Any real estate agent on your mls can look up the historical performance of multi family units in Oakland and tell you which agents are selling a lot of them or agents who have sold them near you.

I'm building a duplex and using a lower cost builder who doesn't do any of the site work. 

There's a big difference between reading books, listening to podcasts repeatedly, asking for advice on this site where the responders don't have a truly vested interest and a mentor that you're paying that has an absolute interest in your success.  

If rotted, they can also replace window sill/framing on site, etc.

Have you done a member search on this site to try and connect with lenders?

https://www.forbes.com/sites/ingowinzer/2018/09/14/25-best-markets-for-rental-property-investment/#7110f7fb7cb7

He/she would still perform the same functions as if the property were managed by a third party company, but instead, the property would be managed by a company he/she owns. 

Great that you joined the site!

Use the site to educate yourself.

Essentially what @Omar Khan is trying to explain is that the high prices are due to very high demand and the only way that the market will collapse is if the demand disappears, which I cannot see happening with our high immigration rate and while ever everyone still only wants to live in the capital citiesDon't be fooled by the media speculation and articles posted on news sites etc about the "bubble burst" and "housing crash".