Bathroom renovation

The short answer

A bathroom renovation typically covers a new suite, tiling, waterproofing and ventilation, and sometimes repositioning the toilet or shower, which affects drainage falls. Most bathroom work doesn't need planning permission, though building regulations cover ventilation, electrics near water, and drainage. Costs are driven mainly by tile and sanitaryware quality, whether pipework moves, and access, particularly in upper-floor tenement flats.

What the project involves

Work ranges from replacing a bath, toilet and basin like-for-like, to a full renovation with a new shower enclosure, underfloor heating, tiling and mechanical ventilation.

Wet rooms and walk-in showers need careful waterproofing (tanking) and a properly falled floor to drain water correctly, which is more involved than a standard shower tray installation.

Consents and regulations in Scotland

Building regulations govern electrical work in bathroom zones (only specific fittings are permitted near water), mechanical extraction rates, and waste pipe requirements. Most straightforward refits don't need a building warrant, but repositioning drainage substantially, or adding a bathroom where none existed, can trigger one.

In a tenement, altering shared soil stacks or drainage that other flats connect to usually needs coordination with, or consent from, neighbouring owners.

Sequencing

Strip-out, first-fix plumbing and electrics, waterproofing/tanking where relevant, tiling, sanitaryware installation, then final electrical and plumbing testing.

What commonly goes wrong

Poor waterproofing beneath tiling leading to leaks into the room or flat below, extraction fans that don't meet the required air-change rate, and underestimating how long tile adhesive and grout need to cure before a shower is used.

What it usually costs

Indicative ranges only, to help you judge a quote. They are not an estimate for your property — only the business doing the work can give you that.

• Like-for-like suite replacement: driven by sanitaryware and tile choice rather than labour complexity.
• Wet room conversion: adds cost for tanking, floor build-up and a falled drainage outlet.
• Moving the toilet or shower position: adds plumbing and sometimes floor joist work to route new waste pipework.
• Underfloor heating: a moderate addition to cost but affects floor build-up height, relevant in older flats with limited headroom.
• Extraction and electrics: adds a modest but necessary cost to meet building regulations in the bathroom zone.

What to do, in order

1. 1Decide whether the layout is changing or being kept the same, since this affects plumbing complexity.
2. 2Check whether waste pipe or soil stack changes need neighbour coordination in a tenement.
3. 3Complete first-fix plumbing and electrics before any tiling begins.
4. 4Tank wet areas thoroughly and allow proper curing time before tiling.
5. 5Fit sanitaryware and test for leaks before final decoration.
6. 6Get electrical work near water certified by a registered electrician.

Local detail for the Lothians

• Many Edinburgh tenement bathrooms were originally converted from box rooms, so waste pipe routes can be long and awkward, which affects both cost and how much reconfiguration is realistic.
• In listed New Town properties, replacing an original cast-iron bath or period fittings may be a consideration for owners concerned about character, even though it is not usually a consent issue in itself.
• Coastal East Lothian properties can see faster corrosion of bathroom extractor fan housings and fixings, so more durable external ventilation terminals are often worth specifying.
• New-build homes across West Lothian tend to have more standardised bathroom pipework, which usually makes reconfiguration straightforward compared with older stock.

When you need a professional

A Gas Safe registered engineer is needed for any gas combi-boiler work in an en suite cupboard, and a plumber experienced in tenement drainage should assess any shared soil stack changes.

Common questions

Do I need planning permission for a new bathroom?

Not for a normal internal refit. Adding a bathroom in a new location, or significant drainage changes, can occasionally require a building warrant.

Can I convert a bath to a wet room in a flat?

Often yes, but it depends on floor build-up, structural floor depth and drainage fall available, which a tradesperson should assess before committing to the design.

Related pages

• Kitchen renovation

  Replanning layout, units, worktops and services in the room most homes are refitted around.

• Loft conversion

  Turning roof space into usable rooms, from a simple rooflight loft to a full dormer conversion.