The short answer
Plan a bathroom in this order: set a budget, fix the layout, choose fixtures, then sequence the trades. Decide what you can spend, work out whether the existing plumbing layout can stay (moving the WC and soil stack is the costliest change), select your suite and finishes, then let a bathroom installation specialist sequence strip-out, first fix, tiling and second fix. Good planning prevents the expensive mid-job changes that wreck budgets.
A bathroom renovation is one of the more disruptive home projects because so many trades work in a small, wet space in a fixed order. Planning thoroughly before any work starts is the single biggest thing you can do to keep the project on budget and on time. This guide walks through the planning steps in the order that matters, and links to the detailed cost and process guides at each stage.
Planning at a glance
- Step 1 Set a realistic budget
- Step 2 Fix the layout (keep plumbing if you can)
- Step 3 Choose suite and finishes
- Step 4 Sequence the trades
- Costliest change Moving the WC / soil stack
- Typical duration 7–12 working days
Step 1: set a realistic budget
Start with a number you are comfortable spending, then test it against reality. A budget refit typically runs £3,000–£6,000, a mid-range project £6,000–£12,000, and high-end work £12,000–£25,000 or more. Roughly half of a typical project is labour and half is materials, so a tight budget means restraint on both. Always hold back a contingency of around 10–15% for the surprises that hide behind old tiles and panels — rotten timber, dated wiring and failed waste pipes are common. Our full new bathroom cost guide breaks down where the money goes.
Step 2: fix the layout
The layout decision drives more cost than almost anything else. If you keep the WC, basin and bath or shower roughly where they are, the plumbing runs and soil connection can largely stay, which keeps labour down. Move the WC or the soil stack and you add significant drainage work. In a small room, a workable layout matters even more — see our small bathroom layout ideas. Decide early whether you want a bath, a shower, or both, using our bath vs shower guide.
| Planning decision | Cheaper choice | Costlier choice |
|---|---|---|
| Layout | Keep existing positions | Move WC / soil stack |
| Bathing | Over-bath shower | Separate bath + walk-in shower |
| Walls | Half-height tiling / panels | Full floor-to-ceiling tiling |
| Suite | Standard high-street suite | Premium / designer suite |
| Heating | Towel radiator | Underfloor heating |
Step 3: choose your suite and finishes
With the layout fixed, choose the suite (basin, WC, bath and/or shower) and the finishes — tiles, flooring, taps and storage. Order everything before work starts so the installer is never waiting on a delivery; a missing item can stall a job for days. Our bathroom suites guide explains the options, tiling costs covers wall and floor tiling, and shower types and cost helps you choose a shower.
Step 4: sequence the trades
Bathrooms are built in a strict order: strip-out, then first fix (plumbing and electrical pipework and cables in the walls and floor), then plastering and tanking where needed, then tiling, then second fix (fitting the suite, taps, shower and electrics), and finally sealing and snagging. A bathroom installation specialist coordinates the plumber, tiler, electrician and plasterer so each arrives at the right moment. Our how long it takes guide and what to expect guide walk through the day-by-day flow, and labour costs covers the trades.
Common planning mistakes to avoid
The expensive mistakes are nearly always planning failures: changing your mind mid-job, underestimating the budget, ignoring ventilation, and skimping on waterproofing. Building Regulations also apply — electrical work is notifiable under Part P and mechanical extract ventilation is required under Part F. Our mistakes to avoid guide, ventilation guide and building regulations guide cover these. This page is general information; your project depends on your home, choices and chosen specialist.
Compare bathroom quotes
Once your plan is clear, use our service to compare itemised quotes from a bathroom installation specialist.
Frequently asked questions
What is the first step in planning a bathroom?
Set a realistic budget first, then fix the layout. The budget shapes every later decision, and the layout — especially whether the WC and soil stack move — drives much of the cost. With those two settled, choosing fixtures and sequencing trades becomes straightforward.
Should I keep the existing bathroom layout?
Keeping the suite roughly where it is keeps plumbing and drainage runs short, which keeps labour down. Moving the WC or soil stack adds the most cost, so only relocate fixtures if the new layout genuinely improves how the room works.
When should I buy the suite and tiles?
Before any work starts. Having every item on site before strip-out begins prevents the installer waiting on deliveries, which is a common cause of delays and extra cost. Confirm finishes and quantities at the planning stage.
Do I need to plan around Building Regulations?
Yes. Electrical work in a bathroom is notifiable under Part P, mechanical extract ventilation is required under Part F, and drainage must comply with Parts G and H. Plan ventilation and electrics in from the start rather than retrofitting them.
Sources & further reading
- KBSA — consumer guidance on planning a bathroom project
- CIPHE — plumbing and installation standards
- GOV.UK / Building Regulations Approved Documents P, F, G and H
- TrustMark — finding a vetted tradesperson for home improvement work
This is general information, not advice for your specific property or installation. Costs, timescales and outcomes vary with your home and chosen specialist. Bathroom Answers is an independent information and introduction service, not an installer.