Straw bales have an insulation value of R35-R50, depending on the bale size and the direction that they are stacked.
We started by finding the nails in the existing sheetrock with a magnet and removed the nails. Then we removed the sheetrock from the walls. We used a drywall jack to remove the sheetrock from the ceiling. (We reused the sheetrock by nailing manageable sized sections to the rafters.) We drilled small holes in the ring beam along the exterior facing walls to vent air behind the bales. Then we meshed the holes and stapled 1/4” metal mesh on the studs and joists to keep mice out of the bales. We screwed wood bucks around the windows and meshed the bucks and pinned the edges of the mesh to the bales with landscape pins.
Our lime plaster mix: 1 part water, 1 part hydrated lime, 3 parts sand, 1-2 handfuls of chopped straw. We chopped straw with a streamer in a clean bin.
We plastered the back sides of the bales and stacked the bales against the mesh—this helped the bales to stick to the mesh and protects the bales. We stacked the bales in a brick format and anchored the bales to the studs using landscape pins in the bales with wire screwed to the studs. After filling the gaps between the bales with loose straw, we trimmed the bales using a streamer to level the surface before plastering. We plastered a full coat over the bales and let it dry before filling areas to level the surface. Our full final coat did not include chopped straw. We circulated air in the room and allowed a week to dry.
Mesh and window buck
Bales in brick format and dry wall jack
Final coat of plaster