mildew/basement odor

A few months after we completed a renovation of our townhouse, a mildew-basement type odor has arisen in the back garden floor bathroom and pantry (each are newly built) and a similar, but maybe more sewer-smelling odor outside in the front area on the garden floor, next to the stoop. These odors were not present prior to or during renovation. Cannot find anything in the basement that is uncapped or open, although sometimes has the same smells.

Does anyone have any suggestions about cause and remediation?