I priced out a roof replacement on an 8-unit building (4 upstairs, 4 downstairs) and I can get a new roof on an 8-unit apartment for the same cost as 3 SFHs.Scale is also a magic word along with Exit strategy. 

That would get you close to a solid guess on the replacement cost. 

Hi Calvin, I looked at that one too as it could be a good deal.It's definitely going to be more than 10k based on the details in the MLS:"Just vacated by tenant; Needs cleaning and the flooring is likely to need replacing throughout; Please be aware there is a STRONG PET ODOR in the house and pet damage in places; One window has broken glass and one shower is not usable; I believe one of the toilets is not functioning as well.

I have bids from 3 contractors so far and am getting big variations between contractor quotes.Wondering what the approximate costs are in Central PA region.1) Roof replacement(including front and back porch roofs) is 22 square ( got quotes ranging from 7,000 to 13,000 $) - how much should I expect to pay2) Flooring -  approx 1700 sq.ft of LVP plank flooring after removing carpet ( from 3600$(material separate)  to 7800$( material included)- how much should I expect to pay 3) The home is grounded to plumbing i think ( its constructed in 1960s). 

Eventually I will replace the windows and do other things but its a working progress.

If your still thinking about the appreciation component of it you should stay in Peel Halton York.. $800k you can find something..You can get in Burlington a rare duplex with basement so 3 units..

He asked if he could find a replacement/sub-let which I agreed was fine, pending my approval.

Working on our due diligence phase now, I already know we need to replace the roof, so going to get some bids on that.

The HVAC was replaced 5 years ago.

A couple of my concerns are spending $$ to replace them and still having a price ceiling because the age of the house.