A bathroom renovation is one of the most disruptive home improvement projects you can take on. It’s also one of the most rewarding when it goes well. Done properly, you’ll add value to your property and have a space you actually enjoy using.
The plumbing side of a bathroom renovation is what makes the difference between a project that goes smoothly and one that drags on for weeks with unexpected costs piling up. Most homeowners focus on tiles, suites, and finishes when they’re planning their bathroom. The plumbing tends to be an afterthought, which is when problems start.
This guide explains what’s involved in the plumbing side of a bathroom renovation and how to plan properly so the project runs smoothly from start to finish.
What’s Involved in Bathroom Renovation Plumbing?
Plumbing isn’t just about connecting up the taps and the toilet. A proper bathroom renovation involves several stages of plumbing work.
Strip-Out and Disconnection
Before anything new goes in, the old bathroom needs to come out. This involves:
- Disconnecting and removing the old bath, basin, toilet, and shower
- Capping off existing water supplies and waste pipes
- Assessing what’s behind the tiles and under the floor
- Identifying any hidden problems with existing pipework
This stage often reveals issues you couldn’t see before. Corroded pipes, joints that have been leaking slowly for years, or pipework that doesn’t meet current standards all show up once the old bathroom is removed.
First Fix Plumbing
First fix is everything that happens before the walls go back on and the tiles go down. It includes:
- Running new hot and cold water supplies to each fixture
- Installing waste pipes for the bath, basin, shower, and toilet
- Fitting isolation valves so individual fixtures can be turned off without disrupting the whole house
- Pressure-testing the system before it’s hidden behind walls
Getting the first fix right is crucial. Once tiles are down and walls are sealed, going back to fix a leak means significant damage and cost. A good plumber takes the time to do this properly.
Second Fix Plumbing
Second fix is the visible plumbing, the bits people actually see:
- Fitting taps, mixers, and shower fittings
- Installing the bath, basin, and toilet
- Connecting up the waste traps
- Final pressure testing and commissioning
This is the satisfying stage where the bathroom starts to look like a finished room.
Additional Plumbing Work
Depending on what you’re planning, your renovation might also need:
- Boiler upgrades if your existing system can’t handle the new fittings
- Pressure-boosting pumps for power showers
- Underfloor heating installation
- Towel rail connections
- Shaver socket installation (usually electrical, but coordinates with plumbing)
- Extractor fan ducting
How Long Does Bathroom Renovation Plumbing Take?
The plumbing work in a typical bathroom renovation takes between 5 and 10 days, depending on the complexity of the job.
Like-for-like replacement (no layout changes): 3-5 days for the plumbing work specifically. The whole renovation might take a week or two when you include tiling, decorating, and other trades.
Layout changes: 5-8 days for plumbing. Moving the toilet or repositioning the bath takes longer because new pipe runs need to be installed.
Adding a new bathroom or en-suite: 7-14 days for plumbing. New pipework needs to be run from existing supply points, often through walls or under floors.
Wet room conversion: 8-12 days for plumbing. Wet rooms need careful waste positioning and proper tanking, which adds time to the plumbing stages.
These are working days for the plumber. The total renovation typically takes 2-3 weeks once you add tiling, painting, and other finishing work.
Planning Your Bathroom Renovation
A well-planned bathroom renovation runs smoothly. A poorly-planned one becomes a nightmare. Here’s how to plan properly.
Step 1: Decide What You Want
Before you talk to plumbers, work out what you want from your new bathroom:
- Bath, shower, or both?
- Walk-in shower or over-bath shower?
- Wet room or traditional enclosure?
- Existing layout or moving things around?
- Standard fittings or designer pieces?
- What’s your priority: style, function, or budget?
The clearer you are about what you want, the easier it is to get accurate quotes.
Step 2: Survey Your Existing System
Get a plumber to assess what you’ve already got before you finalise plans. Things they’ll look at:
- Condition of existing pipework
- Water pressure (some power showers need higher pressure than older systems provide)
- Boiler capacity (a second bathroom might require a system upgrade)
- Floor structure (heavy baths and wet rooms need adequate support)
- Existing waste runs and soil pipe positioning
This survey often reveals constraints or opportunities you weren’t aware of.
Step 3: Get Detailed Quotes
A proper quote should include:
- Strip-out and disposal of existing bathroom
- All plumbing labour (first fix and second fix)
- All plumbing materials and fittings
- Pressure testing and commissioning
- Making good around new pipework
Quotes that are vague or significantly cheaper than others usually mean things are being left out. Ask for an itemised breakdown.
Step 4: Plan the Order of Work
Bathroom renovations involve multiple trades that need to work in the right order:
- Strip-out (1-2 days)
- First fix plumbing (2-3 days)
- First fix electrical (1 day)
- Plastering and making good (1-2 days)
- Tiling (3-5 days, including curing time)
- Second fix plumbing (1-2 days)
- Second fix electrical (1 day)
- Painting and decorating (1-2 days)
- Final fix and snagging (1 day)
A good plumber can coordinate with your other trades or recommend ones they’ve worked with before.
Step 5: Arrange Alternative Bathroom Facilities
Your bathroom will be unusable for 2-3 weeks. Plan for this:
- Use a second bathroom if you have one
- Arrange with friends or family
- Consider a gym membership for showers
- Camping toilet for emergencies
Don’t underestimate how disruptive being without a bathroom is. Plan it for a time when you can cope with the inconvenience.
