I looked at a new house where the builder had put the Tyvek behind the OSB. He says he’s been doing this this way for 50 years (50 years and no changes in construction? That’s worrisome by itself) and never had a problem. DuPont doesn’t show this installation on the instructions and I can’t find anything in the literature about it. I’m afraid the OSB will get damp from precipitation on the outside and damp from transpiring vapor on the inside. Any thoughts?
Thanks!
Pretty hard to use as a WRB Water-Resistive Barrier if it is under the osb. What, you don’t want vertical mulch?
Check:
here Install **over all flashing (e.g. wall to **roof intersections and thru-wall flashings).
and
Greg,
It’s simply wrong. Period.
I wish I were there to see this.
That actualy harks back to old style framing before we used structural siding, in the old days they built the frame (including diagonal bracing to prevent racking) then covered it with Tar/Felt paper and nailed either wood lap siding or nailers for shingle through the paper into the framing.
Sounds like your boy is real “old school”, and as others have said, wrong!
BTW I have seen a few garden sheds built that way in the recent past
Regards
Gerry
Sounds like an old dog that did not make or want to learn new tricks.
OSB is not the finish product, and tar paper has been used for ages and always on top of the sheathing.
I used to build houses with my old man and used rough sawn board or 1x6 T&G boards for sheathing, then the tar paper. Hate to say it, but the old man is totally wrong for even then.
Maybe he thought the OSB was the siding. ha. ha.
Marcel 
Biodome without the dome, biobox maybe? :roll:
C:\Documents and Settings\GREG BRAINERD\Desktop\current pictures\Picture 013.jpg
For those of you who wanted a picture, here it is. This is real!
Sorry- the picture insertion didn’t work. I’ll email it to anyone who wants to see it. greg@brainerdhomeinspection.com
How long has Tyvek and OSB been around?
Evolving from waferboard in the late 1970s, OSB is unique in that long wood strands are oriented, not randomly placed. Since its debut in 1978, OSB has been rapidly accepted. In fact, in many areas of North America, OSB has virtually replaced other panels in new residential construction. Today, all model building codes in the U.S. and Canada recognize OSB panels for the same uses as plywood on a thickness-by-thickness basis.
Too long!:mrgreen:
