Bathroom Renovation London: Planning, Costs and Finding Contractors

Planning Stage: Establishing the Foundation

The order in which you make decisions at the planning stage has a significant effect on how well the project goes. The single most common mistake in bathroom renovation planning is choosing contractors before choosing fittings — which means the contractor cannot provide an accurate quote, and the pricing agreed before tile and fixture selection is inevitably revised upward when the actual products are known.

Step 1: Establish a Realistic Budget

Before choosing anything else, set a budget range with a hard upper limit. London bathroom renovation costs span a very wide range — from a basic refresh at £2,000 to a premium full renovation exceeding £15,000. The primary determinant of where in this range your project falls is your choice of fittings and tiles — the labour component is more predictable than the material cost.

A useful starting framework for London 2025:

• Basic refresh (existing layout retained, mid-range fittings, ceramic tiles): £2,000–£4,000
• Mid-range full renovation (same footprint, new fittings throughout, porcelain floor and wall tiles, new shower enclosure): £4,000–£8,000
• Premium renovation (layout change possible, designer fittings, large-format stone or premium porcelain tiles, underfloor heating, bespoke cabinetry): £8,000–£15,000+

These ranges include materials and labour. They do not include structural work (if a wall needs to be moved), electrical work above basic socket and extraction changes, or building regulations costs.

Step 2: Decide on Layout

The most expensive thing you can do in a bathroom renovation is move the soil pipe connection — the 100mm waste pipe that exits the property to the drain. Once the layout decision is made, confirm whether it requires moving the toilet waste position. In a London Victorian terraced house with a solid ground floor, moving a soil pipe connection means breaking through the slab — add £500–£1,000 to the budget for that element alone. Keeping the toilet in the same position is almost always the most cost-effective decision.

Also consider shower vs bath. Removing a bath and replacing it with a walk-in shower increases the usable floor area and is popular in London where bathroom footprints are compact. This is a decision that affects waterproofing requirements, drainage position, and the tile area — make it before choosing anything else.

Step 3: Choose Fittings Before Booking Contractors

Select the toilet, basin, bath or shower tray, taps, shower valve, and tiles before approaching contractors for quotes. A contractor can only quote accurately when they know what they are installing. Provide a complete specification — product names, model numbers, sizes — to every contractor you invite to quote, so their quotes are genuinely comparable on a like-for-like basis.

What Affects Cost in London Specifically

Labour Premium

Labour rates in London are consistently 20–30% higher than the national average for all construction trades. A tiler charging £150–£200 per day in Manchester is charging £200–£280 per day for equivalent work in London. The same applies to plumbers, electricians, and plasterers. This labour premium is real and unavoidable — it is a consequence of London's cost of living affecting tradespeople's rates in the same way it affects everyone else's wages.

Floor Type

Victorian solid concrete or compacted earth floors — common in ground-floor bathrooms in London terraces — require more work than suspended timber floors. Routing a waste pipe under a solid floor means breaking the slab, cutting a channel, laying the pipe, and re-screeding. This adds £500–£800 to a ground-floor project compared to an equivalent project with a suspended timber floor. An upper-floor bathroom with a timber joist floor is significantly easier to work on for waste routing.

Access in Flats

London flats — particularly those in converted Victorian houses — present access challenges for bathroom renovation. Getting materials up narrow stairs, working in small spaces, managing waste removal through shared hallways, and connecting to soil stacks shared with other flats all add complexity. Some converting work (particularly connecting a new waste to the shared soil stack) requires negotiation with the building's managing agent or freeholder, and the managing agent may require a surveyor to inspect the proposed connection. This can add both time and cost to the planning process.

Waterproofing Requirements

Modern bathroom waterproofing — tanking the shower area and floor before tiling — is a significant improvement over older approaches. A properly tanked shower will not leak; an untanked one will eventually. However, tanking adds cost: a waterproof membrane system applied to walls and floor before tiling costs £300–£600 in materials and labour for a standard shower area. Some contractors include tanking as standard; others present it as an add-on. Always confirm that the shower area will be tanked and that the tanking system is compatible with the chosen adhesive and grout.

