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Tongue-and-groove plywood wall sheathing?

Lance Peters | Posted in Energy Efficiency and Durability on

So I’m contemplating the use of plywood exterior wall sheathing.  Having handled truckloads of plywood in a previous life, I’m well aware that 1/2″ plywood can be less than flat, and ordinary spruce ply can be full of voids and imperfections.

So if I use plywood to sheathe my walls it will likely be 5/8″ thick.  T&G is usually the same price as standard square edge.  For exterior sheathing is there a preference one way or the other?  T&G looks attractive since it would be easy to stack the sheets.

Typically there’s a 1/8″ gap left between exterior sheathing sheets for expansion.  Would this be an issue if using T&G locked together?  Also, plywood is usually a full 48″ x 96″.  Having 1/8″ gaps adding up on longer walls could shift the sheet edges away from stud centers.

Am I worried about nothing here, or are these common practices?  Is trimming 1/8″ from each sheet necessary?  The back wall of the house is almost 60′ long.

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Replies

  1. Expert Member
    Akos | | #1

    Lance,

    You can use T&G but only if you go perpendicular to your studs otherwise the joints don't fall onto studs. With square edge, you can put the sheets in either orientation. I've used T&G plywood for interior walls, the hard part is hammering them together to get the joint nice and even.

    For exterior walls, square edge is simpler.

  2. Expert Member
    Malcolm Taylor | | #2

    Lance,

    Even at 24" oc. 1/2" plywood loses any of it's waviness once it is secured to the framing. The exterior grade plywood and OSB sold for sheathing already is 1/8" short of 8 ft. It's typically only cabinet grade sheets that are full, or oversized.

    There is some case for using t&g as roof sheathing (although even at 24"oc. 1/2" can be used without H-clips), but there are no lateral p0int loads on walls, so there is really no advantage.

  3. Lance Peters | | #3

    Thanks for the replies! I had read them a while back and gotten distracted before responding.

    Akos, yes, the plan would be to use the sheets perpendicular to the studs. Hammering the sheets together definitely could be a challenge.

    Malcolm, thanks for that info! Good to know the sheets are already sized that way. Funny, I delivered dozens of houses worth of material in a previous life but never thought about the actual size of the panels.

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