A T-shaped batt of insulation with a U-shaped vapor barrier covering the lower surface of the batt. The vapor barrier, which extends beyond the ends of the batt is used to connect consecutive batts. The T-shaped batts are installed by rolling them between parallel structural members so that the horizontal...http://www.google.es/patents/US4151692?utm_source=gb-gplus-sharePatente US4151692 - T-Shaped insulation with vapor barrier
