How to build a wooden roof truss

Updated February 21, 2017

Trusses come in a variety of different shapes and sizes, depending on the type of roof construction. Roof trusses are framed for simple gable, gambrel, cathedral or attic roofs. A residential roof truss can measure anywhere from 15 feet to 50 feet long and be as high as 5 feet to 15 feet. The size of the truss depends on the length and height, or roof pitch and span plus any cantilever if applicable. Because of new technology and ease in preparing and using roof trusses, most new houses are built using trusses.

Locate a large open area outside. The roof truss is constructed lying down. When it is finished, it is tilted up and secured in place on the roof.

Set up a table saw. Most of the roof truss 2-by-4 lumber will need to be cut to size. Once you measure and mark the lumber, cut it all at once so it is ready for construction.

Position a 24-foot piece of 2-by-4 lumber as the bottom chord of your truss. Make a triangle out of two 18-foot pieces of 2-by-4 lumber that connect at the top peak and overhang the bottom edges of the bottom chord about 6 inches.

Attach the two top chords at the peak with a metal gusset, and attach the bottom ends of the two top chords at the bottom chord with metal gussets. Use 8-penny nails to secure the gussets to the wood.

Prepare two webs 7 feet long. The webs are pieces of 2-by-4 lumber positioned between the top and bottom chords for support. Connect the tops of the two webs to the peak using 16-penny nails hammered in at angles. Connect the bottoms of the two webs to divide the bottom chord into thirds. Use gussets to secure the webs to the bottom chord.

Cut two more webs both 3 feet long. Attach the bottoms of these webs to the same gussets at the bottom chord that the longer webs are attached to, and attach them to the centre of the top chords, one on each side.


When laying out your roof truss, after your lumber is cut to size, you will need to make angle cuts on the ends of your webs so they lay flush with the lumber before they are attached. Simply mark the angle with a pencil and a straight edge, and cut through the line with your table saw.


Wear gloves to protect your hands from the sharp blade on your table saw, and wear googles to protect your eyes from flying lumber.

Things You'll Need

  • Table saw
  • Tape measure
  • Pencil
  • 2-by-4 lumber
  • Hammer
  • 8-penny nails
  • 16-penny nails
  • Gussets
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About the Author

Lacy Enderson is an Addictions and Recovery Counselor. She is Certified with the American Association of Christian Therapists and holds a Master's Degree in Biblical Counseling. She is currently enrolled in Liberty University's Master of Divinity Degree program with Chaplaincy. Lacy is a graduate of Rhema Correspondent Bible School and has completed the first section of Berean School of the Bible. Lacy is the author of, "Addiction: A Personal Story" and "So You Want to Lose Weight But You Can't Stop Eating." Her newest novel is a teenage Christian fiction titled, "Honey Sweetheart."