Cut Truss Roof

Anthony DiStefano is an inspiration for all of us. He lives in Ocala, FL, and loves to work on cars. 

"I watched your video and I was wondering if you would give me some off-the-record advise about my garage idea. We have a 3 car attached hip roof CB constructed garage, W-trusses running front to back (24' 6") including 2' overhang on front and back.

I want to install a car lift for my classic car. I am 75-years old and I am tired of lying on my back while I complete my restoration and service. The middle bay is where I want to install the 4-post lift.

Looking at the garage their are 11 trusses from left to right. At the 11th truss is where the hip roof starts for the right most car. I would like to modify the 8th and 9th truss only, remove middle section (6') of the bottom cord ( middle of the W) and raise it 2'.

I would add an additional full bottom cord 2' higher making a smaller W (see my drawing). This would give me a 6'x6' rise of 2' for the cars roof. The rise from the bottom cord to the peak is 69 inches."

Here's Anthony's proposed solution.

Anthony, I applaud what you want to do and off the top of my head I think you can make this happen.

But, there's always a but.

It's considered a major No-No to alter prefabricated trusses.

These structural members are engineered for the exact situation and the framing lumber used in them is sized for the point loads in the design.

That said, it's possible you can get away with doing the modification you want to do.

I would take your drawing and some photos of your roof and attic to two local truss manufacturing plants. They all have an engineer on staff and because of your age - it's an advantage here! - they'll probably be all too glad to tell you what you can do.

If that doesn't work, you'll need to hire a residential structural engineer that will give you a drawing of what you can do and exactly HOW to do it.

If your drawing is approved I can tell you how I'd do it. I'd install TWO new bottom chords - one on either side of the truss members. I'd attach it to the sloped top chord with three 3/8-inch through bolts. The holes for the bolts MUST be 3/8-inch so you have to hammer the bolts through the lumber. You can use nails - 16d sinkers - at all the webbing connections.

But realize I'm NO ENGINEER. Get the solution and fastening suggestions from pros.