Mark's estimates weren't too far off, given the limited information available. Michelle described the shed as 16'x19'. We don't know the roof pitch, or the overhangs, but let's assume a gable roof with a typical 6/12 pitch.
6/12 pitch over an 8' span (half the building width) would work out to a 4' rise at the peak. Using Pythagoreans theorem, take 8' squared + 4' squared, then find the square root for 8.9'. Let's round that to 10' since we don't know the overhang. I'll also round up the length to 20' since we don't know the overhang on the ends.That's 10'x20' feet or 200 sq/feet for each side of the roof, or 400 square feet for the entire roof. Using my local Home Depot prices that works out to:
13 sheets plywood ($17.50 for 15/32 CDX, or $10.37 for 7/16 OSB) - $227.50 12 bundles 3-tab shingles ($27 bundle, 3 bundles per square) - $324 1 Roll 15# roofing felt - $21Round that up to account for nails and other extras the total is approximately $600. Of course, this assumes Michelle has the tools and skills to do the work herself. If she has to pay someone to do the work, she's probably looking at least twice that amount, not counting any additional labor costs to demo the original roof.
Of course, this is all meaningless if the underlying structure is rotten. No way to know for sure till the roofing and sheathing are removed, but rot sounds very likely based on Michelle's original description.
Anthony