Light brown is usually a glue with no fibers at all. Darker glue is more likely to have it. However, the material MUST be tested to be 100% sure either way. There are no absolutes either way.
Thanks for the responses. My instinct when I saw it was that it was a glue but I have no experience in construction materials.
About 10 years ago, I removed some wood parquet flooring squares in a home built around 1979. I did not wear a mask or goggles and recently became aware of the threat of asbestos in older homes. The adhesive that bound the parquet to the concrete foundation of the house was so strong that I had to use one of those little hand jackhammer like tools to pry the parquet up. Often the parquet would break or the the concrete would break off because the adhesive was so incredibly strong. To me the adhesive looked light brownish in color and if I remember correctly sort of had a semi-transparent look. It did not look like black mastic. I have heard some people say that a substance called bitumen was often used at that time as adhesive and that bitumen likely contained asbestos in the 1970s. Does what I describe color wise sound like bitumen? Could it have been something else that did not contain asbestos? I am concerned for my health. I am hoping that some contractor out there might be familiar with how parquet floors were adhered in the 1970s and might be familiar with whatever this incredibly strong light brown compound might have been. It was not sticky at all and was extremely hard and strong. Thanks for any info you can provide.
