For you truss experts

[Shrimp92]

My plan is to have a stick building 40x50, trusses spanning 40'. They will be atttic trusses with a 14x8x50. My question: Can the truss co.use only 2x6s for the whole truss...I dont want bounce in the attic...How would you guys build a 40' span? Thanks for responses.

Pitch is 8/12.

 

[Red Goat]

I'm not a designer but I just had attic trusses built for my garage...span 26 1/2' with a 16' wide room. The designer spec'd 2x10 bottom cord and I ended up going with 2x12 bottom cords to limit the deflection. It is solid as Sears!

 

[brownbagg]

It is solid as Sears!

thats not saying much

 

[hansen1]

I span 36' with a 5.5 pitch. I have 12' wide room. Both my bottom and top are 2x10's. I built a very solid floor and it is feels as solid as the concrete floor. Mine are on 19.2" centers.

 

[PAToyota]

Rather than simply telling them sizes, talk to them about deflection. They can design it as solid as you want it.

 

[Red Goat]

It is solid as Sears!

thats not saying much

Should say "vintage sears"...

 

[DekeT]

How would you guys build a 40' span?

Would you build a floor in a regular room spanning 14 feet with 2 x 6?

 

[Shrimp92]

i had price ranges on trusses from 6300$ to $9100...6300 was all 2x6, 9100$ was MSR lumber measured for deflection

 

[Matt_G]

Attic trusses are a special truss, typically by code (where I am) the top chord must be at least 2x6 and the bottom chord must be at least 2x8. The floor size in the room will be similar to a joist in a house, so if you don't like the bounce with a 2x10 spanning 14'-0" the truss wouldn't work too well either. Also keep in mind a lot of the bounce is due to vibration, and that will depend on what type of sheathing (if your trusses are 24" o/c code here in Canada is you must use 3/4") and the blocking in the floor. What ever x bridging and bracing you would put in a typical 2x8 or 2x10 floor in your house you have to put in the floor of the attic truss. But talk to your truss designer they should be able to provide you with all the details and information you need. Also let them know if you are putting heavy stuff up there. Typically the floors in the attic trusses are run the same loading as your floor in your house.

 

[wssix99]

Rather than simply telling them sizes, talk to them about deflection. They can design it as solid as you want it.

+1. One could make a truss out of toothpicks that is stronger than one made of 2X6. Its all in the design of the members. If you are prescriptive with the truss manufacturer, they can meet your needs.

If you want to work and do things in the attic, your designer will need to know this. Normal trusses are often not built to perform in this way, but they could be. There are a lot of variables to consider: size of members, connections, fasteners, spacing, arrangement of members, shape, etc.