Tar off-gassing

Q: I own a 1954 home in Houston with wood floors. I was told that the slabs on homes in Houston were covered with tar in areas over which wooden floors were to be laid, with the tar acting as a moisture barrier and anchor for the runner / supports. The person who told me was adamant that it was common and done on most, if not all, homes here in that time.

My research found references to a solid layer of tar only on conjunction with block or parquet floors.

Do you have any idea how prevalent that practice of coating all slab areas under wood floors with a layer of tar was in Houston in the early 50s, as opposed to tar paper or just a strip under the runners?

I imagine after 53 years that the off-gassing would be negligible, but I still would like to know.

A: This tar was also used for parquet block here in Toronto, but as to the situation in Houston in the early 1950’s, I wouldn’t know….

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