The job includes removing all osb, installing 5/8 plywood, some type of barrier, 30 pound felt, architectural asphalt shingles that are energy efficient, and a 50 year one time transferrable guarantee. We are being quoted $20,000. They are the same company that just finished our vinyl siding for the same amount. We are extremely pleased with the siding.
That is a fair price for that scope of work.
The estimate depends on the material being used, the type of roof (does it have a lot of cuts), and the local building code requirements. Using 5/8" plywood is more than what is required in my state, but near the coastline or near an area considered probable for hurricanes may require more structural support.
3,500 sq. ft. is 35 squares. Typically, architectural shingles are 33.33 sq. ft./bundle, so 3 bundles = 100 sq. ft. or 1 sq. These shingles typically run $75-$85 per square at any local supplier. However, the energy efficient shingles typically cost double to normal shingles and sometimes they require 4 bundles per square. And, most energy efficient shingles are energy efficient because of their white or very light granules. So, if you are at $175/square just for the shingles that is already $6,125.
Then, you have to add on 5/8" plywood, which runs around $15-$20/sheet. That’s another $2,000. Plus, the ice and water shield, which in areas near the coastline the code may require 36" or more coverage from the interior wall. Then, 30 lbs. felt is the same price as 15 lbs. felt but covers 1/2 of the area so you will need 2x as much felt. Plus, around your valleys, chimneys and possibly skylights, you will need flashing. You will need ventilation, which is about 1 sq. ft. of ventilation for every 150 sq. ft. of area. Then, you will need to add drip edge.
The material alone will probably run you $10,000+. Then, this roof sounds like it has a lot of labor built-in so it may take a while for the guys to finish the roof.
If you are concerned about the price of the quote, I suggest obtaining another quote for comparison. If he is a good contractor, then he is worth it. But, as a homeowner, it may be worth the time to ask for one more quote.
And, the above information is based on knowledge I have in my area. This information could be completely different in your area, so please verify all information in your area to be the most prepared to discuss the quote.
There is an annual publication called “The Cost -vs- Value Report” that provides insight into the prices of over two dozen home improvement projects mapped to specific areas of the country.
In 2105 the report for the Jacksonville, FL area indicates that a 3,000 sq ft roof with a certain set of specs would cost approx ~$6 per sq/ft. Adding in approx 2k for new OSB gives us a average expected price around $23k.
In light of that $20k from your siding contractor would seem to be a good deal. The last factors to consider are the brand / quality / warranty of the materials they are spec’ing and to be certain that the roof “system” being installed is complete and meets all manufacturer requirements for a full warranty. We often see companies skimp on ventilation and underlayments to cut costs.