We don’t particularly care for this word. Images of silvery surfaces of raw meat, deteriorating layers of mystery substances, and dental-enhanced members of the band Cypress Hill shouting out their ridiculous, yet catchy, anthem “Insane In The Membrane” spring to mind. In the design sense, however, membranes are not nearly as disgusting and are, actually, quite important. In its most basic sense, a membrane is a thin, pliable (or semi-flexible) sheet of material that separates environments and prevents the transfer of anything between them. In the construction world, membranes usually act to prevent water from traveling where it’s not supposed to be, which tends to be on the interior of a structure. Therefore, these separating layers are used in roofing, exterior wall, and flooring assemblies to prevent moisture – whether trapped in a cement foundation or released from the heavens – from seeping into other materials, causing them to mildew, grow mold, and generally reek havoc on the earth. That’s a little dramatic, we know, but it does seem pretty serious when it happens to you.