Snow brackets are installed on many roof types. They can be installed (depending on the type of bracket) at new construction and also retrofit. Brackets are extremely strong, they're made to hold the snow all in one glacial blanket of snow. Snow brackets are installed in a staggered pattern across the entire run of the roof and up to the headwall or ridge of the roof. Please contact Sales@trasnowandsun.com for an engineered layout for your project for free!