper preparation and tools-but having a second person to help is recommended.

How much does professional bathtub installation cost? Hiring a plumber usually costs a few hundred PLN.

How can I cover the bottom of a bathtub without building an enclosure? You can use ready-made panels, a panel enclosure, or a bath screen-quick solutions without construction work.

Is waterproofing required under the bathtub? Yes, it is recommended to use liquid membrane or waterproofing foil under the bathtub and extend it 15 cm beyond its outline.