Sometimes there aren't three

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Author Message Phil Kabza Senior Member Username: phil_kabza Post Number: 541 Registered: 12-2002 Posted on Thursday, May 15, 2014 - 05:14 pm:    Or even two. JLC sent this link to a brief video of a building wrap test that illustrates what we all should do more of: test stuff before we use it: http://www.jlconline.com/building-envelope/is-tyvek-worth-the-price-_o.aspx?dfpzone=general&utm_source=newsletter&utm_content=jump&utm_medium=email&utm_campaign=JLCNL_051514&day=2014-05-15 George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 742 Registered: 11-2004 Posted on Thursday, May 15, 2014 - 06:24 pm:    I am sure Casey Robb gives that video two thumbs up. George A. Everding AIA CSI CCS CCCA Allegion PLC (formerly Ingersoll Rand) St. Louis, MO ken hercenberg Senior Member Username: khercenberg Post Number: 751 Registered: 12-2006 Posted on Thursday, May 15, 2014 - 09:21 pm:    I suppose Tyvek is good as house wraps go, but for most projects I'll still opt for a good fluid-applied, vapor permeable air and water barrier like GE/Momentive's SEC2500 SilShield AWB - http://www.siliconeforbuilding.com/AWB/. Funny that the video and comments consider Tyvek Housewrap a water barrier and even a vapor barrier. It's neither. It's an air barrier. The fact that it has some capacity to prevent liquid water migration is nice. If you want an air and water barrier from Tyvek, try Tyvek fluid-applied WB system - http://www.dupont.com/products-and-services/construction-materials/building-envelope-systems/brands/air-barrier-systems/products/tyvek-fluid-applied-wb.html. J. Peter Jordan Senior Member Username: jpjordan Post Number: 725 Registered: 05-2004 Posted on Friday, May 16, 2014 - 07:34 am:    Sheet Tyvek was originally marketed as a weather barrier , a replacement for the #15 and #30 felts in exterior wall assemblies. A primary part of their marketing was that the product was breathable. While it was effective at preventing the passage of liquid water in the wall assembly, it was, and still is, highly permeable. It is not waterproofing, and as if old details are used, it isn't Alan air barrier. If your project is considering Tyvek, verify whether you need a vapor-retarding air barrier or a vapor permeable system. Continue to consider Tyvek if a vapor permeable product is required. Then review your details and specs to verify compliance with standards. Those details you developed six years ago may not be sufficient.