Modifying Roof Trusses

Measure in from the lower edge of the roof to a point 1 4 the width of the truss on either side of the attic.

Modifying roof trusses. The upper cords or rafters form the peak of the roof. If you live in a house with engineered manufactured trusses then don t mess with them. Use a chalk line to draw a line along the floor parallel to the lower edge of the roof from one end of the attic to the other on both sides. If you really want to modify the framing of your attic and roof then consult with a licensed professional structural engineer.

Also if you decide to do this you must work hand in hand with a licensed structural engineer that s familiar with wood trusses. Let s compare common roof trusses with the roof framing materials that were used in your parent s house. Just as there are many types of roofs with many roof parts there are many different types of roof trusses this extensive article explains through a series of custom truss diagrams the different truss configurations you can use for various roofs. The lower cord or joist forms the lower horizontal of the triangle supporting the attic floor and top floor s ceiling.

Trusses must be modified to allow room for attic space. Don t modify cut wood trusses. Modifying roof trusses my client wants to add a 16 inch wide 4 inch deep tray ceiling in a room where the drywall ceiling is attached to the bottom chord of roof trusses. Rather than trying to make a scissor truss do a raised center.

When a truss becomes damaged cut or modified there is a chance of a structural overload or that they will not perform properly. Your parents roof rafters were probably made from 2x8 s and could have been 2x10 s or. While this article focuses on configurations we also have a very cool set of illustrations showcasing the different parts anatomy of roof trusses. To do this i d have to cut out and raise the bottom chords of the trusses.

While they look the same you probably didn t notice the subtle differences. My recommendation is really simple. If the house is new enough that you know how built the trusses give them a call. These trusses are usually engineered by a structural engineering company to carry a specific roof load.

If a lot of trusses are damaged or one has been significantly modified or cut then consulting a engineer is wise. Click here to get free fast bids from local structural engineers who can help you modify your trusses. If you modify the existing trusses i have one suggestion. That way the last few feet at each end of the truss will not have to be modified and the changes should be less extensive.