An assembly for fastening a conduit to a flashing structure that is typically secured to a shingled roof. The apparatus includes an adjustable clamp that can be secured to a cap on the flashing. A conduit is laid on top of the cap and the adjustable clamp is positioned on top of the conduit and is snapped in place along the perimeter of the cap. An adjustable bolt is threaded through the top of the clamp with a curved saddle that resides beneath the clamp and conforms to the shape of the conduit's outer surface. The bolt can then be adjusted to tighten the conduit to the cap. An exemplary use of the clamp involves securing conduit for running electrical wiring throughout a solar panel array.