.#3 Contact Local Contractors for Labor Pricing / Hire a GC to ConsultCall local Subcontractors and get budget pricing for common repairs on your typical rehab project.For example, call a roofer and ask what their average cost per Square of Architectural Asphalt Shingle Roofing would be on a 1,500 sf house, with a 6/12 pitch.Note: Some contractors will be reluctant to share pricing without seeing the property, but tell them you are just looking for a rough budget number you can use on future projects.You can also pay a General Contractor a consulting fee of a couple of hundred dollars (per house) to walkthrough a few properties with you and provide a detailed estimate of prices that you can use as your 'menu for future projects.#4 Compile Your Prices into a Spreadsheet or Estimating SoftwareOnce you start to get a better understanding of Labor and Material costs you will want to store this data into a spreadsheet or software that you can use to help you streamline the estimating process.The Book on Estimating Rehab Costs comes with a spreadsheet that you can use to help you populate your own database of labor pricing and material pricing.

The repair to the roof is pretty straightforward but it depends on roof materials and condition. the other issue could be water damage to the surrounding sheathing and rafters which could cost more. if it was all good, and just a matter of removing chimney and replacing sheathing and tooting in asphalt shingles, I'd probably do it for 1000 if it was a day project.

Cost summary through framing phase $43,149:Framing lumber $18,376Framing contractor $15,010Other costs $9,763: Builder's risk insurance, shingles, fireplace, water tap-in, misc.

Likely water damage / plywood rotting away under the shingles so it sagging.

I ask them, "If I was standing right in front of the property itself, is there anything obvious I would see that would catch my attention from the outside like peeling paint, missing roof shingles, mattresses on the porch  or a rotting fence?

3 bed 2 bath duplex in a solid "B" area about 5 min away from an Air Force Base 1400 sq ft on each side. seller also installed a new architect shingle roof after purchase for us,  mortgage  675 average rent for the neighborhood is 850 to 900It needed some work and truth be told I never really worked with tools before.

Composite shingle, single layer tear off and replacement, Single story, moderate pitch (easy to walk on).

Older houses with some broken asbestos shingles.

We're talking behind door mouldings, under roof shingles, in the walls, etc... 

Roof appears to be in good condition with no shingles missing.