Modifying Roof Trusses

Click here to get free fast bids from local structural engineers who can help you modify your trusses.

Modifying roof trusses.

These trusses are usually engineered by a structural engineering company to carry a specific roof load. You can modify the trusses but it s an enormous amount of work. 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. Measure the width of your roof trusses from inside to inside.

While this article focuses on configurations we also have a very cool set of illustrations showcasing the different parts anatomy of roof trusses. 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. 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. Trusses must be modified to allow room for attic space.

If you live in a house with engineered manufactured trusses then don t mess with them. My recommendation is really simple. If you modify the existing trusses i have one suggestion. Also if you decide to do this you must work hand in hand with a licensed structural engineer that s familiar with wood trusses.

If a lot of trusses are damaged or one has been significantly modified or cut then consulting a engineer is wise. While they look the same you probably didn t notice the subtle differences. The lower cord or joist forms the lower horizontal of the triangle supporting the attic floor and top floor s ceiling. If you really want to modify the framing of your attic and roof then consult with a licensed professional structural engineer.

The upper cords or rafters form the peak of the roof. Rather than trying to make a scissor truss do a raised center. 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. When a truss becomes damaged cut or modified there is a chance of a structural overload or that they will not perform properly.

Don t modify cut wood trusses. Most common attic trusses for homes and garages are made with 2x4 s. If the house is new enough that you know how built the trusses give them a call. To do this i d have to cut out and raise the bottom chords of the trusses.