When my house was built, the builder put the Tyvek wrap on the frame of the house, then installed the sheathing and then installed the siding. I am about to have my siding replaced and one of the contractors wants to take down all the siding and sheathing and peel off the Tyvek, then put sheathing back on, then Tyvek wrap it and then install the siding. He claims if I don't do this it will void the warranty on the James Hardy siding. I am aware that I may have some sheathing damage, but I don't see any reason to do all this as I can't believe it would void the Hardy siding warranty. Another contractor wants to put another layer of Tyvek on the outside of the sheathing and leave the old Tyvek underneath the sheathing. I am also not sure this would be a good idea since you could trap moisture on the sheathing that would now be in the middle and then I would have mold and mildew in there if moisture did penetrate. I would take any information that someone might have about how to handle the situation.

  • 3
    I agree that it sounds a bit sketchy. I would suggest that you contact James Hardy yourself to ask them if it voids their warranty to not strip the wall back to studs. If they say it doesn't (and point you to a copy of the warranty info on their website that you can download & print), then tell your contractor to stuff it. If he's found actual damage, then yes, replace that, otherwise, you've got it in writing that you'll be fine.
    – FreeMan
    Mar 11 at 11:55
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    I would not want a second layer of house wrap. I would think that would make more problems sandwiching the sheathing.
    – Ed Beal
    Mar 11 at 14:16
  • Tyvek is not acceptable for use with James Hardie siding.
    – Lee Sam
    Mar 11 at 16:55
  • What goes wrong when Tyvek is used under James Hardie planks or sheet? Aug 9 at 1:59
  • @JimStewart not sure if its related, but theres a few huge court cases going through against James Hardy and faulty sidings here in NZ right now, and Hardys defence is “poor installation”. One was just settled for Hardy after the litigants financial backers pulled out, but there are another few cases about to go ahead.
    – Moo
    Aug 9 at 2:26

I can’t imagine that James Hardie will condone the installation of two exterior house wraps (James Hardie calls it : “Weather Barrier”) sandwiching the existing wall sheathing.

The existing sheathing will have moisture in it and probably large amounts of dryrot.

However, you want to install their product, their way, in order to protect the warranty. That’s why it’s important that you have an on-site inspection performed by James Hardie. Make sure you get his report in writing.


Btw, I would not use “Tyvek” or some random caulk. I would use only James Hardie products installed exactly how they recommended. (This includes NOT caulking above windows. This drives every installer crazy, but is required by James Hardie.)

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