1 Bedroom additionHow does adding square footage to a house affect the value? If I build a 500 square foot addition to my 1200 square foot house, and I live in a neighborhood that averages $400/square foot, then will I incrase my home value by $200,000? I'm hoping simple square footage is the real driver...March 01 2010 - Redwood City00YesReport a ProblemProblemSelect oneOffensive contentIrrelevant contentSpam (pure self-promotion)OtherDetailsYour emailPlease enter a valid email address.Submit CancelContent flaggedWe will review this content. Thanks for helping make the site more useful to everyone. To learn more, read Zillow's Good Neighbor Policy.We're sorry. This service is temporarily unavailable. Please come back later and try again.