You'll eliminate the demo cost and time, as well as some of the material cost (1/4" vs  1/2" or 5/8").

The house has had some demo n looks worse than when i bought it so no takers that will cover the loan.

On our existing property, we have 2 running units, a 2Bd 1Ba, and a 3Bd 2 Ba, and the property has potential for additional units, and I'm faced with the dilemma of if we should rehab what is there to get to 4 units, or build 6 additional units, demo 1 and rehab 1 on the property (Zoning is already figured out) to get to 9. 

My plans are to demo the back units to replace with 4 - 5 pre fab 450 sq ft ADUs.

Make sure you have enough upside.The demo has been done though.

The reason why they want to give it for free... and I am not there so I am not sure... is because of the same thing most people say when we give an offer lower than they want to hear "The land alone is worth more than that".Yeah you Oompaloompa,  sure, but tearing and demoing the house costs 30K BEFORE I will have a piece of land I can do anything constructive with.There are a lot of issues other than just  a free house...But, hey, maybe they really are just done with it.

It has no life: it is simply an expense that is necessary to do the rest of the work, so you can write off the $25,000 demo & disposal cost immediately, then depreciate the rest.I have heard some investors will break out the cost of individual materials, such as roofing nails, and say those only have a useful life of 10 years and depreciate that component at a faster rate compared to shingles, but most of my projects are too small to bother with a few hundred dollars worth of nails.

If I don't fix the retaining wall, the garage will be a hazard and may fall soon anyways, so I plan to demo it.  

Anyone who has experience in Demo and rehab or rebuilds please get a hold of me.  1 bed 1 bath, Kitchen, bath needs to be redone, rip up the carpet and put down a floating floor.  

I was in the mode of deciding whether to waste a month finding another, or starting it on my own with demo and whatnot.In the end I went with a GC.