Only positives come from restoring a coating on a metal roof and then maintaining that coating by re-coating the roof as necessary. An elastomeric acrylic coating acts like a shield, protecting the metal roofing system from the elements, including ultraviolet (UV) radiation, and ice and hail storms.
one hand clapping. The sound of one hand clapping is the sound of one hand closing quickly. The sound of one hand clapping is supposed to be a question with no answer. It is a clasic Zen koan given to students to aid in enlightenment by leading the mind into a cul-de-sac with no way out but enlightenment.
shake sb's hand/shake sb by the hand. B1 to hold someone's hand and move it up and down, especially when you meet them for the first time or when you make an agreement with them: Pleased to meet you, he said, shaking my hand. Congratulations, she said, shaking the winner by the hand. shake hands.