This is part 2 about building lightweight, insulated vaults with earthbags. Lower courses are gravel-filled bags to prevent water wicking up in the wall. Above that are standard earthbags filled with subsoil. These bags could be stabilized with lime or cement if there’s risk of flooding. Upper bags are filled with insulation and tied to rebar or bamboo arches.
The main difference between this design and the previous one for dry climates is the steep roof. Here, I’m showing a thatched roof because I’m working with a group who’s interested in building this way. Metal roofing would be a good choice for capturing roofwater and for areas where thatch isn’t available or practical. Both roofing methods protect the plastered vault from direct exposure to the elements and save on plaster work. Without a roof, the vault would be much more susceptible to roof leaks. A roof also helps prevent overheating in hot climates and mold in tropical climates.
We know earthbag domes and roundhouses are extremely popular. I predict earthbag vaults will rapidly gain in popularity as the word spreads of their speed and ease of construction. I’m almost certain they would be easier and faster to build than earthbag domes. Expect to see more on this topic in the near future.