a new structure attached to an existing building walls, windows, and doors roofing a chimney an entryway possibly a porch or deck other architectural features, such as columns or cornices
addition which is a new structure attached to an existing building addition which has walls, windows, and doors addition which has roofing addition which is a chimney addition which is an entryway addition which has possibly a porch or deck addition which has other architectural features, such as columns or cornices