Vapor barrier for shed?
I’m building a shed and not sure how/if to put in a vapor barrier.
The shed is 2×4 framed 16″ OC. I’ll be using LP Smartside panels for siding with no OSB sheathing underneath.
Future plans might call for insulating the shed, likely with fiberglass batts. Any heat would be resistive electric.
My question is should I wrap the studs with some sort of Tyvek vapor barrier before attaching LP Smartside siding panels? If I do apply vapor barrier, then it would seem I won’t be able to use construction adhesive to attach panels to the studs.
I’m not clear on what would be the purpose of this vapor barrier? It would seem to protect any future insulation from moisture that might get behind the Smartside Panels.
Is there some other way to protect future insulation from moisture?
Yeah, I’m confused. Any help appreciated.
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Steve,
First of all, Tyvek is not a vapor barrier. Tyvek (like most brands of housewrap) is vapor-permeable.
A housewrap like Tyvek performs as a water-resistive barrier (WRB). Its purpose (as you correctly guessed) is to reduce the chance of water (rain) entering the wall.
According to the installation instructions for SmartSide siding, "LP SmartSide 76 Series lap siding may be attached directly to framing members spaced up to a maximum of 24 in (600 mm) on center." So you don't need any sheathing under the siding. The installation instructions explain that SmartSide is installed with nails or screws, not adhesive.
Installing some type of WRB like Tyvek under the siding is a code requirement and a good idea.
Hi Martin,
Thanks for helping me think that through. I was considering adhesive just to get a little more structural rigidity, but agree that WRB make sense even if it means I can't use the adhesive.
Steve