By Dan Martin

How to Fix and Replace a Mixer Shower

  • Monday 27 December 2021
  • 5 minute read

Fitting a mixer shower is a rewarding DIY project that can transform your daily shower experience. Whether you're looking to master the basics of how to install a mixer shower or need practical advice on how to replace a mixer shower that's seen better days, our guide walks you through both processes. From the tools you'll need to the common pitfalls to avoid, read on to find out more. 

What is a mixer shower tap?

  • A mixer shower combines water from your existing hot and cold water supplies, producing your ideal temperature. There are several types of mixer showers, including: 
  • Sequential mixers, which use a single rotating control to adjust temperature and flow. 
  • Concentric mixers feature two controls, with one lever inside another for separate control.  
  • Bar mixers offer a modern, minimalistic look with distinct temperature and flow controls mounted on a horizontal bar. 
  • Dual control mixers feature independent handles for hot and cold, allowing precise temperature control.  

Each style offers its own benefits, so consider the best option for your bathroom. For more information, read about the key features of Mira mixer showers. 

Tools you'll need

Here are the tools you'll need for changing a shower mixer:   

  • Adjustable spanner or basin wrench 
  • Spirit level 
  • Power drill  
  • Silicone sealant and sealant gun  
  • Pipe slice or hacksaw 
  • Pencil for marking  
  • Tape measure 
  • PTFE tape  
  • Pipe fittings (if needed) 
  • Cloth or towel for cleanup 
  • Safety glasses and gloves  

How to remove an old mixer shower

Follow these steps to replace a mixer valve in a shower safely:

  1. Turn off the water supply: Locate your main stopcock or isolation valves for your shower and turn them off completely. Run the shower briefly to release any remaining water pressure.  
  2. Protect your bath or tray: Lay down an old towel or sheet to catch any drips. 
  3. Disconnect the showerhead and hose: Unscrew these by hand or with a cloth for extra grip. 
  4. Loosen the fixing nuts: Using your spanner, carefully loosen the nuts connecting the mixer unit to the water pipes. Keep a cloth handy, as some water may drip out. 
  5. Remove the unit: Once disconnected, the mixer should lift away from the wall. If it's sealed with silicone, carefully cut through the sealant first.  

Clean the area: Wipe down the tiles and remove any old sealant or limescale.

How to fit a new mixer shower

After removing your old shower, follow these steps to install your upgraded model: 

  1. Check your unit: Ensure you have all the parts required and have read the manufacturer's instructions.  
  2. Position the backplate: Hold the mixer against the wall at your desired height, usually 1.1-1.2 metres from the bath or tray. Use a spirit level to ensure it's perfectly horizontal.  
  3. Mark the pipe centres: Mark where the hot and cold water pipes need to connect. 
  4. Drill and prepare: Use a tile bit for ceramic tiles to avoid cracking. Insert wall plugs if you're securing a backplate.  
  5. Prepare the pipework: Cut the pipes to the correct length using your pipe slice. Flush the pipes briefly to clear any debris.  
  6. Apply PTFE tape: Wrap the threaded connections with PTFE tape to ensure a watertight seal.  
  7. Connect the unit: Attach the mixer to the pipework, hand-tightening the connections before using your spanner.
  8. Secure to the wall: Fix the backplate securely, ensuring everything is level and flush. 
  9. Apply sealant: Run silicone sealant around the base to prevent water from seeping behind the mixer. 
  10. Attach the showerhead and hose: Screw them into place with firm but not forced connections. 
  11. Turn the water back on: Slowly open the valves and check for any leaks. 
  12. Test your shower: Check that the temperature and flow controls work smoothly.

Does it matter which way a mixer shower is fitted?

Typically, in the UK, hot water connects to the left and cold to the right when you're facing the shower. However, if your pipework is the opposite way round, many Mira mixer showers can be adjusted to accommodate reversed supplies. Check your specific models' instructions, as some units have convertible valves or can be fitted either way if needed.

Common pitfalls to avoid

Even experienced DIYers can run into issues, so here are the key ones to avoid when changing a shower mixer:

  • Not flushing the pipework: Always run water through pipes before connecting your new shower to clear any debris that could damage the valve.  
  • Overtightening connections: This can crack fittings or strip threads.  
  • Skipping the sealant: Silicone around the base isn't optional - it's your protection against water damage. 
  • Misaligning pipe centres: Measure twice, drill once. Incorrect spacing means your mixer won't fit properly.
  • Forgetting to check for leaks: Always test thoroughly before you seal everything.

How much does it cost to fit a mixer shower?

If you're weighing up DIY vs calling a professional, the price is a key factor to consider. Fitting a mixer shower yourself costs only what you pay for the unit, and any tools you don't already own. For professional installation, expect to pay between £150 and £200, depending on your location and the job complexity. With the price of a quality mixer shower on top, the total cost of a professional job typically ranges from £250 to £800. 

DIY makes sense if you're comfortable with plumbing basics, but professional installation can give you peace of mind, especially with tricky pipework. Either way, upgrading to a quality shower is an investment in your daily wellbeing, and can add value to your property. 

Shower replacement services

If you'd prefer to leave the plumping to the experts, Mira's professional shower replacement service takes the stress out of upgrading your bathroom. Our experienced installers will remove your old shower and fit your new one with precision and care, letting you enjoy the results. 

Ready to upgrade your shower experience? Explore our range of showers, featuring mixer and electric options, that will transform your bathroom routine. 

Stay inspired

Sign up for Mira emails to hear our latest news, inspiration and offers.