Exterior Sheathing Question

tthomas

I'm looking at a re siding job, taking of the cedar and putting up Hardi-Plank. Under the cedar there is no house wrap and it has, what I was told, is a product called buildrite or one guy called it black board??

Questions goes as follows:
A: do I need to put a plywood/osb sheathing over this so prvent "waves" in the siding?

B: If so do I need to worry about those two products sweating or causing moisture build up between them?

C: if that is the case how would I go about preventing that?

I will house wrap it either way with Tyvec

Thanks
Todd

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Todd Thomas
Thomas Construction
1Tim. 1:16

mattp

I believe they make a special house wrap for hardie. One which allows the water to wick down between the siding and housewrap. I believe it's called Raindrop housewrap.

Amar

I hate the black stuff. Its very difficult to find the studs and very messy. Back when I was learning, we did a house and didn't house wrap over it. I got a call back last month because a tree hit a part of the gable pretty hard. I replaced the hardi plank, and double checked the backing. There was very little water back there (mainly due to the storm and pieces crushed completly thru wall). Other than that no problems. There was no mold around on the back of the hardi plank. That house was done like 6 years ago back when I couldn't bend a brick molding.

Tom Struble

i like to install 1/2 osb then tyvek forget the foam

wallmaxx

Do you mean black board like this?


It is low end stuff that all the cut throat builder's used for a while to save a buck. This stuff was said to be "structural" . The brand was Fiber Brace. Everyone in Memphis used it 3-4 years ago.

It was pretty rigid and they sided right over it...no house wrap. I would not recommend that. Verify how rigid yours is. Maybe your customer can be educated in the advantage of replacing the black board with CDX so the Hardie looks best...for YEARS.

Tom Struble

there is now sheathing on the market and the claim is no water barrier nesessary i think its called zip wall