Crawlspace to Basement Conversion and Possible Addition

[Zachary Lunden]

I bought a house in the Central District of Seattle last summer. Half of the footprint has a finished basement and the other half (400 sf) is a 4' crawl space. I would like to dig it out and turn it into a finished bedroom to rent out. I am also interested in adding on to the side of the house to add square footage and additional bedrooms/bath).

I am interested in doing as much of the work as I can myself (part of the reason I bought the house), but I don't exactly know how to go about getting permits and who to use for any design (arch/engineer) that might be needed in order to get the permits. Does anyone have any helpful feedback? Maybe you have done something similar and could help guide me to the path of least resistance? Or maybe you have worked with an arch/engineer that isn't going to kill my budget? I could/will do most of the designing in Revit, but I might need help figuring out my constraints. 

Thanks in advance for any advice!