Trades Needed: Who Does What

A full bathroom renovation involves at least four different trades, sometimes five:

• Plumber: Rough-in (positioning waste and supply connections), disconnecting and disposing of old fittings, fitting new soil pipe connections, and fit-off (connecting the actual fittings once tiling is complete — toilet, basin, bath, shower valve, taps, waste fittings).
• Tiler: Preparing the wall and floor substrate, tanking the shower area, laying floor tiles and wall tiles to the specification.
• Electrician: Fitting the extractor fan (a Building Regulations requirement for bathrooms without openable windows), shaver socket, and any recessed ceiling lighting. Must be Part P registered for notifiable work.
• Plasterer: Often needed to repair or skim walls after stripping old tiles, or to prepare new plasterboard walls in a reconfigured layout. May not be needed in a straightforward tile-on-tile or tile-on-tanking scenario.
• Decorator: For painting any non-tiled surfaces — ceiling, window reveal, exposed wall areas.

Sequencing: The Critical Path

Getting the trade sequence wrong wastes money and time. The correct sequence is:

1. Plumber (rough-in): First into the empty stripped room. All supply pipes and waste pipes positioned correctly and capped. Soil pipe connection made.
2. Electrician (first fix): All wiring chased in, extractor fan duct installed, junction boxes and back-boxes positioned.
3. Plasterer (if required): Any wall repair or new plasterboard skim completed and fully dried. Minimum drying time: seven days for fresh plaster.
4. Waterproofing and tanking: Applied to shower area and floor after plaster is dry and before any tiles go down.
5. Tiler: Floor tiles first, then wall tiles. Allow tile adhesive and grout to cure before grouting (typically 24 hours) and before fitting plumbing fixtures (typically 48–72 hours for adhesive cure).
6. Plumber (fit-off): Returns to connect all fittings once tiling is complete and cured. Toilet, basin, bath, shower tray, shower valve, taps, waste fittings, towel rail.
7. Electrician (second fix): Connects extractor fan, fits lighting, installs shaver socket.
8. Decorator: Ceiling and remaining surfaces.

Never allow the plumber to fit-off before tiling is complete — tiling around fitted sanitary ware is significantly harder and the result is inferior. Never tile before plastering and tanking — tiles applied to unsuitable substrate fail.

Supply vs Fit vs Supply and Fit

Three purchasing models operate in the London bathroom market:

• Supply and fit: The contractor supplies all materials (fittings, tiles, adhesive) and completes all work. Simplest for the homeowner, least control over specification and product choice, typically highest overall cost per item as the contractor adds margin on materials.
• Supply only, then fit: The homeowner purchases all fittings and tiles directly; the contractor quotes labour only. Maximum control over specification and cost, but the homeowner bears all risk of incorrect ordering, delivery delays, and product defects.
• Partial supply: The homeowner supplies the sanitary ware (toilet, basin, bath) and tiles; the contractor supplies consumables (adhesive, grout, sealant, fixings). A common middle approach.

Planning Permission

A like-for-like bathroom renovation — replacing existing fittings with new ones in the same positions, within the existing room — does not require planning permission. Layout changes within the same room also generally do not require permission. Planning permission would only be required if the renovation involves creating a new bathroom in an unconverted space, or in a listed building where any internal works may need listed building consent. When in doubt, confirm with your local planning authority — it takes one phone call.

Building in the Contingency

Add a 15% contingency to any bathroom renovation budget in London. Victorian properties in particular have a habit of revealing unexpected problems once walls and floors are opened: evidence of previous water damage behind old tiles, saturated floor boards under the bath, asbestos floor tiles under linoleum, rusted cast-iron soil pipes in need of replacement. None of these are unusual and all of them add cost. A 15% contingency is not pessimism — it is realistic budgeting for London's old housing stock. If you do not spend it, it stays in your pocket.