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If you check Fisette’s article, University of Mass, he concludes that tar paper/felt is best performer for house wrap.
www.umass.edu/bmatwt/weather_barriers.html
Anyone got any ideas on tapes or adhesives that would seal the overlapping joints in asphalt impregnated felt? Also, what do you use to seam seal OSB ?
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Tedd:
So, you say that "Felt is best housewrap because..." Paul Fisette said so!!
I did not find the article you cited as conclusive as you did. Personally, I don't think housewrap or felt is a clear winner. Rather, it's more of a personal preference and realizing that one or the other may be better for a particular situation.
While Mr. Fisette, makes numerous good points; the article represents only 1 person's finding/opinions. His point that felt has the ability to absorb moisture from the underlying sheathing is very significant. Still, he incorrectly refers to the asphalt impregnated felt as "15-pound". Anyone who is aware of current product offerings for asphalt impregnated "felt" knows that it is not necessarily and probably not 15 pounds per square, which is what the 15-pound designation refers to. Rather manufacturers refer to it as "number 15". As a matter of fact - it's not even felt anymore. Of course I wonder if Mr. Fisette knows this since he seems to use felt and paper interchangeably, which are 2 different products, although he hints at this under the subtitle "Building Code Requirements" where he referenced building code and says" Basically, all Model codes agree on the need for a weather-resistant barrier paper (usually specified as #15 felt or Grade D Kraft paper) behind stucco, brick, stone and other porous veneers." While all this may be just a matter of semantics, I would have to guess that using the correct terms is indeed important in the scientific community.
Please see my BT post < Obsolete Link > More on Sheathing Wrap in the Construction Techniques subfolder for more information.
Re your actual question, I think you may find that a disadvantage of using asphalt roofing felt as sheathing wrap is the difficulty of sealing the joints. There are tape products that would probably do the job, but I think you will find them cost prohibitive. Check on Protecto Wrap's BT tape (about $11- 12 a 50' roll, or polykien tape (> $25 a roll) for possible solutions. Admittedly, asphalt roofing felt has a few advantages over housewrap too.
*There is no need to seal the #15 felt/tar paper.near the stream,ajIf you want to tape seal your house wrap then use a house wrap and house wrap tape!...KISS it
*FYI, latest JLC-journal of light construction has a comprehensive article on housewraps. Felt vs Tyvek vs kraft paper.
*Anyone had any experience with the "wrinkled" wraps they mention in that JLC article? Sounds useful to me if they really do let water drain out.I can't bring myself to go to the time and cost of furring out the siding to make a drainage plane as has been advocated in recent articles.Steve
*Matt g. Your critique of Fisette's paper is interesting. I don't know, off-hand,how many years ago(50?) felt was no longer made from rags.Yet we continue to incorrectly call asphalt soaked paper, " felt" and still assume it weighs 15 pounds per square.You note that you " would have to guess that using the correct terms is indeed important in the scientific community." Ah, if only this were so: While the majority of building scientists have switched from vapor barrier, to vapor diffusion retarder,a reading of ASTM proceedings on the subject finds no consistency in the use of vapor diffusion retarder. Vapor barrier manages to sneak in. I suppose the clerk at the local lumber yard knows what a vapor barrier is but has no clue as to what a vapor diffusion retarder is. Asking for a roll of 15lb. felt produces results, whereas, "gimme a roll of asphalt soaked paper" produces blank stares.But then what do you expect when Robin and Harvey, of the Discovery Channel's Gimme Shelter, tell millions of viewers that Tyvek and #15 felt are vapor barriers? GeneL.
*As I learned here from the late Freddy Lu, skip the 15# "tarpaper" and buy the Certainteed Roofer's Select. A whole different animal, really nice, hard even to tear ... yet it's humble 15# tarpaper.Steve, the wrinkled wrap sounds interesting to me, too. But if you are using lap or shingle siding is it necessary to have much of a drainage plane? If the siding is wood and needs to breathe, I've been curious about the plastic mesh "cedar breather" -- sheets of what looks like one of those kitchen dish scrubbers. This would also address another problem -- direct contact with latex backpriming may break down poly housewrap's water repellancy because of the surfactants in the paint. (Of course, you could always backprime with oil like you're supposed to....)Re the poster's Q -- I don't think making it airtight is all that important, nor that housewrap will stop serious leaks ... the air will find a way out. You could put a bead of sealant/caulk where the sheets lap. Better to stop the serious air leaks themselves? (Receptacle outlets, windows, etc.....) As you appear to suspect, Tyvek etc. have been oversold.
*Gene:I hadn't seen your post since I had forgotten to subscribe to this thread. Re your statement of ordering materials at the builder's supply, about a week ago I needed to order some cinder blocks. I called my sales rep who is extremely competent and always helpful. The block actually come from a local concrete block/RCP manufacturer but I can get it cheaper through my building supply. Anyway, my sales rep wasn't there so I left a message with his assistant. 4 cubes of 8" CMUs. Next day I get a call - CMUs? What do you mean by that. I explained that I wanted regular 8"x8"x16" cinder block!Re the Discovery channel, I havn't seen that program, but often when watching those type shows with my wife, I can be heard to mumble... "Who writes this $hi+"?
*MattI just read your response regarding housewraps vs asphalt felt. I'm about to put up cedar shingles on our house. The house is wrapped in typar housewrap. I'm thinking of using a felt paper over the typar "just in case". What do you think? Will two house wraps hurt? Will they trap moisture? I'm not worried about the expense of the second layer only the long term affects.Thanks for your help
*I can maybe see using 15# tar paper on a small house, but I just used over 2000 sq. ft. of housewrap on my house (9' x 150' rolls) and I can't even imagine what the labor would run to put up an equivalent amount of tar paper, especially 25' off the ground on the gables! For the record, Tyvek makes no claims to being a "vapor barrier." To the contrary, Tyvek says it lets the moisture diffuse to the outside, while keeping liquid water from entering from the outside. They claim a high "perm" number in fact.Do you need a vapor barrier? Debateable. Is Tyvek a vapor barrier? Absolutely not.
*the 15# felt goes up fast enough.. you put it up with the siding ... when you stage for the siding you put up the felt....doesn't take that much more time....
*Listen to Mike and myself...we have done it this way and are not just armchair quartebacking....right Mike?near the stream,aj
*well... actually aj.. i've never even seen felt.. never mind nailed it up.. or stapled it up.. or whatever it is those strong carpenters do.....but it seemed like the right thing to say... just wanted to encourage the man.....hah, hah,hah
*Put up enough myself for both of us....you armchair carpenter...Here's your slap!....near the stream,aj
*ok.. here's some Roofers Select being installed for Durapress siding...i'll show the rest of the fiber cement show in Construction techniques
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If you check Fisette's article, University of Mass, he concludes that tar paper/felt is best performer for house wrap.
http://www.umass.edu/bmatwt/weather_barriers.html
Anyone got any ideas on tapes or adhesives that would seal the overlapping joints in asphalt impregnated felt? Also, what do you use to seam seal OSB ?