Which is stronger, a cavity block wall or double block solid wall?

[epsilonGreedy]

I am thinking ahead to horizontal forces on a wall at wall-plate level introduced by cut roof rafters (assuming minimal joists).

 

My first thought was the cavity wall would be stronger because it is 50% wider but then I realized that wall ties are effective under tension but only marginally so under compression.

 

 

[Jeremy Harris]

31 minutes ago, epsilonGreedy said:

I am thinking ahead to horizontal forces on a wall at wall-plate level introduced by cut roof rafters (assuming minimal joists).

 

My first thought was the cavity wall would be stronger because it is 50% wider but then I realized that wall ties are effective under tension but only marginally so under compression.

 

 

 

 

There should be near-zero lateral force from the rafters to the walls.  The two main options are either to hang the rafters from the ridge beam, so the ends just rest on the walls, with the loads being taken by the ridge beam, or to use a ridge board with the lower ends of the rafters tied together with joists to prevent the spreading load being imposed on the top of the walls.

 

 

[bassanclan]

The wall plate will be sitting on the inside leaf (usually) exerting little or no force on the outer leaf of the cavity, but as @JSHarris impies, you don't need to worry about lateral forces

[Oz07]

yeh if theres lateral forces you've got a problem

loads go down not across