In a window renovation, asbestos is typically found in glazing putty, in the sealants and jointing compounds between the frame and the wall, and in window sill boards. If the windows were installed before 1994, these materials must be examined before the windows are removed or restored. A survey is needed both when replacing windows in a detached house and in a housing company’s window renovation.
Do you need an asbestos survey to replace windows?
Yes, if the windows or the structures around them date from before 1994. When a window is replaced, the frame is pulled out of the wall and the compounds, seals and boards around it break. Finland’s Asbestos Act (684/2015) and Government Decree 798/2015 require asbestos to be investigated before this kind of work. Even just removing old putty when restoring windows is work that can release any asbestos present.
Where in a window can asbestos be found?
Glazing putty
The putty that holds the glass in the sash is a common material to test in old windows. It hardens over the years and crumbles when scraped or heated off. Restoration removes a lot of putty, so it is worth knowing what it contains before you start.
Sealants and jointing compounds
The joint between the frame and the wall is often sealed with an elastic compound. In precast concrete buildings, similar compounds are also found in the facade panel joints next to the windows. Old sealants can contain asbestos and other hazardous substances such as PCBs. That is why a hazardous substances survey is worth considering for larger window and facade projects.
Window sill boards
Thin, hard boards were often used as interior window sills in the 1960s to 1980s, and some of them are asbestos cement. On the outside, similar boards may sit under the windows instead of, or beneath, the metal flashing. The window sill is almost always removed when windows are replaced.
Other surrounding structures
Filler, render or reveal boards around the frame may also have to be opened up. The surveyor assesses on site which surfaces the window replacement will actually break and samples those.
Restoration or replacement: does it change what you need?
Many people want to keep and restore their old timber windows. In restoration the window is not taken out of the wall, but old putty is removed, the glass comes out and surfaces are scraped. So the putty is worth testing in a restoration too. In a replacement, the whole frame comes out, which also brings in the sealants, sills and surrounding surfaces. The scope of the survey therefore depends on what is actually being done to the window and its surroundings.
Detached house or housing company: who orders the survey?
Detached house
In a detached house the owner orders the survey before the window contractor starts. It pays to do it at the quotation stage so the contractor can include any asbestos removal in the price and schedule. If all the windows are being replaced, one survey is usually enough when the windows and the way they were fitted are the same. If the structures differ, samples are taken from different window types and different sides of the facade.
Housing company
In blocks of flats and terraced houses the windows are usually the housing company’s maintenance responsibility, so the window renovation is the company’s project and the company commissions the survey. It covers a representative selection of window types and facades. As a shareholder it is still good to know that the surveyor needs access to the flats to sample interior sills and frames. Read more about asbestos surveys in housing companies.
How a window renovation proceeds when it comes to asbestos
- Find out when the windows were installed and whether they have been replaced before.
- Order the survey before asking for contractor quotes.
- The report is usually ready within 1 working day of the visit.
- If asbestos is found, an authorised removal contractor removes the asbestos-containing parts before installation, or the window contractor includes the asbestos removal in the contract.
- Once the asbestos-containing parts are gone, the new windows are installed as normal.
How much does a survey cost?
Depending on the city, an asbestos survey costs from 119 € incl. VAT. The price includes the survey, all samples, the laboratory analysis, travel and the report. Samples are analysed with a JEOL SEM-EDS electron microscope. See the price for your city in the price list. If you only want to check one material, such as a window sill board, you can send a sample by post for 39,90 € + VAT per sample.
Checklist before replacing windows
- Materials to test: glazing putty, sealants and jointing compounds, window sill boards and surrounding surfaces.
- Order the survey before the contractor quotes, not on demolition day.
- In a housing company, the company usually orders the survey. Make sure the surveyor can get into the flats.
- Sealants can contain PCBs as well as asbestos, so consider a hazardous substances survey for a larger project.
Buying an older house whose windows will soon need replacing? Read about asbestos surveys when buying a house or order an asbestos survey.