Even if you do preventative things it won't keep it dry.

It's been great in years past, however, due to saturation and stricter registration/compliance requirements, bookings have really dried up here and many are converting to longer-term rentals. 

I can about promise you Statefarm will leave you high and dry!

In my situation, a professional clean up crew repaired everything and also didn't find any mold inside of walls before starting the cleanup and new flooring and dry walls were installed and it was over ten years ago.

@Josh Mac keep in mind that Zillow can be completely unaware of factors that affect value...and some of these factors might not be apparent until you see the property in-person.For instance, maybe someone added a bathroom to the house, and now it's a 3/3, but Zillow thinks it's a 3/2.  ...or maybe the house is right next to a busy road with tons of traffic noise, but the Zestimate is based on nearby houses that are on quieter residential streets  ...or the main floor beam under the house is rotted out--Zillow would never know that...In short, there are a ton of factors that can affect a property's value that Zillow might completely miss.The Zestimate can be reasonably accurate in showing a ballpark value...but, I wouldn't make life and death investing decisions based on a Zestimate...

Seems cut and dry that with limited exceptions JADU can require owner occupancy. 

Many agents will place the first applicant with the necessary funds, take their commission and leave you high & dry with a bad tenant.YOU SHOULD DO YOUR OWN SCREENINGS! 

Yesterday, I posted my standard notice on the front door advising the occupants that the place has been sold, to call me, and that if I don't hear back, I may initiate an unlawful detainer or if the place is vacant that I may change the locks, along with a copy of the deed.The property looks barely habitable (hot water heater is on the back porch (which looks like it's about to fall off its rotted post foundation), sheets of drywall and plywood out front, tons of beer cans and collection notices on the front door, and rotted siding/wood on one side of the house.

I am a first time real estate investor looking the following property : https://www.redfin.com/OR/Forest-Grove/2418-Cedar-Cir-97116/...its a pretty large duplex in Forest Grove OR,  the trick is though, its on a lot zoned for a 4 plex so I am lookinginto house hacking, converting into a triplex, then living in one unit while renting out the remaining two unitsThe left garage has been converted to living space, with a living room, half bath, a laundry room with a sink and some counters/cupboards and a bedroom, it is a part of what was an existing 3bd unitIf I were to acquire the asset, I would first attempt to convert that space into its own unit The line items as I see (be in mind, I am totally new to this) would be to >put up dry wall where the door to the rest of the house is,>add a shower to the half bathroom >install a water heater in the adjacent 3bd unit> install a kitchen in the laundry room, (stove , oven , sink, counter space)>add a shower to the half bath Assuming I can convert it to a 3plex, I could at-least cash flow on my investment after I leave My plan would be to put minimum down payment of 3.5% (FHA loan) that way I can have a decent amount of capital free to do the renovationsThe only concern is when I crunch the numbers to get my ROI, I have no idea how much its going to cost to convert the additional living space to a third unitAny experienced investors here know how I can estimate this before I try to make an offer?

The combination of hot long summers (soil dries out) and lots of moisture in winter and spring (saturates the soil) causes the ground to constantly expand and contract.Out of state investors get freaked out by foundation issues but being that its such a normal occurrence, you have a plethora of foundation companies that know how to fix them with relative ease.