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Exterior Shiplap Over Plywood

973 Views 5 Replies 3 Participants Last post by  CentralNY
Hi all,

A landlord here, trying to finish building a garage for some tenants and we're doing all the work ourselves. We're changing direction on the exterior finish during this winter. We were going to install a vinyl siding material … now we want (definitely want) wood shiplap that we will paint.

As it is now, the garage is new (built 6 months ago), detached, slab-on-grade, single-story, unheated, 2x wood framing with 7/16 sheathing all around. There's also a layer of Home Depot brand plastic wrap all around to help protect it from the upstate New York winter.

There is a small chance in the future that I'd spray-foam or cut-to-fit 2" rigid foam insulation in between the studs and install some drywall in certain sections to create a workshop as I obtain other properties in the nearby area.

My main questions:

- Is it acceptable to simply install the shiplap over the wrap?? It would be 7"-8" wide planks X 5/8" or 3/4" thick.
- What if I removed the wrap and did "faux" shiplap directly over the plywood?? Meaning, cut 8" strips of thin plywood and brad nail to the 7/16 sheathing and paint everything??


The garage is 24'x24'x12' tall garage, so the wrap only cost a little over $100 … I'm not going to worry about it if it would be better to be removed.

PS -- I'm a registered architect in some southwest states but recently moved to central NY for family reasons. Definitely trying to read up on where to put the vapor barriers in the buildings up here.


Thanks in advance!!
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The wrap is your weather resistive barrier and it is needed with all joints taped. Leave it in place and put your final finish over it. Not sure what you mean by cutting strips of plywood, but in any event, don't . Use ship lap or go another direction.
If I place spray-foam or rigid foam insulation in between the studs AND have the building wrap/barrier on the outside of the plywood sheathing, should I be worried about moisture getting trapped in between??

Plywood will be between the wrap & foam insulation. I do know that the wrap is not a water barrier nor a vapor barrier. But if I paint or stain the shiplap siding, will any moisture that ends up in the plywood layer be able to sufficiently escape and not rot out the plywood (which is the shearwall)???
If I place spray-foam or rigid foam insulation in between the studs AND have the building wrap/barrier on the outside of the plywood sheathing, should I be worried about moisture getting trapped in between??

Plywood will be between the wrap & foam insulation. I do know that the wrap is not a water barrier nor a vapor barrier. But if I paint or stain the shiplap siding, will any moisture that ends up in the plywood layer be able to sufficiently escape and not rot out the plywood (which is the shearwall)???
House wrap is a water barrier but will let vapour thru. It is fine with what you are doing. But it might be code to have you solid wood spaced from the building. You can have house wrap or tar paper.

Thanks for the help & videos!!
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