Truss bottom cords?

[jaybird3897]

Can I mix 2x6 and 2x4 bottom cords without issues as long as pitch is the same? I plan on using half scissor trusses with 2x4 bc and half storage trusses with 2x6 bc on a 30x48x10.

 

[DekeT]

You can use whatever you want as long as its designed to carry the load.

 

[theoldwizard1]

You can use whatever you want as long as its designed to carry the load.

That means approved and stamped by a certified engineer !

 

[Jayboh]

I've seen trusses come from the plant with do not use scribbled across them in marker. In Florida framing they use a lot of number 3 syp to build the trusses. Then set em two ft oc and use 7/16 osb to deck. The result is awful, but the way the truss is designed it keeps its structural integrity even though the lumber is garbage.

 

[jaybird3897]

Sorry, what I meant was by mixing different sized base cords will my top rafters still come out even for putting on roof as long as pitch is the same?

 

[BFBOB]

Sorry, what I meant was by mixing different sized base chords will my top rafters still come out even for putting on roof as long as pitch is the same?

Fixed it for ya!

 

[BFBOB]

I'm guessing the difference in the height of the bottom chords would be taken up inside the truss structure, not added to the bottom, but that's just a guess. You need to check:
IF the roof pitch is the same AND the height of the roof above the point where the trusses sit on the wall is the same, yes. You'll have to look carefully and measure scale drawings or measure the actual trusses. If one style sits higher, you'll have to shim the wall where the shorter ones will sit. A full length shim (same as just building the wall taller to begin with, or making a double top plate) should be done, even if it's not required.

 

[Thumper68]

Just tell the truss manufacture what you are looking for, they will set them up to do what you want.

 

[Garage Dog]

I'm guessing the difference in the height of the bottom chords would be taken up inside the truss structure, not added to the bottom, but that's just a guess. You need to check:
IF the roof pitch is the same AND the height of the roof above the point where the trusses sit on the wall is the same, yes. You'll have to look carefully and measure scale drawings or measure the actual trusses...

The dimension described here is generally referred to as the "heal" of the truss by truss manufacturers.

Like Thumper states, tell the truss mfg what you are looking for and they can make sure the heal dimension is the same for the scissor truss and the storage truss regardless of what lumber is used for the bottom chords.

GD

 

[Milton Shaw]

One thing to consider is to use 19 5/8 spacing of the trusses to give you an extra margin of strength if you are in a snow area. That's one more truss in 8 feet than on 24" spacing. I used it on my floor trusses for my second floor great room over my shop. Makes for a stronger floor with less movement under load. Couple of bucks now might prevent either a bowed roof underlayment or worse problems from snow load.

 

[nehog]

One thing to consider is to use 19 5/8 spacing of the trusses to give ...

That odd spacing may make it harder to stagger the sheathing... If you go 16" you can stagger half sheets easily, with all seams on a truss member. Otherwise you are going to be relying on things like H clips which are not very strong.

 

[readhead]

I thought every body quit using 19 5/8" 20 years ago. That was a flash from the past.

 

[DekeT]

Sorry, what I meant was by mixing different sized base cords will my top rafters still come out even for putting on roof as long as pitch is the same?

If they are designed that way, yes. If not, no. Whomever you purchase the trusses from will design them nearly any possible way you want them.

 

[jaybird3897]

Thanks for the replies everyone, I will check with my truss builders on this one.

 

[garagebuilder]

It also depends on whether the overhangs are top chord or bottom chord.

If they are top chord overhangs and the top chord is the same dimensional lumber then it will work because the heel depth ill be the same.

Bottom chord overhangs will create an issue but it can be addressed by adding enough additional top plate framing to the top of the wall where the trusses with the smaller heal sits.

 

[Travis28715]

I personally would stick with 16" O/C in any case. IMHO

 

[NUTTSGT]

Just tell the truss manufacture what you are looking for, they will set them up to do what you want.

Yep, it shouldn't be a problem for them.