Simple economics, supply and demand. 

I recently had an estimate of $20,000 to create a basement egress window and I put my foot down and told my GC that I was going to rent the excavator, and we found much cheaper supplies, and were doing the project ourselves.

I know that I can write my travel, supplies, and food expenses off of my taxes while on that trip.

What about repairs, supplies, and other expenses?

In others experience is this return worth the risk given Multi-family environment ie supply, interest rates, project specific risks, illiquidity risk, and more specifically the Preferred Equity subordinated tranche risk (this sounds like just a Mezzanine loan without recourse).

@James Hamling thoughts on supply vs. demand and rate lock-in? 

I am curious about any potential barriers to look out for- timing, access/cost supplies, labor force?

Your returns in investing ultimately come from exchanging terminally abundant goods (fiat dollars, debt/future fiat dollars) for terminally scarce goods (high quality, supply constrained real estate).Selling to go into cash isn’t of interest unless I have a short term need for that cash or am funding another purchase.

Still need to clean it with regular household cleaning supplies, keep the dehumidifier running, and try to increase some air flow if possible. 

Demand will drop, supply will increase  and those that actually want to sell their house will ultimately have to lower their price - so the theory goes.