Safe Loading for Wood Truss 1

[dmx]

I have 2x4 wood trusses 2'-0" O.C. spaning my garage that support the garage roof. The span is approx. 21 feet. The ceiling of the garage is finsihed with 1/2 drywall. The truss manufacture said that the bottom cord was designed for 10psf DL and 0psf LL. The top cord is designed for 10 psf DL and 35psf LL. I would like to use this area for some storage. What I would like to know is what loading (psf) can I safely put in this space, and if I needed to add some additional support....what would be the best way to do it. I was thinking of getting some 2x8's @ 12' long and spaning the garage walls between the trusses and lap-splicing them together.

Thanks,

DMX

 

[boo1]

I have use very light (~10 PSF) loading with no problem before (loading increases reflection=nail pops). For 10-20 PSF loadings double up the bottom cord with 2x4 on both sides or one 2x6 attach to cord. Ensure the joint is not at center span, where bending moment is highest.

 

[Trussdoc]

Truss suppliers make money by putting the minimum amount of material into the truss as needed to support the design load. The metal connector plates may or may not be adequate to support more load, even if you reinforce the wood to carry it. I would think that on a short truss such as yours, the plate size is determined by the smallest size available, rather than by the design load, giving you a little bit of excess capacity in the connection.

If you install a larger dimension bottom chord reinforcement with an adequate splice, you could consider the bottom chord as acting as a beam or joist, and the connection issue becomes moot.

 

[dmx]

Thanks for the help.