Before you replace a bathtub with a shower, consider this expert advice
Scrub up on the important plumbing and fitting requirements that come with swapping your bathtub for a shower.
We can see why you’re considering replacing a bathtub with a shower. It’s a smart, space-saving measure that could free up enough room for an extra fitting in your bathroom – and if you’re among the majority of Brits who prefer showering to taking a bath, there’s not much to lose.
There are some important plumbing and fitting factors to bear in mind when installing a shower in place of a bathtub. Get it wrong, and you could end up with a shower that doesn’t work properly, can’t drain or causes leaks and flooding.
To make sure your bathroom transformation goes swimmingly, we interviewed Brian Toward, CEO of Wholesale Domestic Bathroom Superstore, and Paul Bennett, owner of Redstone Plumbing & Heating. With their help, we’ve identified your key considerations, some common mistakes to avoid, and the correct process for replacing a bathtub with a shower.
Recommended shower components
A high-pressure shower head gives you higher power relative to your water supply's flow rate. They're a great choice for limiting water use
How to replace a bathtub with a shower: Step-by-step
1. Assess the space and plumbing
Before you do anything else, measure where your new shower will be fitted. You’ll need to know the height, width and depth of the space so that you can choose a shower tray and screen to fit.
Next, identify the type of hot water supply you’ll use. Depending on your boiler type, it’s likely to be a combi boiler or gravity-fed supply. However, you might choose to install an electric shower that heats water itself, and therefore requires only a cold water supply.
With these specifics confirmed, you can go ahead and purchase your shower, shower screen (or a shower enclosure like this corner-sited model, £165.99, Amazon) and shower tray.
Paul Bennett is the owner of Redstone Plumbing & Heating, a Worcestershire-based company offering a range of bathroom plumbing services, plus boiler installation and servicing as an accredited Worcester Bosch installer. Bennett has 32 years of experience as a plumber, and has owned his own business since the early 2000s.
2. Disconnect and remove the bathtub
“When it comes to disconnecting the bathtub, the biggest thing to focus on is knowing where to isolate the water supply,” says Paul Bennett, owner of Redstone Plumbing & Heating.
“Once you cut a water pipe and haven’t got it under control, there’s a risk of flooding the bathroom. You need to identify the type of water system, which will lead to how to turn the system off and isolate the relevant pipework.”
With the water supply safely and precisely turned off, you can disconnect and remove the bathtub.
3. Adjust the plumbing (and electricity supply, if required)
“Once the bathtub is removed and the plumbing connections are capped, the pipework will need to be adjusted to suit the shower fittings,” says Brian Toward of Wholesale Domestic Bathroom Superstore.
The exact adjustments required will depend on the current configuration of your plumbing and the model of shower you’ve chosen. Some pipework may need to be moved or removed, and it might be necessary to move the drain hole (which you’ll find under the bath). Refer to the guidance supplied with your shower.
“If you’ve cut any of the pipework, make sure it is flushed out before you connect the shower, so that there’s no debris inside that could get stuck in the shower head, valves and so on,” says Bennett.
If you’re installing an electric shower, then you’ll most likely need to have new circuitry installed by a qualified electrician.
4. Prepare the space
With your plumbing prepped, the next stage is to get the space ready for shower installation.
Depending on the condition of the bathroom floor where the bathtub was located, you may need to level the area where the shower tray will be installed (e.g. using self-levelling compound), and you might also decide to tile any newly created floorspace that won’t be occupied by the shower.
If the bathroom walls around the shower space are not covered with a waterproof surface, you’ll need to address this before installing the shower.
Also consider ventilation, as showers come with a higher risk of causing damp and mould than bathtubs do. Installing an electric bathroom extractor fan would be a sensible contingency.
5. Install the tray, screen and shower
Finally, you can install your shower tray, shower screen and the shower itself, in that order.
Confident DIYers will likely be able to fit their own shower tray and shower screens, using adhesives or fixings as specified by the manufacturer. To fit the shower itself, you may require the help of a plumber – especially when it comes to connecting the shower to the water supply.
“After the shower is installed, the final step before using it is to seal everything properly (including the shower, screen and tray) and test for leaks,” says Bennett.
“Make sure everything is sealed correctly by running water over the tiling and the inside of the screen and tray, using the shower head.”
B&Q has a good range of shower sealants at affordable prices.
Brian Toward has served as Chief Executive Officer of Wholesale Domestic Bathroom Superstore since 2012, and previously worked as a Manager at Deloitte. Wholesale Domestic is a 60-year-old family business, retailing bathroom supplies including baths, showers and shower screens.
What are the plumbing differences between a bathtub and a shower?
If you currently have a bathtub with a mixer tap that connects to a showerhead via a hose, you might assume that the same plumbing requirements apply to both baths and showers. This is not the case.
“While both need a water supply and drainage, showers typically need a lower drain position to align with the tray,” says Toward.
“Usually this involves adjusting the pipework to allow proper water flow and prevent pooling (when water gathers in an area that can’t be drained). It’s important to get the drainage slope just right to avoid any issues down the line,” he says.
