How to Install Rafters on a Brick Wall

Remove the roofing material, insulation and flashing from every edge of the roof surface. Use your crowbar to pry away each layer of materials. The idea is to reveal the ends of your ceiling joists, which are constructed of two-by-four studs. The ends of the ceiling joists must be removed so that a length of two-by-four can be installed on which the rafters will rest.

Snap a chalk line across the joists to mark the cutoff line. The cut should allow enough room for the two-by-four to fit onto the top of the brick wall so that it sits flush with the outside brick. This wall plate will also lend support to the joists so that the cutting you perform does not weaken them structurally. Use your level to ensure that the line is perfectly plumb from end to end, and use your circular saw to make the cut.

Apply a coating of concrete to the top of the brick wall where the wall plate is to be installed. Place the wall plate onto the concrete and press it into position. Use your level to ensure that the plate sits perfectly level, then use your power drill to make pilot holes through the plate and into the joists behind. Drive one roofing nail per joist using your hammer.

Install steel L-shaped corner brackets on each side of each joist where it meets the wall plate. Use your screw gun and decking screws to fasten the brackets in place. These brackets will add extra support and prevent the wall plate from shifting side to side. Repeat the wall plate installation process along the opposite wall as well. Allow the concrete to dry according to the manufacturer's instructions before proceeding with the installation.

Cut notches in your 2- by 6-inch rafters so they sit at the proper angle atop the wall plate. Place a length of 2- by 6-inch lumber onto the wall plate and use your pencil and straight edge to extend the outside edge of the wall plate upward and onto the wood about 2 inches. Use your carpenter's square to make a second line on your rafter at a right angle to the first and toward the inside edge of the wall plate.

Cut the notches using your circular saw. Place the rafter onto the wall plates. Then drive roofing nails down through each rafter and into the plate below. Repeat the process along the entire length of the wall.