3 unit apartment - Forced Appreciation questions

[Andrew Michaud]

I am looking into purchasing a 3 unit apartment. The apartment is split into two separate buildings. One building is a duplex and the other is a 1 bedroom house (very small). So from what I have read up on, appraisal value on 1-4 unit properties are based on comps in the area. This property will cash flow which is most important to me, but I am also looking further into other possibilities in the long term for this property! CAP rate is 13%, CoC Return is 80%.

What have you guys experienced with appreciation after rehabs on 1-4 unit multi family properties? This property needs a new roof, new windows, new vinyl siding (currently cedar shake siding). I am a building contractor and actually have 80% of materials to do all of this work already from previous jobs.

To put a new roof on the property it will typically cost $11,000 labor and materials. It will cost me 2 days of labor between me and my guys as I already have the material at no cost saved from other jobs in the past 2 years. How much room for appreciation would a new roof force onto this property? I feel I have a lot of room to totally rehab this property for very cheap and most of the cost will be labor paid to my crew but will it make a significant difference in forced value?

What differences in value have you guys noticed before and after a rehab on 1-4 unit multi family properties?