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Moisture barrier for Stucco

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  • Moisture barrier for Stucco

    I am working with the customer that wants the old 3 coat portland based stucco applied to his addition.

    The question is , according to my research "D" building paper or stucco rap tyvek is to be used to cover the osb exterior , them the lath with its paper is applied. The problem is that I cannot locate "D" grade building paper in this region. A roofing supply has tried to convince me that their fiber glass base is the same product. Is this a sutiable product for this application ? And what would be wrong with 30lb felt ?

    Any help would be apeciated

  • #2
    Re: Moisture barrier for Stucco

    Code requires 2 layers of grade "D" paper, and you can no longer use roofing felt. I am not sure I agree with that, but it's code. I use Fortifiber's 60 minute JumboTex.



    • #3
      Re: Moisture barrier for Stucco

      Thanks Dick

      I was not too sure of the roofing supplys recomendation to begin with .

      I E-mailed jumbo tex in order to find a local distributer so we'll see.

      We just don't have acess to those products in this region , believe it or not builders still use roofing felt or house wrap to cover the exterior walls.

      Are there some other manafactures of "D" grade paper on the market ?


      • #4
        Re: Moisture barrier for Stucco

        Hi John,

        Check the federal standard for the fiberglass-reinforced product the roofing supply company is using. If it meets Federal Specification UU-B-790a and is rated as a 30 or 60 minute product it will be sufficient for use with conventional 3-coat when 2 layers are applied.

        ONE TEAM - ONE FIGHT!!!



        • #5
          Re: Moisture barrier for Stucco


          UBC/CBC ยง2506.4 is explicit: "Weather-resistive barriers shall be installed as required in Section 1402.1 and, when applied over wood base sheathing, shall include two layers of Grade D paper". If there is no wood sheathing, then roofing paper is OK.


          • #6
            Re: Moisture barrier for Stucco

            Hi Dick,

            I'm not disputing what you said. What I'm saying is that if John checks the product specifications and finds that it meets the federal code cited, than it is classified as a Grade D paper. That might be what the supply house is trying to make him understand.

            ONE TEAM - ONE FIGHT!!!



            • #7
              Re: Moisture barrier for Stucco

              Thanks Dick and Mike.

              The I checked GAF's specs on the fiberglass base materal and is not classified as a grade "D" paper as the salesman claimed. Thats such a regional product that nobody nows of it or they think its red rosin paper in this area.

              I guess the stucco tyvek will be my only option , I'm concerned with giving the homeouner a good finished product without spending an excessive amount of dollars.

              Well thanks again did't mean too stirr things up , I do agree code is code epecially on a product that gets a lot of negitave publicity due too ignorance in building practaces and inproper understanding of the entire system


              • #8
                Re: Moisture barrier for Stucco


                You must be somewhere near me. Grade D paper is not a term understood in NC (except by people who came here from somewhere else and there is a helluva lot of that going on).

                Red Rosin is what most people say if you ask them about Grade D paper. But Red Rosin is also any roll of paper that is pink like what you see in a meat market, which is purchased and placed on the shelf at a lumber supply adjacent to the felt. If it is on a shelf in at Home Depot, it must be code acceptable for something, right?

                I can't imagine using anything under conventional stucco except felt. And, the paper face lath is a real problem too. It's impossible to lap it correctly between adjacent pieces. We don't allow it's use at all in our specs.

                The new stuff hasn't made its way to the east coast.



                • #9
                  Re: Moisture barrier for Stucco

                  Ha Glenn

                  You must have a good sense of humor.

                  On offince intended but that sounds like weekend warrier logic.

                  Felt is not recomended as Dick mentioned peviously. And removing the paper form the lath is asking for definate problems , if you have been reading your JLC magazine they had a very good article on the uses of raps and the like and the long term effects of moisture infiltration.

                  I'm in Missouri and stucco is somthing you run into on the old houses that were built back in the 19 teens up to the 1930's . Brick and vinyl siding are the most comman exterior coverings in these parts.


