Q. We’re framing a gable-roofed house with roof trusses. The roof includes a bumpout with a smaller gable roof that intersects the main roof, forming two valleys. A valley set will be installed on top of the main roof sheathing. The sheathing along the valley doesn’t have blocking for continuous nailing, and I’d rather not nail sheathing to sheathing. Should I install blocking between the framing members of the valley set to provide better nailing?

A.Don Richardson, president of the U.S. Division of Romaro Structures, a truss manufacturer, responds: Installing blocking is not necessary, since the sheathing in a valley doesn’t need to be nailed between framing members. The same situation occurs at a ridge; although a truss roof, unlike a conventionally framed roof, has no ridge board, no blocking is necessary at the ridge. Contractors who feel more comfortable with blocking can always install it, but it is unnecessary.