May 28, 2012

More Bond Beam Prep

The west-side (Kiva) room has reached ceiling height and preparation work has begun to pour a bond beam. The photo below shows how I discovered that a sheet of inexpensive masonite board, could be cut in strips to act as a form for the eventual pouring of the concrete beam.


I like Masonite because it has a high strength-to-weight ratio and it's flexible.  And as one can see from the shapes of the rooms in this structure, I need that flexibility to accommodate these irregular shapes.  I hold the masonite in place securing 1"x2" pine strips into the cob with 4"-deck screws (see photo above that shows these vertical strips).   

I cut 12"-wide strips from the 4'x8' sheet of Masonite. Then I drew a line 5" down on each strip to denote the height of the bond beam channel.  The 7" of  board below the line is pressing up again the cob and utilized in holding the cob to the wall.

I'm amazed at how the "cob" wall can hold those screws tight.  I used this 'securing' method in a previous bond beam pour, the result of which can also be found in the top-left portion of the photo. I'm fairly confident I won't have any blowouts in the form when the bond beam is actually poured.  

I still need to install rebar in the channel prior to the pour.

The outer portion of the form is the rising cob wall.  Notice in the bottom photo a simple measurement  'fixture' I devised to ensure a 12-inches wide channel.  The fixture was moved around the back-face of the inner portion of the Masonite form as cob was applied to the top of this 24"-thick wall and up-against the fixture.

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