Time for an addition! Or if you have an unfinished basement, that makes a great place to expand into. Some attics have enough head height for useable space there.

Otherwise, do what so many of your neighbors have done; add a partial second floor, or convert a garage into living space. Typically, garages are not insulated or heated, so this will require more work than at first it might seem, since the walls and roof are there!

As a last resort, expanding outward into the yard will add square feet to a home. There are many options! We have many years experience and can advise you on the Bellingham home additionbuilding codes.