Building Wraps /Houswraps
Building Wraps /Building Envelopes /Housewraps
Polymer coated papers and water resistant sheathing materials are known to be useful in the construction industry, for preventing the infiltration of air and water to the interior of a building while allowing the outward passage there through of moisture vapor. Such materials may be flexible and used as building "wraps," or may be rigid and used as structural or decorative panels in the exterior walls or roofs of buildings.
Breathable building wraps, also referred to as housewraps, are used and provide advantages in the construction of wall and roof assemblies. These housewrap materials improve energy loss through reduction of air infiltration as well as acting as a weather barrier by preventing water intrusion into the building. It is a requirement that these materials are breathable, as defined by a minimum level of water vapor transmission rate (WVTR). Two popular materials that are manufactured for housewrap that achieve the combination of a barrier to water intrusion and air infiltration while remaining permeable to water vapor are a flash spunbonded polyolefin that may be obtained from DuPont under the name Tyvek..TM.. A second material is a microporous polyolefin film composite and may be obtained from Simplex Products under the trademark "R-Wrap.TM." Besides the popular brands, there are a variety of other brands such as Typar.RTM. from Reemay, Amowrap.RTM. from Teneco building products, Barricade.RTM. from Simplex, PinkWrap.RTM. from Ownes Corning and others.
Recent US Patents
11/16/2011
7,833,916
Energy efficient and insulated building envelopes
Leeser et al of Aspen Aerogels, Massachusetts, have developed several methods and materials for use in building construction that may require air and water barrier, and water vapor permeability along with thermal or acoustic insulation. One example is permeable to water vapor laminated to an aerogel insulating material. (RDC 3/30/2011)