Renovating a bathroom in a block of flats or a terraced house is not only the resident's own business. A wet room connects to the housing company's structures and pipework, and poorly done waterproofing can damage the neighbour's apartment as well. That is why the Limited Liability Housing Companies Act and the housing companies' own rules set conditions for the work.
This guide goes through what to do at each stage so the renovation runs without surprises.
1. The alteration notice before you start
Under the Limited Liability Housing Companies Act, a shareholder must notify the board or the property manager in writing of alteration work that may affect the company's or another shareholder's spaces. A bathroom renovation is almost always such work.
The notice states what will be done, by whom and when. The housing company may set conditions needed to prevent harm — for example, using a supervisor, inspecting the waterproofing, or restricting working hours.
2. Asbestos survey in older buildings
If the building was constructed before 1994, opening and demolishing structures must be preceded by an asbestos survey, which the party commissioning the work arranges. Asbestos can be found in tile adhesives, grout, levelling compounds and old waterproofing, for example.
If asbestos is found, removal must be carried out as asbestos removal work by a party authorised to do it. The rules on asbestos work were tightened at the turn of 2025–2026, so check the current requirements with the occupational safety authority.
3. Planning and the quote
Before asking for a quote, decide whether fixtures and water points stay where they are. Moving a drain or floor gully is always a bigger job than renewing surfaces, and it affects both the price and the housing company's conditions.
Ask for a written quote that sets out the content and schedule of the work. For the household tax credit, the labour portion must be itemised on the invoice.
4. Strip-out and checking the structures
Once stripped, the condition of the structures becomes visible. Any moisture damage must be repaired before new surfaces go on — otherwise the problem stays hidden under the new tiles.
5. Waterproofing and documentation
Waterproofing is applied with an approved system according to the manufacturer's instructions. Housing companies often require it to be inspected before tiling and an inspection record to be drawn up.
Keep the documents. They are useful when you sell the apartment, too, and the buyer asks about the condition of the wet room.
6. Tiling, installation and handover
After tiling and grouting, the fixtures and fittings are installed. Electrical and plumbing work is done by professionals qualified for it. Finally the room is cleaned, the work is walked through together, and the housing company receives the documents it requires.