From Klober
The Dry Bonding Strip is an excellent way of providing a mortar free, watertight junction above the party wall between different roof finishes when re-roofing. Area of application For slate, flat & plain tiles Key Features Provides a weather tight junction between differing roof finishes. Lightweight and flexible to handle for a safe and easy installation. Mortar free and easy to cut. Fire tested to comply with BS476: Part 3 SAB andPart 7 Class 3.