How To Fit A New Bath

Learn how to install, plumb and seal a new bathtub in your home with professional results. Follow our step-by-step DIY guide.

Step 1. Mark Your Positions
Step 2. Attach Legs
Step 3. Drill Tap Holes
Step 4. Isolate the Water Supply
Step 5. Fix Taps, Overflow and Waste
Step 6. Even the Load
Step 7. Fix the Bath into Place
Step 8. Prepare to Seal
Step 9. Apply Sealant
Step 10. Fitting Your Bath Panels

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How To Fit A New Bath

Installing a new bathtub in your home completely revitalises your bathroom and gives you a real focal point to plan your decor around. However, since it is not often you make a change of this size, make sure you get it right.

Here at Victorian Plumbing we have complied this expert DIY guide on how to prepare a new bathtub, fit and plumb it correctly, attach a bath panel and then finally apply a lovely straight line of bathroom sealant that gives it a real professional finish.

This is an intermediate level job; you will require some knowledge of plumbing and how a bathtub goes together, an understanding of legal requirements needed for this job*, and a healthy dose of confidence in your own ability .

What You Will Need

● Spirit level
● Steel wool
● Pipe cutter
● Sanitary sealant
● Sealant gun
● Pipe cement
● Adjustable pipe wrench
● Tape measure
● Adjustable wrench
● Plumber's mait
● Screwdriver set
● Drain cleaner
● Pipe joining compound
● Masking tape
● Fairy liquid
● Wooden battens
● PTFE tape
● Electric drill with hole saw attachment

All set?

Step 1. Mark Your Positions

Mark your bath, waste pipe and pipe positions on your wall with pencil. Take this opportunity to line up your existing plumbing with your new fittings. If any of your plumbing requires alterations or additions, do this now.

Step 2. Attach Legs

Turn your bath upside down, being careful not to scratch or damage the tub, and fix the legs as per the manufacturer’s instructions. Often with acrylic baths, the legs will come attached in a space-saving way for shipping, but they need to be removed and attached properly.

Step 3. Drill Tap Holes

Some baths do not come with pre-drilled tap holes. If this is the case, you must drill some yourself before you continue.

Choose where your tap is going to go and measure the size of hole you will need. Often baths without tap holes will come with a template for you to work out the positions of your taps and the size of hole you will need.

You may find it difficult to mark your bath with a pencil. Our top tip is to lay down some masking tape first. Also, always remember to check, check and check again when it comes to your positions and measurements. You cannot un-drill a hole from your nice new bath!

Use a hole saw drill bit to drill a hole into the bath. Go slow and steady, aim to get the hole a few mm bigger than your tap pipes, so you can be sure of a nice fit once washers and bolts etc. are installed.

Step 4. Isolate the Water Supply

It is now time to work on your current plumbing, so it is best to isolate your water supply using your isolation valves. These are small, metal valves with a screw-head in the middle that you can turn to turn off the water to an individual tap. If you do not have isolation valves then you can switch off using the mains. We recommend perhaps taking this opportunity to fit isolation valves, they will be helpful for any future projects.

Step 5. Fix Taps, Overflow and Waste

Often, bathroom taps will already have flexible tap connectors, this makes the job lot easier. However, if your taps are fitted straight to metal pipes, reconnecting two solid pipes can be troublesome, so it may be worth cutting the pipe down a little and fitting flexible tap connectors. This saves you time in the future and you can be sure the connection is nice and fresh. Connect the flexible water pipes onto your taps, but do not connect anything to your existing plumbing at this point.

You should now have a bath with legs, waste and taps fitted, but not connected to your plumbing.

Step 6. Even the Load

Bathtubs can be heavy, especially when they are full of water. To help your floor deal with this weight, place your bath atop two wooden battens. This creates a larger surface area and spreads the weight of your bath more evenly.

Step 7. Fix the Bath into Place

At this point, line up your bath as you want it, and use a spirit level to make sure your bath is level. If it is not, you can adjust the individual feet until it is correct. Mark the floor with positions for your battens, and mark the battens with where the feet will sit. You can then remove the bath and screw battens into place. Then put the bath back on to the battens and screw into place atop the wooden stands.

Now you are ready to fix your taps, waste and overflow to your internal plumbing as per your manufacturer’s instructions. This is a case of connecting the flexible tap connectors to the right internal water pipes, you can use PTFE tape around any threaded connections to provide an extra strong seal. Your waste and overflow pipes must also by sealed tight to the bathroom's internal soil pipes beneath the bath.

Step 8. Prepare to Seal

Clean the area you are going to seal of any dust, grime or grease with a scouring pad and some methylated spirit. Make sure you use gloves as methylated spirits can be harmful. Our top tip: Before you begin sealing the bath, fill the tub with a few inches of water. This extra weight opens the joints between the bath and the wall, so the sealant runs between and helps to create a stronger bond.

Step 9. Apply Sealant

Use two strips of masking tape, one along the wall, one along the bath, leaving a few millimeters of space for where the sealant needs to go. This prevents sealant from running up onto the tiles and helps keep your sealant in a neat, straight line. Draw a bead of sealant slowly and smoothly along the gap between your bath and your wall.

Remove your masking tape before the sealant sets. Run a plastic former tool, or something roughly the right size, along the sealant line, wiping the tool with tissue every so often to remove any excess and keep it neat. We recommend re-purposing an old lolly ice stick for this - nice pliable wood, easy to get hold of and they have lovely rounded edges that will smooth your sealant beautifully.

Finally, wet your finger with a water and fairy liquid mix, then run it slowly along the sealant line. This smooths out the sealant, removes any bumps and helps form a tight bond.

Step 10. Fitting Your Bath Panels

You can now install your bath panels. Often these will include clips that attach to your bath. However, if they don’t, you need to use more wooden battens. Attach to the floor so the panel will touch them when it is in place. Drill holes into your panel and screw our panel to the batten. The panel should fit in under the lip of your bath, then stand plumb to your wooden battens, and be attached by screws.

Once the sealant has started to cure after a few hours, you can drain the water from the bath. This causes the sides to spring back into place, and form an even stronger bond with the sanitary sealant. Remember to switch the water back on from the isolation valves and run both taps quickly to make sure everything is in working order with no leaks. Leave to dry for 24 hours before using the bath properly.

*Please remember to check your local building regulations for any steps and procedures you need to take in order to keep your renovation in line with health and safety laws.

Hopefully this step-by-step DIY guide will give you the confidence to change your bath to nice new model and give your whole bathroom a lift. If you have any questions or concerns, please leave a comment below or connect with one of our social media channels and we will endeavour to get back to you with an answer.