My neighbor is getting ready to build a new house located in upstate NY. His question pertains to housewrap. When I built my house 5 years ago it was Tyvek in 9′ rolls all around. Recently there have been articles about the internal moisture retention in the walls and subsequent rotting (although I recall them being few and far between).
So what are the thoughts from you on Tyvek vs. the old 15# felt paper, is there also a new product out similar to Tyvek but has a weave that will allow moisture to escape?
Any help is appreciated.
Replies
I dunno, but in my area (south eastern US, I bet 40-50% of the houses going up, from 100 to 300k, are vinyl over the sheating, no wrap at all. Even tho code calls for it, even the code dept overlooks this
I work for a framing sub and this question has come up alot. I live and work in souther oregon where it's wet more than half the year. We have 2/3 of our generals ask for some type of house rap, the others don't think its needed. two yeas ago the county inspection department decided to "no longer condone the use of house rap". If you have it on they don't care, but you will pass inspection without it.
I would put it on my home, I don't plan on having buckets of water in my walls.
You should check for house rap made by a company called DOW, we have it around here and some people really like it.
Not using some form of moisture barrier is, in my opinion, incorrect and irresponsible !! For the few bucks it costs, it (wrap or felt) will not only keep moisture from the substrate, it provides an air barrier also.
Ken in Savannah
I'm a GC in SW Oregon and if your inspector is not requiring a vapor barrier, he is ignoring code.
I don't want to be giving out bad info, your responce concerns me. I was only going off what I have seen and heard. I work in the city of Grants Pass and the county of josephine. Sounds like you might be near here. If this is really a code issue it neads to be addressed.
I'm in Coos County on the coast, but the CABO code is the Oregon statewide standard. There are, of course, exceptions to the state code requirements in city jurisdictions, but they often exceed the state standards, or have jurisdiction-specific requirements such as setbacks, zoning, elevations of buildings, fencing standards, etc., that wouldn't be a concern in a rural area.
So, to begin your inquiry, I refer you to Section 703, EXTERIOR COVERING, paragraph 703.2 Weather resistant sheathing paper.
There are exceptions where a vapor barrier can be omitted listed in paragraph 703.2.1.
Perhaps your observations are of structures falling under that last paragraph so check it out before you start raising a ruckus! :-)
I have the impression that you're one of the up and coming hardworking worker bees so I'm giving you just some basic info so you'll have to do a little research.
Getting acquainted with the code book will be of benefit to you in the long run....
Let me know what you find out!
You're talking about two different things - house wrap/ tar paper and vapor barrier. In a cold climate the vapor barrier should be inside the wall. Any wrap/paper on the outside needs to be able to diffuse water vapor out. I think it's a bad idea to put 1" foam board on the outside of the wall, especially over OSB, as any vapor will condense on the interior side of the foam and soak into the wood.
I am in SE Michigan and it gets cold. I argrued that we should have 15# felt between the OSB and the foamboard but listening to Dow Chemical, the manufacturer that is also in Michigan, they wouldn't recommend the felt. So I left it off the house, we won't know the results for a few years.
Dog,
The Dow Weathermate housewrap is some pretty good stuff, but it's very heavy and slick--it tends to "slip" under the grip-cap nails. I've also used "R-Wrap" from Ludlow Coated Products and I really like it. Stay away from Polar Wrap (I think that's the name); it is junk.
Does anyone believe that vinyl siding is waterproof? I am very willing to try new things, like I-joists, LVL's and OSB but I have a tough time NOT using some type of housewrap. I prefer 15# felt but is it allowing the walls to "breath". I am in SE Michigan, lots of Tyvek. I am working with Habitat for Humanity and we added 1" T & G Dow board to a house with 2X6 walls. Dow claims that the Dow board forms the moisture barrier, when taped with their tape. I used 15# felt to flash the windows and doors. I am learning that as we build tighter houses that there is a need to dispel the moisture. Bath fans & kitchen fans MUST vent outdoors (it's code) and we must do a better job at sealing up scuttle holes in ceilings, using perimeter sealant at rim boards and at base of walls before siding. Expelling airborne moisture from walls correctly and interior air quality are important issues that are NOT being addressed enough or they are not getting the national forum required. We, as builders, are relying too heavily upon manufacturers and their sales reps to answer our concerns.
why does not habital use hardie plank - seems its cheaper, holds up better, and requires less mtn, and looks good?
I have seen rot under tyvek when there is snow buildup against the wall for a good part of the winter. This often happens when there is a metal roof and the unloaded snow builds up to great depths. This is in the Sierras near Truckee Ca. Condensation occurs inside the tyvek from the cold surface on the outside meeting the warm inside. There could be some capillary action too. For some reason there is not as much condensation and rot under felt paper.