How to Build Rafters on a Patio Roof

A sturdy, long-lasting patio roof structure hinges on solid framework.

To begin the project, you’ll start by building rafters to support a patio roof with the following steps:

• Position the ledger board. The first step in attaching a patio roofto a house structureisto place the ledger board at the correct height, horizontal and level with the roof.The ledger board should be fastened securely in place with wall bolts or lag screws.
• Reinforce with flashing. As covered in detail in a previous chapter, metal flashing is necessary to waterproof patio roofing and protect the ledger board. Flashing should be installed against siding and bent over the ledger board, as well as over the face of the ledger board.
• Prep rafters. Before hanging rafters, it’s important to paint rafters and attach joist hangers.
• Hang rafters. 2’ x 6’ rafters can be attached directly to a house using joist hangers or fully supported by the ledger board. Rafters will be placed on 24” centers for full attachment to beams; settle joists can be attached where needed. Rafters are best hung working from each end toward the center of the patio roof. Each rafter should be leveled before attachment to the ledger and then settle joists.
• Finish with fascia board. After hanging rafters, rafter tails should be thoroughly checked to ensure that they remain in a straight line. If the walls of a house are crooked, it will also cause rafter tails to be crooked. If this problem cannot be avoided, use a chalk line to measure and trim rafters before attaching sheathing. Lastly, fascia board will be added to rafter tails to finish the roof structure.

This preliminary framing for a patio roof can be rated as medium to hard in its difficulty for a DIY contractor. It may take an entire weekend to finish creating rafters to support a patio roof. A basic DIY project of this kind could cost $1000 at the minimum.