Who's doing the work, and how is it being payed for? If you had a contractor that could give you a bid for around 80k to do the whole thing, and he was honest, quick, and never made any mistakes, and you had 115k laying around, I'd sat it's a no brainer.
More realistically, I don't know what material costs are on your side of the world, but I flipped a 4/2 here (without doing the roof), and I was into it for around 50k... but I did a lot of the work myself, and part of that is a year of holding costs because contractors bailed, worked slow, or never returned bids... So I ended up hiring a helper and doing most of it myself.
I also had access to the money to finish the project, but it tied my real estate investing hands up for over a year.
So... if material costs are close to mine, you have the same contractor issues I did, and you can do a lot of the work yourself... and the roof costs less than 30k, I'd say there's potential. Now, if by gutting it, you mean you have to do all new insulation, wiring, and plumbing?... at least in my area, that would not make money at all.... as an investment... might be worth $25/hour if you do it all yourself.