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Removing Roof Space Sheating for Radiant Barrier OSB

raygant (Structural) (OP)
12 Dec 11 19:55
1917 Craftsman Bungalow

2 layers of composition shingles over 1 layer wood shake shingles attached to 1 x 4 space sheathing with 4 inch spaces.

I am reroofing and will need to resheath the house.

I want to install 7/16 OSB with a radiant barrier attached to one side.

Can I remove the space sheathing boards and install the OSB directly to the rafters?
raygant (Structural) (OP)
12 Dec 11 19:57
rafters are 24 inches on center
JAE (Structural)
12 Dec 11 20:32
Why wouldn't you?  Not sure I understand why you would question this as most houses have sheathing attached directly to 2x4 rafters.
hokie66 (Structural)
12 Dec 11 20:41
But on the other hand, why would you?  The boards shouldn't do any harm.  You would just have to use longer fasteners.
Ron (Structural)
12 Dec 11 21:30
...and radiant barriers in attics don't work anyway!  Don't waste your money on the radiant barrier.  Re-sheath with or without removal of the present boards..not a big deal either way as long as the additional weight doesn't present a problem.
raygant (Structural) (OP)
12 Dec 11 22:09

My thoughts were that doing the project as described wouldn't be a big deal.  I am curious if the 7/16 OSB is strong enough to span the 24 inch on center rafters.  This was really my big concern and I though I would check with some of you to see if I was missing something.  

As far as the comment about radiant barriers not working in the attic to reflect summer heat... is my information in the link incorrect.  The space is finished directly below the roof (finished attic) but it gets unbearably hot in the summer unless the 220 window AC and the 110 window AC are on full blast; then only tolerable.   
hokie66 (Structural)
12 Dec 11 22:52
I'd like a clarification on Ron's statement as well.  A lot of us think that radiant barriers work, and some claim to know that they do.
Ron (Structural)
13 Dec 11 8:29
Most attic heat is a result of thermal transfer between the exterior face of the roof and the interior of the attic.  Insulation will help that.  Radiant barriers generally have high thermal conduction (e.g., aluminum facings).  They work fine for light emitted heat (by reflection) but less so for non-light thermal transfer. (although there is a significant anomaly in that as well...go out and put your hand on a chrome trim piece on your car on a 90F's hot)

Perhaps my experience is anecdotal....comments please.
hokie66 (Structural)
13 Dec 11 19:03
My experience is totally anecdotal, but in our hot climate, houses and commercial buildings typically have aluminum foil sarking or aluminum foil faced batts installed directly under the roofing.  Maybe this is the wrong forum for good advice on this.

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