Decorative glass block adds light to bathrooms while maintaining privacy. It’s easy to set glass block in earthbag walls and other thick walls made of strawbale, cob, stone, adobe, etc. Here’s how I added glass blocks to our Earthbag Roundhouse Studio.
I made two separate 2×6 bucks just a little larger than the glass blocks for each opening. There are two bucks and two blocks per window — one on the inside and one on the outside with a gap in the center of the wall. Make the bucks with short scraps of wood if possible. Figure out how much curvature you want on the plastered edges and then put the bucks in place as you lay the bags. (Ours are 1”- 2″ from the edge of the bags.) The earthbags on each side hold the bucks firmly in place. The bucks are strong enough to support earthbags on top with no lintel, although you could add boards to create an attractive lintel. When you’re ready to set the glass blocks, add some small finish nails inside the bucks as stops so they don’t slide in too far. The plaster curves around, covers the bucks and seals the gaps. Mask off the glass to reduce cleanup later.
Video of finished Roundhouse Studio
(We’ve since replaced the thatch with 30-year red microconcrete roofing tiles.)