It is our preference to lath all the roofs we install with 1x4 #2 Yellow Pine (YP) lumber. Doing so benefits in two ways. By installing the panel on top of the lathing we are creating a dead air space, which allows the heat that is radiated through the panel to ascend drawing cooler air in at the eave below. This prohibits the radiated heat from traveling down into the attic. This is a great energy saver while keeping the house cooler in the summer. Also, most new construction today is decked with Oriented Strand Board (OSB). The OSB will not allow the screws to be consistently or properly secured. The #2 YP has the required characteristics to hold the screws securely.