In a sauna renovation, asbestos is most often found in the heat shield boards behind the heater, in fire boards on the ceiling and walls, and in the washroom’s tile adhesives, waterproofing and filler. Especially in detached houses from the 1960s to the 1980s, these materials must be examined before any panelling, benches or tiling are removed. An asbestos survey shows which structures need asbestos removal and which can be stripped out as an ordinary renovation.
Why do saunas often contain asbestos?
Asbestos was used precisely where resistance to heat and moisture was needed, and the sauna and washroom combine both. The area around the heater was protected against fire with boards in which asbestos was a common ingredient, while the washroom’s wet areas had asbestos in adhesives, fillers and bitumen-based waterproofing. Because saunas have often only been renovated on the surface, the original boards and compounds can still be in place behind new panelling.
What is tested in the sauna and washroom?
Heat shield boards behind the heater
Grey, hard fibre cement boards were often fitted behind and beside the heater. In many older saunas they are asbestos cement. The board may be visible or hidden behind a newer shield. Read more about asbestos cement boards.
Fire boards on the ceiling and walls
Fire boards were fitted to the ceiling above the heater and around the flue. Behind the panelling there may also be thin fireproof board or card that you cannot see until the panel comes off. If needed, the surveyor opens a small area of panelling to see what lies behind it.
Chimney and flue pipe penetrations
In a sauna with a wood-burning heater, the joint between the flue pipe and the chimney may contain asbestos-bearing seals, tapes or compounds, as well as protective boards around the penetration. They are easy to miss because they are small and often sooty. These are exactly the parts that come off when the heater is replaced, so they belong in the survey.
Tile adhesives and grout
The adhesives and grout in the washroom and sauna floor tiling are one of the most common sources of asbestos. Dark, bitumen-based adhesives are typical of the 1960s to 1980s.
Waterproofing
Older washrooms used bitumen coatings and membranes as waterproofing, and these may contain asbestos. They sit under the tiles and only appear during demolition, which is why they are sampled in advance.
Wall and floor filler
There is filler both on the washroom walls and under the floor tiles. It creates dust when sanded or chiselled, and asbestos in it cannot be seen with the naked eye.
What should you check before removing the panelling?
Taking down panelling feels like a harmless job, but it is exactly behind the panels that old heat shields and fireproof card tend to turn up. Before you reach for the crowbar:
- Find out when the sauna and washroom were built and whether they have been renovated before.
- Look for visible boards behind the heater or on the ceiling and take photos of them.
- Do not drill, saw or sand any board or filler until you know what it is.
- Order a survey that covers both the sauna and the washroom, since they are usually stripped out together.
If the panelling is already off and you find an unknown board behind it, leave it in place and have a sample analysed before carrying on.
The order of work in a sauna renovation
- Survey: the surveyor goes through the sauna and washroom and samples suspect materials.
- Report: results usually arrive within 1 working day of the visit.
- Asbestos removal if needed: asbestos-containing boards, adhesives and waterproofing are removed by an authorised removal contractor.
- Normal demolition and new build: once the asbestos has been removed or confirmed absent.
Since the sauna and washroom form one whole, it is also worth reading about asbestos in the bathroom.
How much does a sauna asbestos survey cost?
Depending on the city, an asbestos survey costs from 119 € incl. VAT. The price includes the survey, all samples, laboratory analysis with a JEOL SEM-EDS electron microscope, travel and the report. You can find the price for your city in the price list. If you only want to check a single board, you can also send a sample by post for 39,90 € + VAT per sample.
Summary
- Risk materials in a sauna: heater heat shields, fire boards and fireproof card, tile adhesives, waterproofing and filler.
- Original boards may be hidden behind the panelling even if the sauna looks new.
- A survey before demolition is required by law if the structures date from before 1994.
- Survey the sauna and washroom in the same visit.
A sauna renovation is often part of a bigger project. See also how to prepare for the surveyor’s visit, or order an asbestos survey.