If your home was built before 1980, the putty holding your window glass in place may contain asbestos — and that matters most when you are planning to replace or repair those windows. Here is what you need to know to keep your family safe.
What Is Asbestos Window Glazing?
Window glazing is the compound — sometimes called window caulk or glazing compound — that seals glass panes into their frames. Along with related materials like wiring insulation and similar products, this compound can contain asbestos in older homes and should always be screened, treated, and disposed of properly.
You may already know from following the ES America blog that asbestos turns up in many places in older homes — in walls, under linoleum and carpet, in or behind heating appliances, in toilet cisterns and seats, in meter boxes. But did you know your windows could be another source? Asbestos was often added to the putty used to seal window panes, particularly in homes built in the early and middle decades of the twentieth century.
Why Was Asbestos Used in Window Putty?
It may seem like an odd choice, but asbestos was valued in construction for the same reasons it appeared everywhere: it added strength and fire resistance. Fire resistance is especially desirable in window putty.
Some putties are intumescent, meaning they swell when heated, increasing in volume while decreasing in density. This makes them highly effective at protecting surfaces from heat damage — and asbestos was most likely present in those varieties. (Asbestos-containing putty was also widely used in US naval warships, which tells you how valued those fire-resistant properties were.)
The intentions behind using asbestos were good. The problem is that old windows are now just another potential source of asbestos exposure — especially during renovation or window replacement.
When Does Window Glazing Become a Health Risk?
The risk grows over time as the putty weathers and starts to degrade. Anyone who has spent a winter in an older, unrenovated home knows this scenario: the putty around the windows wears down until it no longer keeps the cold out. Many people use temporary fixes like insulating tape in the meantime — but the putty keeps breaking down, becoming friable (crumbly), and posing the risk of asbestos fibers being released into the air you breathe.
Before you replace or repair old windows, please make sure the putty does not contain asbestos first.
How Does ES America Handle Asbestos Window Glazing?
As a licensed asbestos abatement contractor, ES America follows all EPA (Environmental Protection Agency) protocols and regulations to safely remove:
- Window caulk
- Glazing compound
- Wiring and similar materials
For more information on asbestos regulations and health guidance, visit the EPA Asbestos resource page.
Have questions about window glazing in your home? We are here to help. Reach out to our team at services@es-america.com for a free consultation.