You encourage newbies to ask questions so here goes:
I have a 15 year old post built barn with trusses every 12′ and horizontal 2×6 “rafters” every 2 ‘. It was roofed with so-called “lifetime”, composition fiber-type sheet roofing (similar to metal sheets, but not metal). The company is no longer in business in the US and the sheets have deteriorated, so I need to reroof.
I plan to use traditional composition this time and thus need to install plywood over the rafters. I’ve been told we must cut 2x4s to insert between the horizontal rafters, where vertical rafters would be, in order to nail the plywood. Logic tells me, we can just nail the plywood horizontally instead of the more common vertical and dispense with the cost and carpentry (and weight) of additional 2 x 4 s. Will that work?
I have rejected simply replacing the composition sheets with metal ones because of the “dripping”. This is in the NW and the barn is approximately 24 x 62.
Many thanks for your thoughts and expertise on this.
Replies
You should have no problem running the plywood with the grain running vertically, but you should use "h" clips halfway between the rafters on each plywood joint. Incidentally, what you are refering to as rafters are actually called purlins. If you are in doubt as to the placement of the clips have someone at your local lumberyard show you how they are installed. Good luck.
Mark
You should only need to install additional two by blocking between the purloins if you had a reason to run the plywood horizontally. The grain of the plywood needs to run perpendicular to the support members which in your case is in the vertical alignment.
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