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This is insane. The point of typar is to prevent water that gets through the siding from getting the sheathing wet. It serves no purpose at all inside the sheathing, unless they are also putting it outside the sheathing as well, and putting it inside is for some insulation purpose that I don’t know about.
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This is insane. The point of typar is to prevent water that gets through the siding from getting the sheathing wet. It serves no purpose at all inside the sheathing, unless they are also putting it outside the sheathing as well, and putting it inside is for some insulation purpose that I don't know about.
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Can't understand the rationale and sure makes inspecting the quality of the tyvek installation impossible.
In a proper installation, as per manufacturers recommendations, there is only one way to install this product and that is on the outside of the sheating, properly taped and all seams from top to bottom, secure and tight.
Experiment and you're on your own.
*Jim, the point of housewrap is not to keep the sheathing dry.Continual exposure to moisture will absord through to wet the sheathing.The purpose of housewrap(actually called an air infiltration barrier)is to stop air from infiltrating(hence the proper name)the walls of the house.Supposedly, it still lets the house breathe. Cole,I agree,housewrap should be installed on the outside of the sheathing as Gabe describes.In theory though,the housewrap will still serve its purpose installed under the sheathing.I would think if it is going to stop air infiltration on top of the sheathing,it would still stop it under the sheathing.I do know that the use of housewrap is being questioned now,because of moisture getting through it,then being trapped between it and the sheathing.Thus rotting the sheathing and framing members prematurely. Maybe that's why these guys are installing it under the sheathing,so as not to trap moisture.I don't know, just taking a shot in the dark.
*So are they using some other underlayment over the sheathing? I thought Tyvex was supposed to let water vapor but not air through, -and- to repel liquid water from rain. Though from all I've heard here, it sounds like felt is still better than high-tech?
*Maj, your closer to the truth.Tyvek is indeed a wind infiltration barrier. It theoretically will prevent moving air from entering the shell, thus allowing the insulation to properly do it's job. Fiberglass batts are not too effective with wind being forced through them.One of the defects of Tyvek is it's tendency to break down due to exposure to the sun's ultraviolet rays. Read the small print and you will notice that there are a lot of "strings" attached to maintain the warranty. Overexposure to the sun, and too many nail holes voids the warranty. Maybe the carpenters are installing it to prevent the over exposure. Maybe they just dont want to have to nail it. The sheating will do a pretty good job of keeping it on the house. The housewrap should extend below the plates to be of any help at all. This is the one area that house wrap would actually be of benenfit. Caulking under the plates would work too. The conection to the foundation is also a key air infiltration point. Tyvek is supposed to allow moisture to move through it. I'm sure that the tyvek people will say that the house was not properly built due to insufficient moisture barrier.I think tyvek is a poor substitution for good framing techniques, and proper sealing of trouble spots. Air isn't going to blow trhough properly installed osb sheathing. I prefer to seal the bond to the foundation with roofing cement and tarpaper and eliminate the wraps. It works fine!Blue, winded in MI"Forget the Joneses, I keep up with the Simpsons."
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You are all very much correct. Blue, you hit the nail on head, proper framing and sheathing techniques will not require the installation of tyvek or felt paper. And with the exception of masonary or stone veneers, "sheathing paper" is not required by code to be installed under most sidings. I have always used felt paper and will continue to do so. I used tyvek once and never saw any need to use it again. Air infiltration measures are best taken at door, window, wall and ceiling penetrations.
As far as these guys that applied housewrap to the studs under the sheathing, congratulations, you may have just recreated the old double vapor barrier idea of the sixties which has been proven to rot the walls out. Although this may have been innocent, misuse or misapplication of products is a leading cause of failures and defects.
In 25 years of construction I have seen contractors cut corners to save nickels yet waste dollars on this stuff.
Heres a tip for sealing those 1/8" spaces you are supposed to have in sheathing joints, for the horizontal joints apply caulking tape to the secured edge of the sheet and drop the next one on. The vertical joints are easier to tube caulk. When the sheets expand and they will, the seal gets tighter.
I am all for innovation and technology but my opinion is this product has been over sold in both catagories. Someday I may find a need to use housewrap for a particular installation, I wonder if it will still be on the market.
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You're right Keith, paper is no longer required under siding. It is just a throw back to the old days when sheathing was individual boards. The diagonal boards were very porous, and the tar paper windproofed the house (remember, they also didn't install insulation).
Ply wood sheathing will stop ALL air infiltration if basic principles are applied: Nail all edges 8"oc min, block all joints and nail 8" oc.
Even the expansion gap becomes a moot point if the nailing is done properly.
Tyvek is the biggest scam foisted on the public since I've been in carpentry! And they are eating it up!
Blue
*Installing Tyvek, so that the warning about ladders slipping is not clearly visible from the exterior of the building where a ladder is likely to be leaned is a violation of OSHA regulations. That is of course unless it is covered with sheathing that is OSHA approved as slip resistant.
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I guess this would count as another good reason not to use tyvek. Regulations don't have to make sense over reality. Poor means and methods don't surpass proper construction techniques. Sorry!
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Keith, I forgot to mention that we use tyvek as brick underlayment, on walls that are too small to install a windbrace. We have alot of these types of walls. We've also used felt, but tyvek is faster. It doesn't tear, so we staple it with wide crown staples.
