IKO added a fine-granule strip to Cambridge shingles to reduce bundle distortion during storage. The bulletin explains that its width can vary and it is hidden after installation
IKO technical bulletin: TBR73 Sand Strip | Product Bulletin.
What this means for your roof
IKO added a fine-granule strip to Cambridge shingles to reduce bundle distortion during storage. The bulletin explains that its width can vary and it is hidden after installation. It specifically warns against treating that strip as the nailing zone. Nails must follow the product instructions and penetrate both laminated layers in the required location.
A useful question for your contractor
Are the fasteners on the specified nail line rather than the sand strip?
Ask for the answer to be tied to the actual roof condition and the exact product being installed. Keep the agreed repair or installation detail with your estimate and project photos.
Bulletin dated: July 2012. The date shown identifies the manufacturer document used for this summary.
Read IKO: TBR73 Sand Strip | Product Bulletin
This homeowner summary explains the cited bulletin. The complete manufacturer document and current product instructions govern the installation details. A requirement for one manufacturer or product should not be transferred to another without checking.
Discuss your roof with Barnes N’ Roofs
Cover image: IKO, from the linked manufacturer bulletin. Read the complete source for the full detail and its limitations.