Additionally, while rates aren't historically bad right now, they are higher than 4-5 years ago, and they will be even higher for you as an investor than they were as an owner occupant, which is what you were when you bought originally.I get that you are anxious to add to your portfolio, but that could be achieved without touching your first golden goose.Sometimes on BP, the push is to leverage every last spare penny, but that can be a risky game as the markets shift. 

Additionally, any existing restrictions at the town level (there are MANY) will be abolished, unless deemed "reasonable" by the state.

Here is a list of why adding a single ADU in single family zoned areas in my CA market is typically a poor RE investment:1) The value added by the ADU addition is often significantly less than the cost of adding the ADU.

This is the 5th Entitlement project I have funded over the last 5 or 6 years in addition I did a 60 lot one in Orlando for a developer there and a 110 lot one in the Atlanta area for a build to rent developer who then sold to Lennar for build to rent ..

Excess depreciation could be suspended as a passive loss unless you qualify as a Real Estate Professional (REPS) or materially participate in a Short-Term Rental (STR)—which would allow you to use the additional depreciation to offset W-2 or business income.

And if you join Lowe's Pros, you'll get an additional discount (it's free to join).

That leaves an additional market demand of 780 units.

Ultimately, I do think S8 requires scale and lots of efficiencies but has its benefits. 

the majority of even my national users are looking to keep cash in reserve and as such are looking to landlords to finance that TIA as additional rent at a return premium and then that extra rent bakes off in whatever term is negotiated. 

I know this is a very old thread but if anyone comes across it I wanted to add some additional thoughts that might be helpful.