Bathroom Renovations

A Bathroom That Actually Works

A bathroom renovation isn't just about new tiles and a fresh suite. It's about fixing the problems you've been living with — the shower that dribbles, the cold floor at 6am, the toilet that's too close to the wall, the mould in the grout that keeps coming back no matter how much you scrub. A proper renovation addresses all of it: plumbing, ventilation, waterproofing, layout, and finish.

We renovate bathrooms across the UK, from compact en-suites in London flats to family bathrooms in Manchester semis and luxury wet rooms in Bristol townhouses. Every project is different, but the approach is the same — strip it back, fix what's behind the walls, and build it right so it lasts 15–20 years without issues.

The most expensive bathroom renovation is the one you do twice. We see it regularly — homeowners who hired a general handyman, skipped the waterproofing, and ended up with water damage to the ceiling below within two years. Our bathroom builds are properly tanked, properly ventilated, and signed off where building regulations apply. We do it once, we do it properly.

What Makes a Good Bathroom?

Three things: layout, waterproofing, and ventilation. Get those right and everything else follows.

Layout is about making every centimetre count. A well-planned 4m² bathroom feels spacious. A badly planned 8m² bathroom feels cramped. We work through the layout with you — where the door swings, where the towel rail goes, how much clearance you have in front of the WC, whether the shower screen opens the right way. These details matter more than the tile you choose.

Waterproofing is what separates a professional job from a DIY disaster. Every shower area, every wet room floor, every bath surround needs proper tanking — liquid membrane or sheet membrane applied to the substrate before any tiles go on. Water finds gaps. If it gets behind the tiles, it rots the wall, stains the ceiling below, and you're ripping it all out again in three years.

Ventilation prevents mould. Approved Document Part F requires mechanical extract ventilation in bathrooms — a minimum extraction rate of 15 litres per second for a bathroom, 6 l/s for a WC. If there's no opening window, the fan must run on a humidistat or overrun timer. We install quiet, efficient fans as standard and make sure the ducting runs to the outside, not into the loft space (a common bodge that causes condensation problems in the roof).

Waterproofing & Tanking

Tanking is the process of creating a waterproof barrier between the tile surface and the substrate (plasterboard, cement board, or masonry). Water will eventually get through grout joints — it's not a matter of if, it's when. The tanking membrane behind the tiles is what actually keeps your house dry.

For standard shower areas, we apply a two-coat liquid tanking membrane (products like BAL Tank-It, Mapei Mapelastic, or Schlüter DITRA) to the walls and floor of the shower zone. Each coat is applied with a roller and reinforcing tape at joints and corners. Total thickness is 1–2mm, but it provides a continuous, flexible waterproof barrier.

For wet rooms, tanking is more extensive. The entire floor is tanked with a sheet membrane or liquid-applied system, taken up the walls to a minimum height of 150mm (we go full height on shower walls). The membrane must integrate with the drain unit to create a seamless waterproof envelope. We use systems from Impey, Schlüter, or Marmox that come with manufacturer warranties of 10+ years when installed to their specifications.

Common tanking mistakes we see on remedial jobs: using standard plasterboard in the shower zone (it disintegrates when wet), not taping joints in the membrane, and running the membrane under the shower tray instead of around it. We use moisture-resistant boards (cement board or tile backer board) behind all tiled areas, not just the shower zone.

Underfloor Heating Options

Underfloor heating in a bathroom is a genuine comfort upgrade, not a luxury. Cold tiles underfoot at 6am are miserable. There are two options:

Electric mat systems (£400–£800 installed): A thin heating mat (typically 3mm) laid on top of the subfloor, embedded in the tile adhesive. Powered by a dedicated circuit with a thermostat (usually a programmable type set to warm up 30 minutes before your alarm). Running costs are modest — a 3m² bathroom mat draws about 150W, costing roughly 4p per hour at current electricity prices. Ideal for renovations because the mat adds minimal height to the floor build-up.

Wet underfloor heating (£1,200–£2,500 installed): Warm water pipes embedded in a screed or routed through the floor joists. More efficient than electric but significantly more disruptive to install — the floor needs to be raised by 50–75mm for the screed, or the joists need routing (which affects their structural capacity). Only practical if you're already fitting wet underfloor heating throughout the house, or if the bathroom is part of a new build where the floor is being laid from scratch.

Soil Stacks & Waste Plumbing

The soil stack is the 110mm vertical pipe that carries waste from WCs to the underground drainage. Its location dictates your bathroom layout more than anything else. Moving a WC more than about 1.5m from the stack requires extending the waste pipe, which must fall at a gradient of 1:40 (18mm per metre minimum). Over longer distances, this gradient can mean the waste pipe drops below floor level, requiring either a raised floor or routing through the ceiling of the room below.

Relocating the soil stack itself is a major piece of work: £800–£2,000 depending on the route. It involves cutting into the existing stack, running new 110mm pipework to the new position, and reconnecting all branch pipes (basin, bath, shower) to the new route. If the stack vents through the roof, the roof penetration needs moving too. We always exhaust every layout option that avoids moving the stack before recommending it.

Basin and shower waste pipes (40mm) are much easier to reroute. They run at a gradient of 18–90mm per metre and can often be concealed within the floor void or a stud wall. If you're on a concrete slab with no floor void, waste pipes either run along the wall surface (boxed in) or need to be chased into the slab — which is doable but adds cost (£300–£600 per route).

Ventilation Requirements

Mould in bathrooms is almost always a ventilation problem, not a heating problem. Approved Document Part F sets the requirements:

Bathrooms with opening windows: Intermittent extract fan rated at 15 l/s minimum, with a 15-minute overrun timer after the light is switched off. The window provides purge ventilation; the fan handles the moisture while the room is in use.

Bathrooms without opening windows (internal): Continuous extract at a trickle rate (8 l/s minimum) or intermittent extract at 15 l/s with a humidistat that keeps the fan running until humidity drops. A humidistat-controlled fan is the gold standard — it responds to actual moisture levels rather than a simple timer.

Ducting: Must run to the outside — through an external wall or up through the roof. We use rigid or semi-rigid ducting (never flexible foil, which sags, collects condensation, and restricts airflow). The duct should be insulated where it runs through cold spaces (loft) to prevent condensation forming inside the duct. A backdraught shutter at the external termination prevents cold air blowing back into the bathroom.

Fan selection matters. Cheap axial fans push 80–100m³/h but are noisy (40+ dB). We fit centrifugal fans rated for longer duct runs (up to 3m rigid duct), which are quieter (25–30 dB) and more effective. Brands like Vent-Axia Silent Fan, Envirovent, and Greenwood are what we specify.