The city should already have a copy of your home's blueprints from whenever it was built. Now, it may not be completely accurate still but you could start there. You can usually get them from city hall for a small fee.

Sina, I just googled that option, thanks. It seems like a long and arduous task to get those papers from my city. Even if they have them, I have to make an in person appointment to view them on premise in the office. while on premise, I may not take photos or make copies. To have a copy made, I must (after on premise viewing) get permission to do so by the original drafters of the blueprints. The house was built in the 30s, so these people may be difficult to track down.

I'd rather just pay someone to do it afresh.

http://www2.oaklandnet.com/government/o/PBN/OurServices/Documents/index.htm