After reading the roofing felt thread, I thought I would throw this out there: I am building a pole barn for a client constructed as follows:
1. Half of barn has 8:12 trusses spaced 2′ o.c for the workshop area (heated ocassionally)
2. Other half of barn has 8:12 trusses spaced 7′ o.c. with 2 x 4 purlins on edge at 2′ o.c. vertically.
BTW- I was really impressed with the way they manufactured two different styles of trusses to plane into each other perfectly- with one having a 3 1/2″ purlin atop it and the others to sit ready for sheathing. Boss this may interest you.
3. Entire roof is sheathed with OSB
4. Roofing is 29 ga. Pro-Panel
5. Customer asked me to felt the roof before I sheeted it in steel. I couldn’t really give him a reason not to, but have never seen a barn felted before it was sheeted. Is there a good reason for it. He thought it would be extra insurance against leaks, but I didn’t agree. I felted it anyhow, no big deal.
Any thoughts?
Cole
Cole Dean
Dean Contracting
Replies
I have had several experiences with leaks in pole barn roofs, and felt sounds like a good idea.They usually leak around the nails, which seem to lift up with time. I would use screws to combat this next time.
Metal, in an acid environment, will rusat quicker. Manure creates that environmnet. The felt can separate the metal from the rising vapours.
it also acts to separate the metal from the OSB. The metal will have thermal expansion moving it, as well as rippling from wind. This creates a friction on the bottom of the Propanel against the decking. That could conceiveably accelerate rust.
Excellence is its own reward!
Piffin,
Thanks for the insight, I will take it into account in future installations. Generally, around here, post frame structures don't even get decked, just steel on purlins, but the last two I have done we have decked, it does quiet it down when it rains, and it sure makes working on the roof alot nicer, considering this last one was an 8:12. That steel sure gets slippery.
This structure in particular was built as a garage/workshop area, with concrete floors throughout, thus no ammonia. As I said I had no problem adding the felt, I just couldn't find a reason to do it. Now I have one.
Thanks.
ColeCole Dean
Dean Contracting