I'd be much more concerned about things like crumbling foundations, buried underground oil tanks, weird/illegal/collapsing extensions, etc.

I also spent three years as as a loan officer until the mortgage industry collapsed in 2007.I recent years I have been in the residential and commercial remodeling business. 

Granted, built in 1875 is older than most but if it has stood this long I doubt it will collapse in the next ten years.I'd buy it if the numbers were right. 

Nice try though.... :-) Nope, the roots of the 2008 housing collapse are widely blamed on the loosening of collateral requirements for the Big 5. 

Walls that are collapsing inward should be "raising the roof", so to speak, unless it's some odd house without bird-mouth cuts.

That's probably true, but most of the area has still not entirely recovered from the Great Recession--only recently have home prices in most begun to approach 2005 levels, and those prices are still way off from 2007/right before the collapse.

If the US dollar collapses, the value of that mortgage ON PAPER is going to drop like a rock.

I know, I know - I'm insane for thinking that the economy is a ponzi scheme and could (will) collapse.

I have always been interested in real estate, but graduated college in the middle of the collapse of the housing market.

Historical PricesSource: https://www.financialsamurai.com/are-you-a-real-mi...We had the dot-com bubble in the late 90's, followed by the housing crisis (collapse) of 2008, and in my opinion the dollar is the next bubble, see Forbes article below:https://www.forbes.com/sites/kenrapoza/2015/01/26/...The reason that I do not touch equity to purchase additional property is that I have already used leverage in the first place, and pulling on equity to get 2x leverage would essentially put me farther back from my ultimate goal of paying off the mortgages entirely to realize the full rents as passive income within 15-20 years.