2x4 spanning question

[kylyo21]

I searched the net and couldn't find what I was looking for, sometimes I hate the internet!

Anyways I need to know if this design is okay. I got a 3 foot high center on a truss with about 9 foot 2x4's laying vertically (4" side up and down) from the floor to the peak. A basic right triangle with the longest side 9' and the straight up and down side 3'. Hope that makes sense.

With no other support in the middle of the span will that design be okay to not sag? I thin metal roof is going up top. I believe spacing of these "trusses" is every 18".

Thanks for any help

[busby]

http://www.awc.org/calculators/span/calc/timbercalcstyle.asp

[Silverback]

Do you get snow?
MOST trusses are made from 2" x 8" so you will probably be under rated.

[MANN]

I am going to assume that this is for a barn/shed/something small.

Your trusses need to be 16" or 24" OC spacing (that way the math works out with plywood/metal sheeting. I personally would use 16").

That will hold the weight fine, and will not sag assuming you dont get alot of snow, and dont plan on walking on them often. I have buildings built similar to what you are saying, and they are fine. Some of ours are actually longer spans, and do not sag (12' long 1:6 slope).

[DevilMan]

I also think that will be fine. A 9' run is pretty sure and a 3' rise over such a short run should be relatively steep so that snow and such will run off somewhat easily. IF you are overly worried about it, you could chop up a few more sticks or just get some shorties from the cull pile and make a support bisecting each side of the triangle therefore making 3 triangles. Run the ends down to touch in the middle so they are also pushing against each other.

I'm guessing you asked this though so as to know whether or not these are needed. I'm not an expert but over such a short run, and if you run them on 16"OC I think you'd be fine.

DM