What is a metal ridge cap in construction?how to make a roof ridge cap? The series of ridge cap roll forming machines are mainly used to make ridge capping. Ridge capping is a critical part of the structure of a roof. Ridge capping is placed along the peak of a roof to cover where the roof sheets meet. Roll-top ridge capping is a rolled product that is made to specific dimensions and cut to requested lengths. We manufacture both standard size ridge capping roll forming machines and customized roll forming machines.