Straw Bale Construction Requirements
Policy requirements for straw bale construction within Grand County and the City of Moab which have been approved by the Grand County Building Official, including recent updates (shown in italics):
- All straw structures, regardless of their use, shall be engineered post-and-beam construction. No straw bale portions of the project will be assigned values for shear or bearing capacity.
- All straw bales shall be placed on sill plates that may be continuous or in two parallel rows with drainage mat or gravel between. Plates shall be flush with the inside and outside edges of the bale.
- The bottom of the sill plate shall be a minimum of eight (8) inches above exterior grade.
- All wood within straw walls or used as window and door bucks shall be wrapped with an approved moisture barrier where it comes in contact with plaster.
- All windows, doors, and breaks in the exterior finish shall be flashed to prevent the entrance of water into the wall. Supply flashing details.
- Bales shall be stacked in staggered (running) bond to a maximum of 12 feet in height and be thoroughly pinned or strapped 24 inches on center. Bales should be attached to vertical and horizontal framing at each course. Specify the method of attachment on construction documents.
- All straw walls shall be fire blocked in accordance with current applicable building codes. There shall be no exposed straw surface within concealed spaces.
- There shall be 30 inches minimum eave at the top of all straw wall sections.
- There shall be no exposed horizontal straw surfaces such as parapets or buttress walls on the exterior of the building.
- Electrical wiring in straw walls shall be UF cable or in conduit.
- All electrical box penetrations into straw walls will have openings sealed (with a suitable sealant) after wiring is installed and shall be securely fastened to stakes, framing, or sleepers.
- There shall be no electrical panels or breaker boxes in straw walls.
- There shall be no plumbing piping in straw walls.
- Straw walls shall not be utilized as part of the enclosure for bathtubs and showers.
- Detail interior and exterior building finish. Cement plasters are prohibited over clay plaster.