Danfoss has introduced a roof clip that is the same as the other manufacturers:
They have a real nice installation guide it is linked below. It says DO NOT NAIL OR SCREW TO YOUR ROOF! They say to only use adhesive and to consult roofing supplier for recommended adhesives and specifically mention asphalt shingles.
088L3001 RX-C 50 Roof Clips
(50pcs in Bag)
The Danfoss RX-C Roof Clips are suitable for use with the RX-C Self Regulating Cables. The clips are designed to secure the cables to asphalt shingles, metal seam roofs, and gutters.
• caulking gun
• adhesive (see below)
• Shingles must be clean and dry
• Note adhesive application temperature limits
• Allow proper cure time for adhesive (typically 24 hours)
• Not recommended for rubber/membrane roof
• Do not use screw/nail with clip
• Consult roofing supplier for recommended adhesives
See roofing supply distributors for recommendations
1. Apply Adhesive:
• Apply 0.2 oz. of adhesive to back of clip.
• (Please note required application temperatures when applying glue.)
2. Press Clip to Roof Surface:
• Lift shingle & orient clip.
• Press down (ensure adhesive flows through holes).
• Do not trim back adhesive beads.
• Press shingle down.
3. Install Cables/Close Clamps
• Allow proper cure time (typically 24 hours- refer to adhesive.)
• Install RX-C de-icing cable.
• Use pliers to close clamps (ensuring not to damage cable).
• Roof clips must be installed properly to ensure proper operation and to prevent the risk of electrical hazard or fire. Follow all design, installation, assembly, and test instructions carefully.
• Arcing may not be stopped by conventional circuit protection.
• Do not use clip for installation on slate or tile roofs as damage may occur to roof material. Consult roofing manufacturer for components approved for use on specific roof material.
• De-energize all power circuits before installation or servicing.
• Keep ends of heating devices and kit components dry before and during installation.
• While using pliers to close clamps on heating cable, heating cable should not be crushed or altered structurally in any way.
• The cable should not be twisted during installation.
• Heating cable should not be embedded in the thermal insulation.