Hom tshiab ntawm cov khoom siv dej tsis zoo muaj kev ua haujlwm siab ntawm kev tiv thaiv permeability, dej-pov thawj, thermo-stability thiab cryogenic cov cuab yeej, siab zog thiab elongation thiab muaj cov yam ntxwv ntawm kev laus tsis kam, yog dav siv rau waterproof hauv tsev ru tsev ntawm kev lag luam thiab kev tsim vaj tse, underground, qhov, av dag, thiab lwm yam.