Negotiating favorable terms like a low interest rate or interest-only payments for the first few years could help manage cash flow until renovations are complete.

With that said, the income can still offset the cost of holding the property as a long-term investment.

When a PM does charge a markup, he's usually getting a discount on the service to keep the cost stable.

Cost approach A straightforward method that adds the cost of the land to the cost of building construction.

Is there any good rules of thumb to estimating the cost of a boiler?

Low maintenance building, top-end rents for the area due to the extensive work that was done and the location.

Let's say at 6% over 30Yrs will be about $960 per month(Principle/Interest) with the remaining  interest only portion $40K costing roughly $200 per month. $1500- $960 + $200 IS $340Cash in your pocket after everything roughly $1500-$1160-$340 which is not bad for a 100% financed deal(INFINITE RETURNS)Now, If you ran this analysis on a 1% deal as @Nicholas L. mentioned you will undoubtably end up in the red each month.All the best!!!

We are in a constricted market cycle, low volume, strained budgets, high costs.

My cost wont necessarily be the same or comparable as I GC my own projects and have trade skills.

The 6.75 rate is a conventional 30 year w low closing fees (the credit union I used last time).