How much does it cost per square foot to add to a home in seattle?

We are in the process of adding a master bath in Michigan. Kids are all grown and we're going upscale (granite, glass block shower, tile, heated floor, jacqucci) Our cost is $250 per sq ft. We could've done a nice bath (17'x8') for $150 per sq ft. good luck!

some houses lend themselves easily to a remodel, IE... just tear out a chunk of roof, put 2 x 12 joist next to the 2 x 6's, deck it & frame away......others have lots of plumbing & wiring in the way all having to be moved......You should do a very complete study of the area that you are digging into , to determine whether it's worth the ride....