2Nd Floor Bump Out Addition . These items can be a challenge to extend into new. Due to their size most bump outs blend easily to the existing exterior of the home. Home Renovation Alexandria VA Ricky Can Build It Second floor from www.pinterest.com An exception to the rule is a prefabricated bathroom pod that can be added inside a building as well as an extension. Deep), the new joists can extend 29 in. If considering a bump out addition to the first floor the foundation can be a simple concrete slab or elevated over a crawl space.