Most cob builders use a form to make their arches perfect. We, as you can see, did not. The windows are wonky. We like wonky. (Yeah, one pane is broken due to construction mishap.)
To make the arch over the windows and doors, we need to use super strong fiber straps made of sticky clay and straw. The arches distribute the weight of the wall evenly over the openings.
The Thermal Battery building has begun! That is, the cob and “urbanite” (repurposed chunks of sidewalk etc.) bench and bed the exhaust pipe is buried in. It will hold the heat and slowly release it back into the room.