To set the scene: A cost seg study breaks your property into two important categories:1250 "real" property aka the building, foundation and other long life assets.1245 property aka anything that can be accelerated such as 5, 7, or 15 year property like carpets, cabinets, or other site improvements.

Building a 4,000-square-foot, three-story duplex with a 1,000-square-foot ADU could cost about $1.83 million, including construction and permits (excluding land).

Building small units in small counts is expensive development.  

Use tools like the VA loan for house hacking and your Basic Allowance for Housing (BAH) to cover living costs while building equity.

Start building relationships with retirees who want a better return on their money.

In Japan, it's the opposite, at least for structures (land and building values are separate). 

Personally, If I could pull out a HELOC, I would use it to fix and flip which will typically make sense as you shouldnt be keeping the money out for that long and you can recycle it or pay it back and build off the capital that you got from. the flip.

Building a real estate portfolio might be attractive, but if you're crunched for time, perhaps you could do private lending in a SDIRA or get into syndications.

It is hard work but a small team can build them pretty quick.

Quentin, build your knowledge, make sure all this is done correctly.Banks rarely call the loan just because of the deed being transferred, something else triggers this, mostly because the investor decides education is not worth the money.It can be because the Insurance was not done correctly, the seller does not understand the process, the Title Company does not know what to do so they call the Bank and make a mess out of the process and a few other factors,If the investor is knowledgeable on what to say to the Bank if they call this is a fairly simple conversation to have.