Bathroom flooring and plasterboard repair

For UK homeowners, addressing these issues simultaneously ensures the room remains watertight and structurally sound. Proper remediation prevents the growth of mould behind tiles and protects the wooden joists that support your home's integrity.

What Does the Work Involve?

• Site Assessment: Inspecting the subfloor and wall studs for rot, damp, or structural compromise.
• Strip-out: Removing damaged floor finishes, sodden underlay, and "blown" or mouldy plasterboard.
• Structural Repair: Reinforcing or replacing water-damaged floor joists or timber stud work if required.
• Boarding: Installing moisture-resistant (green) plasterboard and taping joints to ensure a vapour-tight seal.
• Subfloor Preparation: Levelling the floor using marine-grade plywood or self-levelling compound to create a flat surface.
• Finishing: Applying a multi-finish skim coat to walls and installing bathroom-grade flooring (LVT, vinyl, or tiles).
• Waste Management: Safe removal of old materials and debris in accordance with UK environmental regulations.

Typical Costs

Prices vary depending on the extent of the water damage and the quality of the replacement flooring chosen. Expect to pay more in London and the South East due to higher labour rates.

Factors such as the need to remove and reinstall sanitaryware (toilets, basins) or the discovery of asbestos in older textured coatings will significantly increase the final invoice.

How Long Does It Take?

• Minor repairs: 1–2 days (Patching a small area of wall and laying sheet vinyl).
• Standard bathroom overhaul: 3–5 days (Including drying time for plaster skim and floor levelling compounds).
• Complex structural work: 5–8 days (If floor joists need sistering or if extensive plumbing relocation is required).

DIY or Professional?

While a confident DIYer can lay click-lock flooring, plastering and structural repairs are best left to professionals. Achieving a "flat" wall and a perfectly level floor is harder than it looks, and mistakes lead to pooling water or cracked tiles.

Any work involving the removal of radiators or sanitaryware should be handled by a professional to avoid flooding, and electrical work must comply with Part P of the Building Regulations.

Choosing the Right Tradesperson

• Look for specialists in "Bathroom Fit-outs" or "Property Maintenance" who understand both carpentry and wet-room prep.
• Verify they carry Public Liability Insurance (minimum £1m-£2m).
• Ask if they are comfortable working with moisture-resistant systems like Schlüter or HardieBacker rather than standard plasterboard.

Questions to ask:

• "Do you use moisture-resistant 'green' board as standard for bathroom repairs?"
• "Is waste disposal included in your quote, and are you a registered waste carrier?"
• "How long must I wait for the plaster/screed to dry before the flooring can be laid?"
• "Can you provide references or photos of recent bathroom remediation work?"

UK Regulations

• Part P (Electrical Safety): If the repair involves moving sockets or lights near "zones" (bath/shower), it must be certified.
• Part M (Access): Ensure repairs don't create significant lips or trips that impede accessibility.
• Building Regulations: Structural repairs to floor joists may technically require notification to Local Authority Building Control.
• Asbestos: Homes built before 2000 may have asbestos in floor tiles or "Artex" ceilings; these must be tested before disturbance.

Common Problems

• Trapped Moisture: Laying new flooring over a damp subfloor will cause the new material to warp or lift within months.
• Incorrect Plasterboard: Using standard grey plasterboard in a splash zone leads to "wicking," where water travels up the wall.
• Uneven Subfloors: Skipping the self-levelling compound step often results in "bouncing" LVT or cracking grout lines in tiles.
• Sealant Failure: Failing to use high-quality silicone at the junction between the new floor and the repaired wall.

Frequently Asked Questions

Can I just plaster over damp-damaged boards?

No. If the core of the plasterboard has been wet, it loses structural integrity and will likely harbour mould. It must be cut out and replaced with moisture-resistant board.

What is the best flooring for a bathroom repair?

Luxury Vinyl Tile (LVT) or high-quality sheet vinyl are excellent as they are 100% waterproof. Tiles are durable but require a perfectly rigid subfloor to prevent grout cracking.

Do I need a plumber as well as a floor layer?

Usually, yes. To repair the floor properly, the toilet and basin often need to be removed. A multi-skilled tradesperson may do both, but check this beforehand.

Why is my new plaster turning pink/brown?

This is usually "bleed-through" from old water stains or soot. A stain-blocking primer should be applied to the repaired area before final painting.

How do I know if my floor joists are rotten?

If the floor feels "spongy" or has a noticeable dip, the timber underneath may be compromised. A professional will check for "soft" spots using a probe once the floor finish is removed.