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.

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