                  • #10
                    Re: Moisture barrier for Stucco


                    Very good article in this month's JLC about stucco. Saw some things there that could be disputed locally but overall it hits the mark.

                    ONE TEAM - ONE FIGHT!!!



                    • #11
                      Re: Moisture barrier for Stucco

                      Thanks Mike for the help and good timing of JLC.



                      • #12
                        Re: Moisture barrier for Stucco


                        Yes, I was trying to be a bit light. Humor is a good thing. Aside from that, I'm dead serious regarding my technical comments.

                        I'm convinced that few people on this forum are aware of the differences in methods of construction that prevail across the nation. There is more than one good way to do things and climate makes a difference as well.

                        I was oblivios to it for a long time until I got my chops busted on a compuserve forum 15 years ago time after time. In NC, SC, and Georgia things are different than other places - not wrong, just different. But I think of California as being overregulated by underqualified people who just want to be in control. They stymy inovation. Felt may not be approved on the west coast but its REQUIRED here behind conventional stucco.

                        And while I'm at it,here's another example of regional differences. I was surprised to learn how differently vinyl siding is accepted across the nation. Here, no upscale neighborhood will allow the use of vinyl siding. Also most upscale neighborhoods architectural review boards require that the roofs either be slate, fake slate, clay tile, or fake clay tile which may be architectural cute, but galactically stupid in terms of performance and costs. Conventional fiberglass shingles are not allowed.

                        So what may seem like "weekend warrior logic" from your narrow view, may be the norm in other places and not necessarily inferior. I would admit that we often have our hands full trying to be sure that the guys put the lath on with the correct side out.

                        And, what in the world do you know about Stucco Tyvek? Couldn't be much. DuPont just tells you how good it is, and builders just blindly buy it and stick it on a house. That's nuts. Do you think Dupont is going to come to your aid when the wall leaks? NO. And that's a fact -- been there.

                        I don't want to stir that topic up again, but you may as well use nothing as to use Tyvek for a moisture barrier.

                        (Dupont does make one good product -- Flexwrap. That is great stuff.)

                        As for the paper faced lath. I wasn't suggesting to leave the paper off. I was suggesting to put it on prior to installing unfaced lath, but using felt, not paper.

                        Here's where I'm coming from. In the mid 90's I was selected to work with a group of experts in a study with a particular manufacturer regarding some moisture intrusion issues. We had a summit for the purpose of rewriting the manufacturer's reomcendation for synthetic and conventional stucco products. A room full of experts came together to hash out the pros and cons. An old timer who is a nationally known "walls and ceilings" expert, and a long time consultant for the industry was there. He mentioned during one of our brainstorming sessions his concerns regarding paperbacked lath. He was very emphatic and it was based upon some of his examinations. I remember him quoting the ASTM standard and stating that it was almost impossilbe to construct a conventional stucco wall with paper back lath without violating the requirements of the standard. It had to do with the ability to lap the paper and the lath properly and to be able to develop a "key" which is the geometry of the stucco around the lath that provides holding power. I'm sorry I can't be more specific because I can't remember the details, and it has never come up again here, because we use felt and unbacked lath. But this man convinced some brilliant people sitting in that room that paperbacked lath was a major goof and it was ultimately removed from the recommended specifications provided by this particular manufacturer.

                        That's about all I can tell you without spending some more time on it or contacting this gentlemen who had been a wall industry consultant for several decades.

                        Take it for what its worth or ignore it. It doesn't matter to me. Just passing on the information that I have. Perhaps someone else can look into it.

                        Felt not recommended by WHO? It's REQUIRED here.
                        I guess we just havn't gotten the word over here, right? We also use felt under hardwood floors. Although some yankees here use rosin paper. We use rosin paper to protect the carpet during remodels. Does anyone know what the standard is on rosin paper? What is its permeability?

                        And John, we don't use stucco much here either, but that was the topic wasn't it?