The best feature is the size. I whack the nine foot rolls into smaller sizes, usually 5' and 4'. Sometimes 2, 3, and 4 footer's.
These smaller rolls are quite handy, light, and much easier to handle than the heavier tar paper rolls.
Of course, I'm not the one paying, and I've never compared the cost. I'm sure the tar paper is a better buy.
I wouldn't put the stuff on a dog house otherwise, but I've heard it makes a great material for sailing.
Blue
What did the teacher mean when she said to me; "Your kid may be an honor student, but you're still an idiot." ?
*Since everyone is so good about expressing there opinions on this website,how about my way of sealing and protecting the house???I like to use 7/16"OSB wall sheathing laid horizontal(proper nailing of course),1/2" rigid foam over that with all joints staggered from the OSB(laid vertical),then I use tyvek tape to seal the joints of the foam.In our area we use alot of vinyl siding(oops, I used the v-word)I know it's a sore subject,but it is what everyone here seems to want.I use no housewraps or felt under vinyl,however felt under cedar is the only way as far as I'm concerned.How about it,good or bad???
*maj,Your way is my way in many cases. The "multiple layers are better" crowd are the ones who scare me in this forum and the real world. Such as foam, then taped seams, then tyvek,etc...what the heck are these people thinking? As all can probably tell I've joined the Fred L camp and will be spreading "the word" according to Building Science Corporation also on my visits here and elsewhere. Modern homes have major hidden problems in the walls and attics that time will soon enough expose. Density and critical mass...when enough people ask why they are having to repair the structure of a ten year old home when Grandma's home is over one hundred years old and still going, then and only then will the tide change.Has anyone followed the mid-East coast on going saga of thousands of failed stucco over insulation board failures? All you caulkers out there, is the caulk working for these people. NOT! Read my sponge, capillary analogy elswhere in the "Joe tries to torch Fred L and all out of Breaktime, for differences in opinion threads; its a fun dog fight.Not for trapped moisture,Jack : )
*Jack, I just left the Building Science Corp. webpage. Very interesting!!!!I really like most of their techniques,but I think it is going to be difficult to convince people in my area to change the way we build around here.Very conservative people,and not much for changes(if you know what I mean).I am not a fan of housewraps,that is why I try to convince them in useing the rigid foam with taped seams.I still get harrassed by "older" builders for useing the two stud corner.They seam to think the house will tip over or something.As I stated earlier, I use OSB for the base sheathing because,unfortunately,vinyl siding is very popular around here.It makes it easier for fastening corners,J-channel,shutters,etc.Also,alot of my work is as a subcontractor,with the G.C. being the owner of the local lumberyard,so it is difficult for me to change his building practices.I may need to sit down with him and discuss other alternatives.Thanks for advise.
*Maj,Thanks. As for housewraps...they are a good product but so is 15# felt. Vinyl over taped foam or housewrap is a natural. And taping the wrap to the window flanges is another detail I take the time to do. I don't think there is a problem with wrap or felt over wood sheathing either. I do think housewrap with foam is a real iffy situation and may be a moisture trap. I have no problem with OSB under foam but am leaning toward the "wood at corners only,foam sheet the rest" school of the thought in my future.Glad you have a foot in the Fred L Camp,Less is more,Jack : )
*Hi JackChecked out the Building Science site, thanks for the link. Did you realize that not only are they showing f/g symbols for insul, and refering to f/g R values in their text, but they actually show roof venting, and how to cut up a sheet of ply to make soffitt's that include soffitt vents??? Doesn't sound like a Freddy Lu kind of site to me!!! Just when I was ready to move on Joe Lstiburek wants to drag me back. Darn Canadians. . . must be a cultural thing. LOL
*Patrick,You've gotta read his books or better yet catch one of his seminars...Joe L. is amazing and has more energy than my two nephews and cat combined!I audio taped the time I saw him and if I can dig it up I might send you a copy if you'd like.I'm sold on Joe L. in a big way and agree often with Fred L and Gene Leger...Personally I believe many insulation building methods work reasonably well, for each ofus, including the "two wrongs to make it right" FG/poly/venting methods. I also knowsome of the methods used today are failing hugely, I and Fred and mostremodelers who rip open walls have seen the failures. And the worst of what I see is in construction since we all started building "tighter homes" for less Arab oil dependency.It's not Fiberglass and poly and vents...verses... dense pack cellulose and a well sealed living space...To me it's what I see not working, and thehuge cost to repair...verses...simple building systems that perform their job better, longer, for less cost, highercomfort, cleaner air, less maintenance, less technical.....etc.Proud to have your fellow Canadian living down here in the "neighborhood'Jack : )
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I usually see tyvek installed on the exterior side of sheathing in our area.
Recently though several builders have started placing it inside between the sheathing and framing (I think to keep it from ripping and blowing in wind). Does this affect performance? good idea??
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You have to see the Don Lewis response in the
Typar discussion about 20 or so topics above your
site. He confirms what we saw when Tyvek first appeared. Since APA rated panels are rated
moisture barriers, there is no way any moisture
egressing from the wall cavity will ever pass
beyond the sheating. To paraphrase Mr. Lewis,
it sure serves no purpose, but is expensive.
I think the building wrap people owe you an
awful lot of compensation for this scam.