Field glossarySnap-lock vs mechanical seamSnap seams press together by hand; mechanical seams are folded closed by a powered seamerUsed across 2 Anvilfield field guides, most in Roofing. Where this shows upRoofingMetal roof types comparedRoofingStanding seam metal roof Related termsGalvalumeStanding seamExposed / through-fastener panel Back to the full field glossary