Light Straw Clay Workshop

Yesterday we held our first workshop, which was all about infilling the inner 2x4 stud walls with Light Straw Clay (LSC).

 The wall is prepped: outside forms (half-inch plywood sheathing) are screwed on to the outside of the studs, electrical boxes are installed and screwed in flush with the wall, and the 1x2 strips are nailed to the studs.

 Closeup of the 1x2s which key into the LSC, effectively locking it into the wall.

Packing in the straw, which has been coated with a thick mixture of clay and water.  It's staged in the plywood bin in the foreground. 

The first two stud bays have been almost fully packed behind the forms.  Starting from the bottom and working up, it's a little tricky to completely fill the wall: how do you pack in the space behind the last form? 

 Answer: we do the last little bit from the outside to make sure the inner face of the LSC is as smooth and regular as possible.  That will make applying the clay plaster that much easier.  Note the outer 2x6 wall with diagonal bracing located within the inner cavity.

We pack sideways to engage the 1x2 strips, and fill in the last little bit in the middle of the cavity with very wet, clayey straw by hand.  Then we take off the small side forms and place a full length form to try to flatten out the hand-stuffed batches as much as possible.

 Closeup of the hand-stuffed areas.

Final LCS wall from the inside.  That looks NICE!  Note the blocking in the top of the wall to facilitate hanging the kitchen cabinets.