a hand - tearable barrier laminate includes a reinforcing layer having a first tensile strength . the reinforcing layer is laminated to a flexible cellulosic web . the web has open porosity and a second tensile strength which is less than the first tensile strength . the web is treated with a water - resistant polymeric resin for providing liquid water resistance to the web while permitting water vapor to pass through the web . this hand - tearable barrier laminate can be substituted for polymer foam and microperforated plastic films currently employed by the housing industry , reducing costs .