Shower Installation Guide

A well-executed installation not only improves your daily routine but also protects your property from the devastating effects of water ingress. From checking flow rates to ensuring electrical safety, a qualified plumber manages the technical complexities that go far beyond just "plumbing in" a unit.

What Does the Work Involve?

• Pre-installation survey: Assessing water pressure (bar), flow rates, and the compatibility of your current boiler or cylinder.
• Isolation and removal: Safely turning off water and electrical supplies before removing the existing unit and any damaged wall coverings.
• First-fix plumbing: Rerouting pipework, installing isolation valves, and ensuring the waste pipe has the correct fall for efficient drainage.
• Electrical work: For electric or digital showers, running new 10mm cabling or installing a dedicated RCD-protected circuit if required.
• Structural prep: Installing a shower tray, ensuring it is perfectly level, and applying waterproof tanking systems to the walls.
• Fitting and commissioning: Mounting the shower valve or unit, connecting the riser rail, and testing for leaks under full pressure.
• Finishing: Applying sanitary-grade silicone sealant and ensuring any tiling or wall panels are watertight.

Typical Costs

Prices vary significantly based on your location in the UK, with London and the South East typically seeing a 20-30% premium. The complexity of your plumbing system—such as moving from a gravity-fed to a high-pressure system—will also impact the final quote.

How Long Does It Take?

• Like-for-like swap: 2 to 4 hours. This is usually a straightforward job if the existing footprint matches the new unit.
• New electric shower installation: 1 day. This includes running a new electrical feed and plumbing into the cold water main.
• Full enclosure and tray replacement: 2 to 3 days. This allows time for the tray to set, tiling to be completed, and silicone to cure.
• Wet room conversion: 5 to 7 days. These projects require extensive floor tanking and specialised drainage installation.

DIY or Professional?

While a confident DIYer might manage a simple shower head replacement, a full installation should be left to a professional. Mixing water and electricity is inherently dangerous; electric showers must be installed by someone competent in Part P electrical safety regulations.

Professional installation is the only way to guarantee your manufacturer’s warranty remains valid. Most brands will reject claims if the unit was not installed by a qualified tradesperson.

Incorrectly installed trays or poorly sealed valves are the leading cause of "slow leaks" that rot floor joists and ruin ceilings below. A professional plumber has the tools to pressure-test joints and the experience to ensure the drainage "fall" is correct.

Choosing the Right Tradesperson

• Check Qualifications: Look for NVQ Level 2/3 in Plumbing or City & Guilds certifications.
• Electrical Competency: If fitting an electric shower, ensure they are Part P registered or work with a qualified electrician.
• Insurance: Always verify they hold Public Liability Insurance (minimum £1 million).
• Experience: Ask for photos of previous "behind the scenes" work, specifically their tanking/waterproofing process.

Questions to ask:

• "Will you be checking my water pressure before recommending a shower type?"
• "Does your quote include the disposal of the old shower and tiles?"
• "Will you provide a minor electrical works certificate for the installation?"
• "How long must I wait for the silicone to cure before using the shower?"

UK Regulations

• Part P (Electrical Safety): Mandatory for electric shower installations in "special locations" like bathrooms. Work must be notified to Building Control.
• Part G (Sanitation, Hot Water Safety): Covers the safe installation of hot water systems and prevents scalding through thermostatic control.
• Part F (Ventilation): If you are creating a new shower room, you must install an extractor fan that meets specific air-extraction rates.
• Water Regulations Advisory Scheme (WRAS): Ensure the products being installed are WRAS-approved to prevent contamination of the mains water supply.

Common Problems

• Poor Water Pressure: Installing a powerful mixer shower on a low-pressure gravity system results in a "dribble." A pump or an unvented cylinder may be needed.
• Incorrect Cable Gauge: Using old 6mm cabling for a modern 10.5kW electric shower is a fire risk. Cables must be sized correctly for the load.
• Inadequate Tanking: Relying on tiles and grout alone to keep water out is a mistake. Professional tanking kits are essential behind the tiles.
• Leaking Trays: Trays installed on "flexing" wooden floors without proper support will eventually crack the silicone seal, leading to leaks.

Frequently Asked Questions

Can I swap an electric shower for a mixer shower?

Yes, but it requires significant plumbing changes. You will need to run a hot water feed to the shower position, which may involve lifting floorboards. You will also need to safely decommission and cap off the existing electrical supply.

Why is my new shower vibrating or making a loud noise?

This is often caused by "water hammer" or unsecured pipework vibrating against joists. It can also indicate that the internal pump in a power shower is struggling with an airlock or restricted supply.

Do I need a booster pump?

If you have a gravity-fed system (a cold water tank in the loft and a hot water cylinder), your pressure may be low. A pump is often required to achieve a satisfying flow rate for mixer showers.

What is a thermostatic shower valve?

It is a valve that maintains a constant water temperature even if someone else in the house turns on a tap or flushes a toilet. It is a vital safety feature for households with children or the elderly to prevent scalding.

How often should I replace the sealant?

Even high-quality sanitary silicone usually lasts 3-5 years. If you notice black mould that won't scrub off or the seal pulling away from the tray, it’s time to strip it back and re-apply to prevent leaks.