Hold the 1-by-4 lumber between two opposing rafters and place the level on top of it. Adjust the 1-by-4 until it is level and the bubble in the level's vial is centered. Loosen the wing nut on the bevel gauge and adjust the angle to match the angle between the 1-by-4 lumber and the rafters.
Place the bevel gauge against the side of the 2-by-6 lumber for the collar tie at one end. Transfer the angle to the end of the plank with a pencil and extend the line fully across the plank.
Cut the collar tie with the circular saw on the line. Measure from the point of the cut to the other end of the collar tie according to the length required and mark the same, but reversed angle cut at the other end of the plank. Make the second cut with the circular saw.
Hold the collar tie against the bottom edge of two opposing rafters with the level sitting on top of it. Adjust the collar tie until it is level. Drive one nail through each end of the collar tie from the bottom of the angled portion into the rafters to hold it in place.
Place a tie plate across the joint between the collar tie and the rafter on one side. Nail the tie plate to the rafter and to the collar tie using one nail in each tie-plate nail hole. Use all of the nail holes in the tie plate. Each collar tie requires four tie plates, one on each side of both rafters and the collar tie.
Things You Will Need
- 4-foot level
- Bevel gauge
- 2-by-6 lumber
- Circular saw
- Tie plates
- 10d 1 1/2-inch nails
- A better fix for sagging rafters is to reinforce the existing rafters with a second rafter nailed alongside the first. If an interior weight-bearing wall is present, adding kickers that support the rafters is an even better option. Install collar ties no lower than the height of the ridge beam divided by 3.
- The 2-by-6 lumber is sized accordingly for 2-by-6 rafters. Increase the size of the collar tie lumber to match the collar ties if necessary.