Exterior Insulation Finishing System (EFIS) is an exterior wall system used on buildings to provide an insulated finished surface that is also waterproof. EFIS is a proprietary system and must be architecturally designed and installed to function properly. EFIS is attached to the outside area of exterior walls using an adhesive. No mechanical fasteners are used to secure EFIS as this may cause unsealable holes which will not allow the EFIS to be water proof. EFIS was created in Mexico after World War II to cover over solid masonry walls. Becoming popular in 1970’s during the oil embargo, EFIS is an energy efficient wall system.
