Don Vandervort, Head Homeboy, has written more than 30 DIY home improvement books, been a segment host on HGTV, served as MSN.com's home improvement expert and written countless magazine articles.
Rafters spread roofing loads across beams, making it possible to use roofing materials too thin to span the distances between beams.
Rafters must support their own weight over open space without sagging or twisting and also support the weight of the roof covering. For a roof that must shed water, they are sloped.
Rafter Construction Rafters may connect to ledgers and beams any of several ways. The right method to use depends on the roof's design.
Attaching rafters to a ledger. With a house-attached overhead, rafters are fastened to the house at one end, as discussed HERE. Metal framing connectors make the best connections. J
Joist hangers can hang rafters from a ledger, but notch the rafters or use special rafter hangers for sloping rafters. If rafters will sit on top of a ledger, attach them with seismic anchors as you would attach rafters to a beam.
Splicing rafters. Where rafter connections will not be visible, rafters can be spliced together end-to-end with board lumber "gusset plates." To do this, butt the ends of the rafters together over a supporting beam. Then nail two pieces of 1-by or 2-by lumber of the same width as the rafters (see left) and about 18 inches long centered over both sides of the splice. Or, join the members using manufactured metal splice plates.
Be sure each rafter end sits a full inch on the supporting beam. If you must splice several rafters, stagger the splices over different beams to prevent a weak substructure.
Another splicing method—though it does not utilize uniform spacing—is to overlap the rafter ends that are supported by beams. If more than one splice is needed on a full rafter length, alternate overlapped sides.
For standard 2-inch lumber, nail both faces of each splice with six 8d or 10d common galvanized nails. This type of splicing, as shown above right, adds lateral stability to the rafters and may eliminate the need for bracing.
Patio Roofs & Gazebos All you need to know about building outdoor structures, from an inspirational gallery for unique ways to extend your living space outdoors, to step-by-step photo sequences to build an outdoor structure precisely suited to your needs.
