How to Build a Pitch Truss

Layout

• 1

  Mark out a line using a chalk line that measures a distance as wide as your roof will be. Do this on a concrete surface. Make the line as long as the width of the walls, plus provide for at least 1 foot of overhang on each side of the structure.

• 2

  Find the center of this line with a tape measure and mark that point with a stick of chalk. Measure up from this point to a second point that is as tall as the roof will be above the tops of the walls. Mark this point, which represents the roof's peak. Divide the height of this line in inches by half the length of the base line in feet to find the pitch.

• 3

  Use an online calculator (such as the one from the resource section of this article) to translate the pitch into an angle. Follow the instructions to enter your rise into the appropriate space. The answer the calculator gives you will be used at the ends of the upper and lower cords, and the top of the king post.

• 4

  Measure the bottom line of the chalk diagram from corner to corner. Cut a piece for the bottom horizontal section, known as the lower cord. Cut it from 2-by-4 lumber. Cut the ends of the piece mitered at the angle calculated by the online calculator. Make the cuts one right and one left, angled in toward the center to form a trapezoid.

Assembly

• 5

  Lay the lower cord along the chalk line so that the bottom edge of the line is aligned to the bottom edge of the board. Measure from the peak mark to the top corner of this board and cut the upper cords from 2-by-4 lumber to that length. Cut the ends at the same angle you used for the lower cord.

• 6

  Fit the upper cords in place, so that the top ends meet together to form the peak, and the lower ends rest atop the upper edge of the lower cord with the outside edges aligned.

• 7

  Find the the center of the lower cord width-wise with a tape measure. Measure up from the mark to the underside of the peak. Cut a piece of 2-by-4 lumber, to that length by using the miter saw. Mark the center of one end. Cut the corners of that end off at the same angle you have been using, to form a peak on the center mark. Fit the piece so that the flat bottom end rests on the top of the lower cord and the peak you cut on the board fits inside the peak formed by the upper cords.

• 8

  Trace the joints onto 12 inch squares of 1/2-inch thick plywood. Make two pieces for the peak joint between the two upper cords and the vertical center support, known as the king post. Trace two for each lower corner and two for the joint at the base of the king post.

• 9

  Apply wood glue to these plywood gussets and staple them to the face of the truss. Turn the truss over and staple plywood gussets to the rear face to stiffen them as well.