Labels:hakham | plant | sky | window OCR: Permeation Ratings Example ratings Gypsum 50 perm High Plastic Sheet Barriers 10 mil) 03 perm Low Lower perm Less Vapor Flow This slide gives an example of perm ratings for molecular permeation through buil Iding ma terials Note gypsum has relatively high permeance. has perm rating L depending upon core and facers Plastic sheet barriers like polyethyl lene have permeance as low as .16 to .03 depending upon millage. those cases you have very low permeation. Remember lower perm means less vapor getting through Slide AA Continuing Education Steel Stud Moisture Resistance XPS building relativel lyethylene Reinember oisture Resistancs
