Metal Roofers.

We have started bidding metal roofs. This is an area that I am not too familiar with. This particular roof is 82sq, has four hips and two sets of valleys. The longest run is 32' to the ridge.

What percentage should I figure in for waste on my bid?

Thanks fellas, all good info. Bill, I use that slope factor on the shingle/tile work we do but it never occured to me to use it on metal, that said I am bidding it from a scaled print so should'nt need it but will remember it for any "footprint" bids that come in. Egg, I thought that was a rhetorical question so didn't ask it. The fact that you did and the answer given proved me wrong. Thanks. Tinner, On your points alone I now need to revisit the whole thing or will be way high, appreciated.

egg Said: Does anybody use valley drop-off on hips and vice versa?

WildBill Said: I usually do a panel layout also, and then add a few of the longest panels, but not anywhere close to what tinner is adding. On a job like you are talking about, I might only order 2 or 3 of the longest panels extra.

I order more because of the way I like to reshape, and redesign around penetrations, etc. If a pipe is in a run, I order 2 panels, 1 from the eave to above the pipe, 1 from below the pipe to above the ridge for working room. I've never used those butyl boots, and I really do the same for SL's, hatches, or hwatever else I run into. I hedged my answer to Jed some too. I'd rather him get too much, than too little. And roofer's styles vary, which can and will affect the number used.

Does anybody use valley drop-off on hips and vice versa?

I usually do a panel layout also, and then add a few of the longest panels, but not anywhere close to what tinner is adding. On a job like you are talking about, I might only order 2 or 3 of the longest panels extra.

We use a software program called "topview" to do panel layouts on cut-up roofs like the one you are talking about.

If you order your panels cut to the exact lengths, theoretically the waste you have on hips and valleys is the length of the hips and valleys x the panel width x the slope factor.

If you have the same slope on both sides of the hip or valley, a simple way to figure the panel add or drop is just: the panel width x the slope factor.

here is a link for the slope factor...

http://www.everlastroofing.com/chart_slope.pdf

for example if you are laying 16" wide panel on a 5 to 12 slope....the slope factor is 1.0833....so you know your add or deduct will be 16" x 1.0833 = 17.3328"

Like tinner said I do an exact lay out of the roof and how many panels and measure to the longest point on each. You could figure out the angle of the hip or valley and transfer that to the width of your panel to see how much longer each panel needs to be for the angle.

I never exactly think about it Jed. If I have exact dimensions, I figure how many panels and add about 2 for each 'area'. Then, I try to order about 8 more sheets of stock than I think I really need. I'd say 10%. fwiw.

Valleys, I figure from longest over to shortest by long lenght, an add a couple there too.