Roll roofing question


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Old 03-02-10, 05:38 PM
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Roll roofing question

Hey guys,

When installing roll roofing, where are the proper places to nail? Keep reading to nail 1-2 inches from the edges. But which edges are you nailing? Do you nail at only the top, like you would with shingles, or do you nail at the bottom of each roll where it overlaps?

Nailing at the bottom of each roll would secure the roofing well but will water leak through the nail holes? Should cement be used to cover up and exposed nail heads?

Please help!

Thanks,

---Joe
 
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Old 03-02-10, 05:53 PM
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You can probably get some good installation tips by reading Owens Corning's roll roofing instructions or Tamco's roll roofing instructions.
 

Last edited by XSleeper; 03-02-10 at 06:09 PM.
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Old 03-02-10, 06:18 PM
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Why do they say to use a maximun length of 18 feet? My structure is about 21 feet long and it would seem to be pointless to make a joint for 3 extra feet. I know if i have a 30' roll that i would waste about 9 feet a roll, but woulnt an aplication with no vertical joint have less of a chance to leak?
 
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Old 03-02-10, 06:37 PM
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Tamco evidentally knows that their product expands and contracts at such a rate that if pieces are longer than 18', they will either buckle or tear as they expand and contract. If you wanted to know for sure, you would need to find instructions for your particular brand of roll roofing to know what your manufacturer's installation instructions are. Owens Corning's instructions make no such statement. I just provided them as a general reference.

I would tend to agree that with a 21' roof you would probably want to avoid seams if possible.
 
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Old 03-03-10, 07:01 AM
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Right or wrong I've been nailing down all four edges of my bottom (1st) strip of rolled roofing. Then I put down a continuous bead of roofing tar (I like Leak Stopper brand in the red can) along the top edge. The following rows up the roof only get nailed on three edges, top and both sides. The bottom edge is glued down by the tar. Then when finished laying down the rolled roofing come back and cover every exposed nail head with tar. Save that for end so you don't step in it or accidently put your hand in a blob of tar.

I've done way too many roofs this way and all are shallow pitched add-ons that are quite old. The roofs hold up reasonably well but when they fail it always starts at the very bottom edge or a side. The glued joint between strips has always held. They fail when the sheeting/boards underneath get water damaged and the nails no longer maintain their grip or during extremely high winds when the roofing simply tears leaving a circle of roofing still under the nails. A good wind comes and lifts the edge of the sheet and with every gust of wind it pops or tears through another nail until... So, make sure the underlayment is good and proper. Going cheap and puting roofing over loose or rotten boards only means you will be back up there doing it again. And make sure you do not skimp on the number of nails along the outter edges (sides & bottom). The edge nails are critical and in an area where they get the most abuse and see the highest loads.
 
 

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