The purpose of floor concrete in this upstairs wooden condo

subfloor

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.

Photo of concrete in living room and bathroom

Best Answer

That type of subflooring, often built with "gyp-crete", a self-leveling gypsum slurry that's poured into place, is used as a sound-deadening measure. Its primary function is to dampen foot traffic and other sounds of living for the benefit of residents below. It's a common practice in budget-built hotels, apartments, etc. where pre-cast or other concrete floors aren't used.