                        We have used some conventional stucco here recently to repair homes that had EIFS when other finishes would not be architecturally acceptable. And its still in the code book. And, There are a lot of old stucco buildings repaired every day.

                        But stucco is a good product. Better in some locales than others.

                        The JLC magazine is a great publication for applied construction technology but it is far from a scientific journal.

                        My vision for this forum is not to evaluate constuction methods based upon whether or not the product is approved by the building code or recommended by some manufacturer, but to take it beyond that in hopes that we (somebody) can stimulate some thought "outside the box" and ultimately improve our codes which have always seemed to be a decade a more behind to me. So to say that you shouldn't use a product because its not permitted falls way short of where we could be if we discussed material properties, testing, and performance on a more scientific level. We used to do a lot more of that on this forum.

                        I remember someone citing the standard for Class D paper once on this forum a few years ago. it was the first time I had heard about it and I've been a consultant in light construction for over 30 years. It just simply never used in light construciton here but now you hear more about it now that almost 30% of the population here came from New York or New Jersey. (Our wonderful southern culture is fading away)



                        • #13
                          Re: Moisture barrier for Stucco

                          For more on the differences between asphalt felt and Grade D paper, see "Choosing a Sheathing Wrap" in the Aug. 2000 issue of JLC. Briefly: asphalt felt is asphalt-impregnated recycled paper, while Grade D paper is asphalt-impregnated virgin Kraft paper. 30-minute Grade D paper weighs much less than asphalt felt (only 42% as much as #15 felt, and only 14% as much as #30 felt). 60-minute Grade D paper also weighs less than asphalt felt (only 67% as much as #15 felt, and only 22% as much as #30 felt). Because asphalt felt is heavier, and contains more asphalt, it is more water resistant than Grade D paper. 60-minute Grade D paper (2 Pli Super Jumbo Tex from Fortifiber) endured only 1 hour 3 minutes in the ASTM D779 boat test, compared to 6 hours 13 minutes for #15 asphalt felt, according to recent lab tests reported in the August 2003 issue of Energy Design Update. Anyone substituting asphalt felt for Grade D paper is getting a more water-resistant product and, in my opinion, a better product.


                          • #14
                            Re: Moisture barrier for Stucco

                            Hey Glen--

                            Tell us what you REALLY think about StuccoWrap!

                            Seriously, I've got a $150 roll of it on site, waiting for the crew to install on a small addition--prior to installing lathe and traditional 3-coat mix. The stucco guys, (2nd and 3rd generation union plasterers) also think I'm nutz for spec'ing the stuff--they said, OK, go ahead and use the StuccoWrap, but we're gonna use felt on top of it ANYWAY.

                            I'm a firm believer of the durabilty of stucco--I've seen old, abandoned adobe buildings in the New Mexico desert, 20" thick walls melting away--but that 1" skin of stucco on stucco netting (1 1/2" 20 ga hex) standing up, still supporting the ends of the collapsed vigas (peeled log roof beams).

                            I've also remodeled a 1917 craftsman bungalow with bulletproof stucco on wood lathe--and the felt (+/- 15#) behind it, though somewhat brittle, was still intact. So I'm with you on the durability of felt, too.

                            (it's notable that this house had 4' roof overhangs--and a concrete foundation ((see recent thread on concrete vs cmu))--which both contributed to the superb condition of the cladding)

                            But what's the beef with StuccoWrap?



                            • #15
                              Re: Moisture barrier for Stucco

                              Hello Alan:

                              Well I just learned a lot from Martin. Honestly I don't think I have ever seen grade D paper unless it is that stuff that looks like Kraft paper on one side and shiny black on the other. But I've never seen it in a store around here.

                              Alan, you actually got my attention on a couple of points. I still like subs to use the material that I want them to use. If they are opposed to it, it is my inclination to either inquire and be convinced that what they are doing is better, or find another crew that agrees with my methods. After all, I (wearing a general contractor hat) am going to be liable as well, and the subs may be less informed than I.

