Getting estimated to replace a residential roof that measures just over 3,150 sq. feet and which has 14 facets, 4 valleys. a chimney, the usual roof vents and a slope that is moderate throughout. Estimates I have received have shown differing numbers of bundles and amounts for waste, from as low as 91 to as high as 104. Doing the math myself, I calculated I needed between 94 and 95 bundles (there are 3 bundles per square with this product) using an estimate of 100 sq. ft for each square. What’s a reasonable waste percent, what’s a reasonable number of bundles and what risks do I run if I select a roofer who is trying to get by with no waste?
Thanks for any and all help!
I wouldn’t be worrying about how many bundles they estimated for the job. Find the roofer who you trust to do the best job. If they under order on materials that will be their problem.
Btw I imagine compared to my competition I probably order more materials than they do. I always round up cause they are easy enough to return and the last thing I wanna do is be short on materials.
p.s. no, you are not entitled to money back cause your roofer “over ordered on materials”.
10% is standard for waste and 14 facets is not a straight forward roof.
If they did everything right they should have some material to return, the cost of labor standing idle because of lack of material far exceeds the cost of any of the material on the avg roof.
You will find that the bids will vary regarding the exact area of the roof, if they are within 10% they are essentially the same.
If the exact area of your roof is 31.5 sq I would order 34 2/3 sq of shingles for your roof.
Thanks for your help. What you estimate is close to what I expected and closer to the other 3 estimates – basically, 104 bundles. I also agree with what you said: The cost of labor, not materials, is the lion’s share of the cost, and it costs more in time trying to squeeze use from every square inch of shingles than it does to simply but a sufficient number of bundles.
Beyond the issue of being inefficient standing idle and waiting for more shingles to arrive, does having too few shingles leave some roofers trying to cut corners on how they install what they have, and if that is the case, what sort of things should I be looking out for?
Thanks! I am not expecting money back for ordering too many shingles. I am expecting that the roofer apply the shingles correctly because I know the quality of the work is at least as important, and probably more important, than the quality of the shingles, especially in a circumstance like mine when all the roofers are offering comparable laminate/architectural shingles like Certainteed Landmark and GAF Timberline HD.
I realize that if the under-order on the shingles, that is a problem for the roofer, who then has to order more, but I also worry that a roofer who tries to nearly eliminate waste might do things with the application of shingles that creates problems.
I should add that there will be starter shingle applied along the 255 feet along the eaves and 74 feet of rakes; would that reduce the need for shingles by two or three bundles?
Waste varies depending on the geometry of the roof. For example, valleys create a significant amount of waste. It also depends on the roofer, whether they are bundling in cap and starter into the waste. Is your roof a gable or hip? With 3,150 SF of roof area with 14 facets, I’d expect around 35 squares of field shingles (105 bundles) plus however many bundles are needed for starter and cap. That can vary a bit depending on the exact roof geometry, type of shingle used and the roof crew itself. A top notch crew will salvage more cut scraps to use on other parts of the roof. Most Hispanic crews don’t salvage much of anything, so their waste will be higher.