A clamp installable on a standing seam, comprising: a clamp body a pair of clamp body ends or end surfaces (108a, 108b) that are longitudinally spaced, a pair of laterally spaced and at least generally longitudinally extending clamp body side surfaces (118a, 118b), a clamp body upper surface, and a clamp body lower surface, wherein the clamp body further comprises a concave clamp body slot that is installable on the standing seam, wherein said clamp body slot comprises first and second open ends (124a, 124b) and first and second slot sidewalls (126b, 126a) that are disposed in spaced relation and that extend between said first and second open ends (124a, 124b); a first insert that is a separate piece than said clamp body, that is at least partially disposed within said clamp body slot, that is disposed against said first slot sidewall, and that is disposed in spaced relation to said second slot sidewall such that the standing seam is disposed between said first insert and said second slot sidewall when said clamp is installed on the standing seam; and a first seam fastener that extends through said clamp body, through said second slot sidewall, and within said clamp body slot in alignment with at least a portion of said first insert to direct the standing seam against said first insert when said clamp is installed on the standing seam and to place said first insert in compression; characterized in that said first insert comprises a first aperture that extends within said first insert and intersects with a second aperture, wherein said second aperture extends beyond said first aperture in a first direction which is at least generally parallel with a direction into which said clamp body slot extends from said body lower surface into said clamp body to define a first deflectable cantilever, and also extends beyond said first aperture in a second direction which is opposite said first direction and which is also at least generally parallel with said direction which said clamp body slot extends within said clamp body to define an oppositely disposed second deflectable cantilever. a clamp body a pair of clamp body ends or end surfaces (108a, 108b) that are longitudinally spaced, a pair of laterally spaced and at least generally longitudinally extending clamp body side surfaces (118a, 118b), a clamp body upper surface, and a clamp body lower surface, wherein the clamp body further comprises a concave clamp body slot that is installable on the standing seam, wherein said clamp body slot comprises first and second open ends (124a, 124b) and first and second slot sidewalls (126b, 126a) that are disposed in spaced relation and that extend between said first and second open ends (124a, 124b); a first insert that is a separate piece than said clamp body, that is at least partially disposed within said clamp body slot, that is disposed against said first slot sidewall, and that is disposed in spaced relation to said second slot sidewall such that the standing seam is disposed between said first insert and said second slot sidewall when said clamp is installed on the standing seam; and a first seam fastener that extends through said clamp body, through said second slot sidewall, and within said clamp body slot in alignment with at least a portion of said first insert to direct the standing seam against said first insert when said clamp is installed on the standing seam and to place said first insert in compression; characterized in that said first insert comprises a first aperture that extends within said first insert and intersects with a second aperture, wherein said second aperture extends beyond said first aperture in a first direction which is at least generally parallel with a direction into which said clamp body slot extends from said body lower surface into said clamp body to define a first deflectable cantilever, and also extends beyond said first aperture in a second direction which is opposite said first direction and which is also at least generally parallel with said direction which said clamp body slot extends within said clamp body to define an oppositely disposed second deflectable cantilever.