Construction of a 40-unit apartment complex with a 1,000 square-foot community building. Plus an additional 8 units in a future phase, bringing the total to 48 units. Site was developed with Glass Cullet (made from crushed bottles diverted from municipal waste) as a 100% substitute fill material to construct a slab-on-grade foundation capillary break, and for waterline pipe zone bedding. Approval of the alternative material required endorsement of geotechnical engineer and warrant by subcontractor of product quality, using manufacturer supplied 3rd-party product testing data. Glass cullet provided a low-cost, highly workable, permeable and structurally stable (equal or better) alternative material that is also clean and safe for workers and the environment.
This project was primarily challenging due to innovative insulation technique (straw bales); Tumwater and Thurston County jurisdictions were previously inexperienced with this type of engineering. Due to material choices based on ecologically based decision making, straw bale walls were approximately 2’ thick, this required extra discussion to verify footprint, whether to count sq ft from internal or external footprint of house—an important qualification to meet ADU permitting guidelines.