How long have construction workers been laying sheet of plastic on the ground before laying the foundation?

https://en.wikipedia.org/wiki/Vapor_barrier

The plastic “vapor barrier” is there to mitigate ground moisture from wicking up through the floor slab. In theory will function quite well if installed intact and in practice is marginal at best as having been laid over yards of crushed rock with construction workers trampling over this barrier often leaves it ruptured. Plastic visqueen barriers over time will degrade and in short order will be brittle and essentially useless for the purpose of stopping moisture migration through the slab. Upgrade to a thicker mil thickness urethane composition membrane for moisture mitigation through a slab.

What they said. Hubby also recommends a moisture barrier between the slab and the sub-floor if you’re planning on installing hardwood flooring.

It’s called bisqueen and they’ve been laying it at least since I was a frame carpenter back in the mid-1970’s.

@Espiritus_Corvus the sub floor plastic is called visqueen and Bisqueen is aYouTube video.

They’ve been using it at least as far back as the mid-1960’s. I remember my dad talking about it when I was in high school.

Long time but rarely is it done right, particularly in residential construction. Usually there are too many holes that are not sealed or gaps or no overlap. It is supposed to be a barrier, not a sieve.

@Cruiser We always called it bisqueen in Florida. I never saw it spelled. Maybe our pronunciation was influenced by the ambient Spanish culture, who knows. Like Bictor Belasqeuz. This was forty years ago. I see that when I google bisqueen, visqueen is all over the net. So, I suppose bisqueen has become just another anachronism. Goddam whippersnappers are changing everything.

Thank you so very much everyone.

So, is it optional, or do municipalities in general require it?

Building Codes require it in Florida, which means that if you want financing for your house project, which is given out in stages during the building process, you must use it.

@Espiritus_Corvus You seem ver knowledgable. I see in the link @johnpowell posted (thanks @johnpowell)
“A slab-on-grade or basement floor should be poured over a cross-laminated polyethylene vapor barrier over 4 inches (10 cm) of granular fill to prevent wicking of moisture from the ground and radon gas incursion.”

I would have thought the title of the page would have been “Moisture and Radon Barrier” or something like that. I wouldn’t have found it if I didn’t use Ctrl F to find the word radon.

@Espiritus_Corvus Around here a Sawzall is called a Sawsaw. Different Strokes.