Turning a single-family into a multi family in Seattle Wa

[Luis Felix]

 My dad is selling one of his two properties in the Phinney Ridge District of Seattle. I have tried to talk him out of it, but that’s a whole other topic.  My question is, can my dad add a second unit to his single-family home? It has a Unfinished basement. And what would the permits cost? 

[Brian Hughes]

Zoning and permitting issues aside,   you  might look at the habitability standards that are specified in Seattle's recent RRIO (rental registration and inspection ordinance)  as the unit would need to comply with these.    The parameters for the inspection are pretty bare-minimum for any reasonably built and maintained unit,    but if you are looking at converting a basement with low ceilings,  uneven or dirt floors,  moisture issues, no or very small windows,  etc.   the costs involved for building a legal MIL would be a lot more if you had to correct issues like these rather than if the home had a full height basement,  modern foundation, and existing roughed in plumbing for example.

Depending on what your father (or you) want and how long the home has been owned by your father,  selling and rolling that money into something bigger could be a good move,  though on the other hand Phinney is one of the most desirable areas in the city.