Increase the strength of load-bearing structures

[LinusW]

If you want to increase the load-bearing capacity of a wall, is it better to reduce CC from 60 to 30 or double up the studs?

Instinctively, it seems like CC 30 must provide more strength than doubling the studs at CC 60. That was my plan from the start, but then a colleague said doubling the studs was best, and I became uncertain.

The timber is 28x70 if that matters.

 

[Tomture61]

28 x 70 is usually used as sparse paneling!
45 x 70 is commonly used in partition walls.
What is the wall supposed to support, a floor from above or?

 

[justusandersson]

What determines the load-bearing capacity of posts (i.e., standing studs) is the risk of so-called buckling (i.e., bending). Therefore, two screwed-together studs are stiffer in the weaker direction than the corresponding studs on closer c/c. In that respect, your colleague is correct. However, 28x70 is not a suitable dimension for a post.

 

[mattiasp]

What determines the load-bearing capacity of posts (i.e. standing studs) is the risk of so-called buckling (i.e. bending). Two screwed-together studs are therefore stiffer in the weak direction than corresponding studs on a tighter c/c. In that sense, your colleague is right. However, 28x70 is not a suitable dimension as a post.

Is it common to consider the buckling-preventing effect of the panels (gypsum/OSB/plyfa)?

 

[justusandersson]

Is the buckling-restraining effect of the boards (gypsum/OSB/plywood) usually taken into account?

Absolutely. The boards act both in the weak and the strong direction.

 

[LinusW]

Fully aware that the timber is too weak to support anything, hence this thread.
It will be used for a temporary shed that will (hopefully) stand for only 2-3 years.
They will not support a floor, just a simple roof for the shed.

28 x 70 is usually used as sparse paneling!
45 x 70 is usually used in partition walls.
What is the wall supposed to support, a floor from above or?

I wouldn't even dare to use 45*70 for a load-bearing interior wall.

We have a lot of spare paneling left over that needs to be removed anyway.