Capping the cob wall with a bond beam

We are transitioning from the cob masonry to the carpentry of the roof. It’s an exciting time as we wrap up the cob and hope to get a roof on in the next few weeks to dry everything in and lock in our hard work of the last year. This transition requires a specialized continuous section of concrete masonry units placed on top of the cob wall that will form a stable platform for the wood-framed roof to rest on. Earth walls tend to have poor lateral stability over the centuries, and a concrete bond beam will effectively take the structural lateral pressure off the cob and transfer it to where cob’s strengths are - it’s compressive load-bearing capacity. The U-shaped CMUs are reinforced with two layers of #4 rebar which are tied into the vertical rebar coming through the cob walls into the bottom of the bond beam, and then this assembly is filled with a continuous pour of concrete, with J bolts added to tie in the top plate and transition to the framing of the roof.