                              In fact I had a job about 15 years ago where we repaired and felted a large house ready for conventional stucco. I contacted some subs and selected the one I liked and he proceeded to tear my felt off. He was going to install EIFS. He totally ignored the fact that I wanted to use conventional stucco. He assumed that I was uninformed and that everyone was using EIFS. I told him that I wanted to leave the felt and use conventional stucco. He left the job with my felt half tore off and told every sub in town that my job was a bad place to work and they boycotted the job. The owner and I staged a firing (he fired me) so he could get someone to do his job.
                              That was years before the big realization that EIFS wouldn't work if you glue it to the sheathing.

                              Getting back to your post Alan, I just think that there is a way to do things I'll call "Best Available Technology" and then there is all this marketing hype, market positioning etc. that is going on.

                              The homebuilding business is huge. If you have a manufacturing plant that makes dog food and dogs ain't popular, you're probably going to figure out a way to add cement to it and smear on the outside of a house and market it as the latest "green" construction siding -- 100% organic and biodegradable. Then the mfg convinces a few lumber yards across the nation that they can be exclusive stocking distibutors if they qualify. To qualify you have to have a $50,000 initial stock order and send someone to our training classe. The Class is $2500 but you'll get a free T-shirt and coffee mug.

                              The next thing you know all the builders are at the lumber yard for the spring bar-b-que and hearing all about these great new products. This is all made possible by the genius of 21 year old Johnny who majored in marketing, just graduated last month and started at the top as Director of Marketing. The emphasis is not on product performance but on affecting the consumers perception of the product performance, whatever it is. It is easier to convince someone that a product is good than to make a good product.

                              We spend our time coming up with new products and new hype while the Japanese out perform us by working on better and cheaper ways to make the same stuff. Then we add a tarriff to it so they can't compete with our junk. (Sorry I'm digressing too much here.)

                              In my opinion, Dupont has solved a lot of the worlds problems. It's a great company. But that was yesterday. Today, its more about marketing. Create something new - anything!--, hype it up, sell it, then dodge the bullets. When the venture goes sour, fire someone for it and try another scam. Who knows. Something good may eventually show up.

                              Stucco wrap is made of Olefin (I believe) a Dupont material. It has the word Stucco on it because there was a large part of the market for Tyvek that learned that it doens't work well with stucco, so they produced the new product that was specifically designed for stucco. How do we know? Because it says so in 12" high letters on the front and there is an ad on the radio 25 times a day.

                              I'm sure they changed something other than the name but I have never been able to pinpoint anything of substance. And if what they changed is a secret, that is as good of a reason as any not to use it until its been widely used for about 30 years with no problems.

                              Some would argue that the new product evolution moves faster than that and they want to be on the leading edge of technology. Baloney!. The leading edge of technology should be called the "bleeding edge of technology". I'm not interested in being a statistic so I'll stick with tried and proven.
                              I don't think it will hurt anything to add a layer of Tyvek, but I don't think it will help much. The best way to get me to change is to give me a good scientific basis for switching (not marketing crap) followed up with some legitimate unbiased testing. Then I MIGHT give it a try.
                              But we don't think that way. It's not profitable enough. You have to hire engineers, and do real research and that cost money.

                              Marketing hype can be fabricated by a liberal arts student who majored in raising hell. This person is not interested in making superior products but in working his way to the top of the management pile by starting near the top and showing good profits. You do that by taking chicken sh&* and selling it as chicken salad at caviar prices.

                              I'll stick with #30 felt because that is the closest thing I know of to 15lb felt that was used 50 or more years ago. And, in our area that is still what is being used with stucco. But it sounds like Martin has just given us the best reason to continue using it -- it works better.

                              You asked -- What is the beef with Stucco Wrap? -- My answer to that is why are you using it? On what basis did you select that product? You saw the Dupont ad in the magazine and since its made by Dupont it must be good? Please someone, give me the data on Stucco Wrap like Martin just did with Class D paper and felt. It isn't there. They don't want you to know too much about it because the more you know, the more questions you will have about its effectiveness.