# Attic flooring - OSB or Plywood



## II Weeks (Jan 6, 2009)

1/2" plywood?

Two feet on center?

The boilers in the attic?

Flooring?


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## jlhaslip (Dec 31, 2009)

You would need at least 3/4 inch material to avoid it being springy.


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## ENGINEER10 (Oct 10, 2010)

The additional weight of wood is not a concern, the real problem is the storage in the attic for which the existing and new added joists may not be sufficient. There isn't enough information to go by as to how the joists are supported and their span.

2' spacings, 1/2" plywood or OSB, all these are OK for light storage.


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## tariqk (Oct 18, 2010)

II Weeks said:


> 1/2" plywood?
> - Yes, I was planning to use 1/2" (or maybe 3/4" based on feedback) plywood or OSB.
> 
> Two feet on center?
> ...


Hope this clarifies.

Thanks


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## tariqk (Oct 18, 2010)

Thanks for your response(s). I'll plan to use 3/4" OSB or plywood and leave the spacing between 2x6" as 2'.

Thanks again.


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## Gary in WA (Mar 11, 2009)

For light storage in the attic, I would use 1/2" plywood, cut into 12" rips spaced 1/2" apart. This will let any heat/moisture from the conditioned space below to vent without condensing on the bottom side of the plywood. The framing would sit on 1x4 secured perpendicular to the joists over the bearing points to keep the new joists free-spanning over the bearing wall below. Use a 1x4 on the ends of the new as a rim joist to prevent lateral displacement (tipping over) held flush with the top edge. No OSB as it cannot handle moisture well and mold loves it. Figure the 2x6's at 24"o.c., to *check your spans *by entering them under "ceiling joists w. 20# load" here: http://www.awc.org/calculators/span...d=10&submit=Calculate+Maximum+Horizontal+Span

Gary


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