I am doing a remodel of a 1970s built upstairs condo (WA state)
Once we took off the old carpeting and vinyl flooring, it turned out that the subfloor is made from concrete. Under the subfloor is wood (it's a wooden construction).
This is in all rooms including previously carpeted areas and including the bathroom. It's also cracked in many places given the age.
Can someone tell me what is the purpose of this concrete? It seems to me like it would add unnecessary weight to a wooden structure.