What to consider before replacing a bathtub with a shower?
Choice of shower
From a plumbing perspective, one of the most important differences between shower models is how the hot water is heated. Here are some of the most popular types of shower and their water supply requirements:
- Electric showers use a cold water supply, which they heat according to the selected temperature setting. It’s relatively complicated to replace a bathtub with an electric shower, as you’ll probably need to get an electrician to run a new mains electricity supply to the bathroom.
- Thermostatic mixer showers are generally used with a combi boiler water supply. This combination of water supply and shower tends to provide good water pressure and reliable heating. Two separate water supplies are required for a thermostatic mixer shower: hot and cold.
- Power showers are a good choice to use with gravity-fed water systems, which often struggle to provide adequate water pressure for a conventional shower. Again, separate hot and cold water supplies are required.
“Think about your water pressure and heating system,” Toward advises.
“Electric showers are ideal for homes with lower water pressure, while thermostatic models are perfect for families because they maintain a consistent temperature.”
Choice of shower tray and screen/enclosure
Your shower tray and shower screen are the components that will integrate your new shower into the bathroom. The tray provides watertight drainage and a safe surface for you to stand on, while the screen keeps the rest of the room relatively dry and can offer some privacy, if required.
When replacing a bathtub, you should ensure your chosen shower tray fits both your style preferences and practical requirements.
“You need to consider both practicality and aesthetics,” says Toward. “Low-profile shower trays are great for a modern, streamlined look, while raised trays can be a practical choice if you need to work around existing pipework,”
Choosing the right shower screen largely comes down to style, although you should carefully measure the bathroom before you choose a model.
“Don’t forget to measure the ceiling height,” says Bennett. “If you’re putting a shower into a room with a sloped ceiling, such as a dormer, then a standard shower screen and enclosure might hit the ceiling.”
Consider how much wear and tear your shower screen needs to take, too.
“Frameless glass screens are incredibly popular for their minimalist look, but framed or semi-framed designs can be a more robust option, especially in bathrooms that are used frequently by a lot of people,” says Toward.
Tiling and ventilation
The bathroom walls around your shower need to be tiled or covered with another waterproof material to prevent water from reaching the underlying plaster and masonry.
“Think about how you’re going to finish the walls – especially whether you’re going to tile them or use a waterproof panel instead,” says Bennett.
“In a professional installation you’d expect a tiled finish, while DIYers can save effort by getting full wall panels to glue to the wall. In either case you’re likely to need specialised tools for the job.”
Ventilation is also required to minimise the risk of damp, mould or damage to the bathroom walls.
“You need to ventilate the space well to stop condensation forming on the ceiling and causing mould,” says Bennett.
“Whereas bathwater is more contained, with a shower the water is up the walls and sprays everywhere.”
Bathroom extractor fans are a popular choice for dealing with water vapour from a shower.
FAQs
Is replacing a bathtub with a shower suitable for DIYers?
Some DIYers do replace their own bathtub with a shower, but this is not a task you should attempt without care, research and thorough preparation.
“I would say it’s more of a job for a pro – although confident DIYers with the right capabilities could do it,” says Bennett. “In the process of taking a bath out and putting a shower in, there are lots of potential eventualities that could require a professional,” he adds.
“For example, if you haven’t correctly identified the water supply type, then you could make a mistake such as fitting a mixer shower to a gravity hot water and cold water mains supply, which would result in lukewarm showers as the water wouldn’t mix correctly.”
If that last sentence made your head spin, it’d be best to hire a plumber to carry out this complicated, risky task.
“I can’t stress enough the importance of consulting a professional if you’re unsure about any aspect of the installation,” says Toward. “Plumbing adjustments can be tricky and even small mistakes can lead to bigger problems down the line. It’s always better to get it right first-time!”
Is it a good idea to replace a bathtub with a shower?
There aren’t many downsides to replacing a bathtub with a shower – especially if you have another bathroom with a bath, or if you much prefer showering to bathing. Under these circumstances, installing a shower in place of a bath will upgrade the bathroom to suit your preferences and save space, all in one go.
If you only have one bathtub, a potential downside to replacing it with a shower would be the effect on your property’s salability or potential appeal to renters.
“I always remind people to think about how this change might impact their home’s resale value,” says Toward. "While a shower can open up the space and make it feel more modern, homes with at least one bathtub often appeal more to families with young children.”
Good luck with your bathroom transformation! If you're confident in your DIY skills and want to take on the task of replacing your bathtub with a shower, be sure to read our step-by-step walkthrough on how to fit a shower. And if you plan on installing an enclosure, rather than a one-sided shower screen, you'll find some useful advice in our guide to shower enclosures.
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Pete Wise is a freelance writer and keen DIYer from Leeds. Pete's tool reviews have featured in titles including Homebuilding & Renovating, Ideal Home and The Independent. He also writes features and news articles for publications such as The Guardian, BBC Good Food and T3. When he isn't busy writing, Pete can often be found at libraries, pubs and live music venues. He finds tile-cutting strangely zen.