NAC ECB Crack Isolation Membrane (150 SF/Roll)ECB is a 40 mil thick (approx. 1 16") sheet applied membrane designed for use under floor surfaces that require protection from structural movement. ECB provides protection for up to 3 8" of lateral structural movement and is an ideal solution for malls, airports, apartments, condominiums, multi level hotels, high rise office buildings and any commercial or residential installations that require crack protection. For full floor coverage and soft joint