Asbestos was historically added to window putty as reinforcement to increase its strength and durability and to improve its fire resistance properties. Enhanced fire resistance for putty was a valuable property as it protected the surfaces it was applied on from heat damage.
The asbestos fibres in putty do not become airborne easily as they are bound within the material, as such the risk of exposure is negligible if undisturbed and even during activities like cleaning and painting. While this material is considered non-friable and low risk, putty on windows that have been constantly exposed to the elements over a time span of years will eventually break down. This weathering of the putty can cause it release fibres more easily and become friable, therefore caution is advised when disturbing old windows.
As with all ACMs, asbestos containing putty poses the greatest risk when it is disturbed with the risk increasing with the level of force applied. For example, using a knife or chisel to remove window putty will have a lower risk of releasing fibres than using an abrasive power tool to grind the material.
If you are unsure about a material in your home or workplace and plan to disturb it you can send in a sample
for analysis or request one of our samplers to come out to the property and collect a sample for you.