Drainage Housewrap

Abstract

A housewrap is a multi-layer drainage wrap. A nonwoven base web has a three-dimensional pattern embossed therein on one surface of the web. This embossed web is then extrusion coated with a polymer coating. The coating is extrusion-coated on to embossed side of the nonwoven base web. The nonwoven base web has the three-dimensionally embossed and coated side as its outward facing surface. The coated base web is then activated by stretching to provide moisture vapor permeance at a rate that allows a building to breathe. The result is a housewrap that is textured on both the inside and outside faces of the housewrap. The texture and weather resistive coating on exterior side facilitates both drainage of water off of the outside face of the housewrap and the circulation of air and moisture around and through the inside face of the housewrap and promotes a tighter seal and better adhesion to flashing tapes reducing further the points of entry for water into the structure.

1 . A drainage housewrap comprising:
 a nonwoven base web having a three-dimensional pattern pressed therein to form channels on a surface of the base web,   a coating bonded by extrusion coating to the surface of the base web after the three-dimensional pattern is pressed in it,   wherein the coating comprises a mixture of a polymer and calcium carbonate particles,   and further wherein the coated base web is activated by mechanical stretching of the coated base web in order to create micropores in the coating on the base web, and the thickness of the coated base web is from 0.015 to 0.05 inches;   and wherein the housewrap is impermeable to water but permeable to water vapor and air.   
     
     
         2 . A drainage housewrap as described in  claim 1 ,
 wherein the three-dimensional pattern pressed into the base web creates two sets of channels that are substantially perpendicular from each other.   
     
     
         3 . A drainage housewrap as described in  claim 1 ,
 wherein the polymer portion of the coating comprises polyethylene.   
     
     
         4 . A drainage housewrap as described in  claim 1 ,
 wherein the polymer portion of the coating comprises polypropylene.   
     
     
         5 . A drainage housewrap as described in  claim 1 ,
 wherein the three-dimensional pattern is in the shape of oval half-bubbles.   
     
     
         6 . A drainage housewrap as described in  claim 5 ,
 wherein the oval half-bubbles are positioned in alternating rows such that a long axis of each row of oval half-bubbles is perpendicular to the long axis of each adjacent row of oval half-bubbles.   
     
     
         7 . A drainage housewrap as described in  claim 1 ,
 wherein the calcium carbonate comprises 35-70% by weight of the coating.   
     
     
         8 . A drainage housewrap as described in  claim 1 ,
 further comprising flashing tape adhered to the coated side of the coated base web, whereby there is a continuous and complete seal formed between the flashing tape and the coated base web.