How to Make Your Project Run Smoothly
Bathroom renovations can get complicated quickly. Here’s how to keep yours on track.
Keep the existing layout if possible. Moving the toilet is the most complex change you can make because it involves the soil pipe. Keeping fixtures in their current positions saves significant time and disruption.
Don’t over-spec the suite. A mid-range Roca or Ideal Standard suite gives you most of the quality of premium brands without the markup. Quality matters where it shows and where it gets used.
Plan around your existing pipework. If your existing shower is well-positioned and works fine, keep it where it is. Use the saved time on better fittings or finishes you’ll notice every day.
Consider tile size and pattern. Large-format tiles are quicker to lay than mosaics. Plain tiles are quicker than patterned ones. Both reduce installation time without much impact on the finished look.
Get three quotes minimum. Quotes vary significantly between plumbers. The cheapest isn’t always best, but neither is the most expensive. Three quotes shows you which plumber has planned the work most thoroughly.
Common Bathroom Plumbing Mistakes to Avoid
Even well-planned bathroom renovations can go wrong. Here are the most common plumbing-related mistakes.
Ignoring water pressure. That stunning rain shower head needs proper water pressure to work. Check your pressure before you buy fittings, or you’ll be disappointed when your shower trickles.
Skimping on the extractor fan. Bathrooms need proper ventilation. Cheap fans don’t move enough air and lead to damp and mould problems. Spend a bit more on a humidistat-controlled fan.
Wrong soil pipe positioning for the new toilet. If you’re moving the toilet more than a metre or two, you’ll need significant pipework changes. Talk to your plumber before committing to a new layout.
Forgetting about isolation valves. Without isolation valves on each fixture, you have to turn off the entire bathroom water supply for any future maintenance. They cost almost nothing to fit during installation but are expensive to retrofit.
Choosing fittings before consulting the plumber. That beautiful designer tap might not be compatible with your existing pipework or water pressure. Confirm compatibility before you order.
Inadequate waterproofing in wet rooms. Wet rooms need proper tanking. Cutting corners here causes leaks that damage the room below within months.
Using the wrong pipe materials. Modern push-fit fittings are great for accessibility, but compression and soldered joints are more reliable for hidden pipework. The right choice depends on the application.
Things to Consider If You’re in London
If you’re renovating a bathroom in London, there are some specific factors that affect the work.
Period Properties
Victorian, Edwardian, and 1930s properties present unique challenges:
- Existing pipework may be at the end of its life and need replacing
- Floor structures might not support modern fixtures (cast iron baths, heavy stone tiles)
- Original features (cornicing, sash windows) may need protecting during work
- Layouts often need adapting to fit modern bathroom expectations
Plan for the unexpected when working on older properties.
Hard Water
London’s hard water affects bathroom installations:
- Limescale builds up rapidly in showers, taps, and toilet cisterns
- Mixer valves and thermostatic showers need scale protection
- Tile grout and silicone need regular cleaning to prevent limescale damage
Consider a water softener or scale inhibitor as part of your renovation. It protects your investment and reduces maintenance.
Flats and Conversions
Bathroom renovations in flats bring additional considerations:
- Building management approval often required
- Working hours may be restricted
- Soil pipes might be shared with other flats
- Sound insulation needs to be considered to avoid disturbing neighbours
Check your lease and speak to your building management before finalising plans.
Boiler Capacity
A bathroom renovation often pushes existing boilers to their limit. If you’re adding a second bathroom, fitting a power shower, or moving from a single shower to a multi-head setup, your existing boiler might not cope.
Have your boiler assessed alongside the bathroom plan. It’s better to upgrade now than to discover six months later that your new bathroom doesn’t have enough hot water.
How Aren Heating & Plumbing Can Help
At Aren Heating & Plumbing, we do not provide full bathroom renovation or refurbishment services. We do not manage bathroom projects, carry out full strip-outs, tiling, decorating, electrical work, or general building work.
However, if you are planning a bathroom renovation and require specific plumbing work as part of the project, we may be able to help.
Our role is focused on the plumbing side only. This can include tasks such as altering pipework, replacing or relocating radiators, fitting or replacing taps, connecting sanitaryware, resolving water pressure issues, repairing leaks, or carrying out other clearly defined plumbing work required during a bathroom project.
If you already have a bathroom fitter, builder, or renovation company in place, we can work alongside them where appropriate to complete agreed plumbing works. We are also happy to advise honestly if a particular request falls outside the type of work we carry out.
What We Do Not Provide
To avoid any confusion, Aren Heating & Plumbing does not usually provide:
Full bathroom refurbishment services
Bathroom design or project management
Full strip-out and disposal of old bathroom suites
Tiling, decorating, plastering, carpentry, or electrical work
Complete first and second fix bathroom installation packages
Wet room installation or waterproofing/tanking systems
Bathroom renovation surveys where we are not carrying out the plumbing work
When to Contact Us
You may wish to contact us if you have a specific plumbing issue or plumbing requirement connected to a bathroom renovation.
For example, this might include moving pipework before a new suite is fitted, replacing faulty valves or taps, improving water flow, dealing with leaks, replacing radiators, or checking whether your existing plumbing is suitable for a planned change.
Call Aren Heating & Plumbing on 0203 807 5822 or visit arenheatingplumbing.co.uk to discuss the plumbing work required.
We will always be clear about what we can help with, what falls outside our service, and whether your project is better suited to a bathroom renovation specialist.
