How to Install De-Icing Wire on a Roof

Use a piece of chalk to lay out a pattern on your roof for the de-icing wire to follow. Begin at the edge of the roof, making a series of triangles that extend up onto the roof, with the peak of the triangles placed a foot past the point where the exterior wall intersects with the roof line. The base of the triangles should be 15 inches wide. Continue this pattern along any straight, obstacle-free sections of the roof edge.

Draw a loop that extends two-thirds of the way up the valley along the roof, leaving 2 inches of space between the chalk mark going up the valley and the mark coming back down the valley. Use this same technique for any areas where the roof line abuts an exterior wall of the house.

Extend a chalk line up and around the perimeter of any dormers, starting at the peak of the last unobstructed triangle along the roof edge. Follow the perimeter of the dormer, maintaining a 2-inch distance all the way around. Extend the chalk line across the front of the dormer, back to the last triangle, so that you can continue the pattern of triangles across the roof edge.

Extend the top of the triangle to within 6 inches of the edge of any skylights while still maintaining the 15-inch base of the triangles.

Install cable mounting clips to the shingles at every bend in the chalk line. Mount clips at the peaks and base of each triangle, at bends and turns, and every 3 feet along the cable for runs longer than 3 feet.

Lift the edge of a shingle and slide the spring clip onto the shingle, with the cable hook face-up. Press the shingle back down firmly.

Follow the chalk line with the cable, leaving enough slack in the beginning of the cable to reach the power source or controller for the heated cable. Press the cable into the hooks at the peak of the first triangle. Run the cable down to the base of the triangle. Leave enough slack for the cable to extend approximately 2 inches into the gutter and continue to the next peak. Continue this process along the roof edge.

Follow the rest of the chalk line, mounting the cable to the clips along valleys, dormer edges and abutments. Once you reach the end of the roof, route the cable back to the beginning by following the gutter. Extend a loop of cable down any downspouts along the gutter. Continue running the cable through the gutter and downspouts until you come back to the starting point.

Attach the wire in the gutter to the slack wire at the base of the triangles with the spacer clips. Squeeze the clips closed gently with a pair of pliers. Place a spacer clip horizontally in the cable clip on the edge of the shingle at the base of the triangle and place the loop that forms the base of the triangle in the two sides of the spacer clip. When finished, there should be a loop of cable coming off the edge of the roof, held by a spacer clip attached to the cable clip. At the end of the loop of cable, there should be a spacer clip that attaches the loop to the cable in the gutter. This provides a heated path all the way from the roof line to the gutter and into the downspouts.

Plug the cable into an appropriate power source or the controller once you've finished installing the cable and clips.