I want to cut the trusses above my garage what do I need to know?

Question

I am assuming you just need to make sure they're not load bareing before you cut anything. I want to bolt 2x6's from the bottom of the " W " to the roof. Then bolt 2x6's across the top of the peak about 3ft down. Then the part that isn't load baring anymore cut out so I can have strait up walls like a bonus room over the garage but just for storage. Can I do this without the gargage roof sagging, or violating a code. If I go to sell my house I don't want an inspector to say this needs to be taken down and repaired.

Answer 1

If this is a true engineered truss, then be very careful about changing its design. A truss is a complex arrangement of interconnected triangles which share and spread the load from the top plates (hypotenuse) to the ends, where the load is transferred to the walls. Trusses are designed to be both strong and economical - the design engineer tries to use the least costly lumber in a cost-effective design to make the strongest truss design. Removal of any piece of a truss will seriously compromise its integrity.

As to load bearing or not, the load carried by a truss is your roof. It is not optional and you will not find a non-load bearing truss in your entire roof - every truss carries a part of the roof load. (If a truss was non-load bearing, why would the builder install it???)

Having said all this, if you are still determined to modify your trusses, contact a licenses structural engineer to review your truss design, roof design and static and dynamic load conditions (wind, earthquake, etc.) Then he or she can determine if you can make any changes. In my opinion, you will get a negative response.

Good luck.

Answer 2

All trusses are load bearing.

If you have site-built rafters (rare in modern residential construction) then you might be able to do what you have in mind. But with manufactured trusses, any modification will compromise their strength. They're built in that "W" configuration for a reason -- to properly distribute the weight of the roof to hold it up, and to hold the roof down during severe winds.

If all you need is additional storage you'd be better off adding a lean-to against the garage wall or putting up a shed in the back yard. What you have in mind will require hiring a structural engineer before starting, and his fee alone is going to be more than a little extra storage space is worth.

Answer 3

Don't modify trusses, without professional help. Trusses are specifically designed for the loads the carry. That a truss does is convert bending stress in to axial stress that either are compression or tension. The top cord is in compression, the bottom is in tension. The middle cords or webs are either in compression or tension, depending on placement and angle to the top and bottom cords. Because the loads on the individual cords are essentially axial, they can be slender 2x4's. If you were to modify the trusses, and remove the bottom cord, the bottom would likely begin to spread out. Even with some reinforcing, the members that were designed for axial loads are now being forced to carry bending loads.

What you are attempting to do can be done, though. But you shouldn't do it until you contact an engineer. And get detailed instructions on what structural members that need to be added and what type of connectors you need.

Answer 4

You could do that. But it is a bit expensive and does not have a very high R value. Because it is a garage I doubt that there are fire blocks in the wall. Is there any gaping toward the top of the sheet rock? If not, you could still take a utility knife and cut 6 inches off the top of the whole wall. Then blow in the insulation and put back up just a 6 inch strip of drywall. I lived in a neighborhood of old houses which didn't have insulation. There were many ways that people were insulating their walls. One was to pop off a small amount of siding from the outside, blow in the insulation then pop the siding back on. Another was to use the "Great Stuff" liquid insulation. Some professionals have this in large industrial sizes. They can blow that stuff into holes only a half inch. Just some thoughts. Good luck

Answer 5

In order to determine which trusses are not load-bearing, you'd do well to hire a professional engineer.

You can guess which ones aren't load bearing, but I'd make sure my affairs were in order and a copy of my will was easily found before making the first cut.

Answer 6

Everyone here is correct! Any engineer who might touch this would be suspect as well as costly. Trusses are designed the way they are to do only one job, hold up the roof. Any modification would jeopardize your belongings and negate any claims to your insurance company.
Please don't pursue this.

Answer 7

all trusses are load bearing, dont do it,, you will be in for a big shock