I would have an engineer analyze first and do the work they recommend.

You have a personal issue- car engine blows up, so you tell your tenant that they need to pay double the rent for one month so that you can get your car fixed?

(as permitted by my engineer) My permits are good for 18months.I am working with a builder that thinks we can do the 20x24 cabins for 100k each. so that's 600k plus another 200k for site work.i think the cabins will fetch 225 a night. however lets use 125 @ 50% occupancy. that's 22k x 6.

First - I think your accountant should be providing you recommendations for cost segregation companies.It it most likely, if he/she works with real estate investors, that he/she would have a couple to recommend.Second - There are two types of cost segregation studies.Type 1 - Conducted by an engineering firm where an engineer will inspect the property.

I've worked with a client in a very similar situation, and have spoken to many inspectors/engineers/builders, etc about things like this.

I've had some blue collar ones all the way up to software engineers and everything in between. 

Then a Civil Engineer, an Appraiser to determine what having a four unit would be worth, then a loan using the evaluation.

At time of purchase I had a couple of engineers over to look at a couple of things.

I am a FORMER engineer, recently retired.  

Nobody should be surprised, we literally social-engineered this.