Traditional wood frame, with lumber pressure treated with a fire retardant. They might have some CLT beams, but they're predominantly built out of pressure tre

Traditional wood frame, with lumber pressure treated with a fire retardant. They might have some CLT beams, but they're predominantly built out of pressure treated lumber and plywood. They're safe because they have sprinkler systems, building-wide fire alarms and redundant fire-resistant staircases. Sound generally isn't an issue if you have polite neighbors, but if somebody upstairs is doing jumping jacks you'll definitely hear it.