| system | initial cost ($ + hrs) / sqft | annualized cost ($ + hrs) / sqft | other resources | revenue | benefits | | ------------------------------- | --------------------------- | -------------------------- | -------------------- | ------- | ---------------------------------------------- | | earthen floor earthbag building | $18.15 + 1.1 hrs | $.80 + .048 hrs | locally-sourced soil | n/a | sustainable, cost-effective building envelopes | #### Assumptions - labor source: provided by unskilled but trained community members. - local resources: soil is locally sourced, minimizing transport costs. - simple design: no plumbing, electricity, or high-end finishes included. #### Ongoing Labor .024 hrs/sqft | task | hours/sqft/year | notes | | ------------------- | --------------- | ------------------------------ | | inspections | 0.006 | annual structural checks | | repairs | 0.012 | minor replacements and fixes | | surface maintenance | 0.006 | reapplying finishes, cleaning | | total | 0.024 | annual maintenance activities | #### Operating Costs $0.80/sqft | component | annual cost ($/sqft) | justification | | ------------------- | -------------------- | --------------------------------------- | | inspections | $0.20 | annual checks for structural integrity | | repairs | $0.40 | minor material replacements or fixes | | surface maintenance | $0.20 | reapplying finishes, cleaning | | total annual cost | $0.80 | comprehensive maintenance costs | #### Initial Costs Breakdown $18.15 + 1.1 hrs / sqft -> $0.4030 + 0.024 hrs / sqft | **Component** | **Initial Cost ($ + hrs) / sqft** | **Lifespan (Years)** | **Amortized Cost/Year ($ + hrs) / sqft** | **Justification** | | ---------------------- | ------------------------------- | -------------------- | -------------------------------------- | ------------------------------------------------------------------------------------ | | **Earthen Floor** | $4.82 + 0.2 hrs | 50 | $0.0964 + 0.004 hrs | Gravel base, foam insulation, vapor barrier, linseed oil, etc. | | **Exterior Walls** | $8.33 + 0.5 hrs | 50 | $0.1666 + 0.010 hrs | Polypropylene bags, soil/clay, stabilizer, barbed wire, plaster, structural supports | | **Roofing** | $3.00 + 0.15 hrs | 30 | $0.1000 + 0.005 hrs | Basic corrugated metal roof | | **Trusses/Structural** | $2.00 + 0.25 hrs | 50 | $0.0400 + 0.005 hrs | Roof trusses and structural framing | | **Total Initial Cost** | $18.15 + 1.1 hrs | - | $0.4030 + 0.024 hrs | Comprehensive envelope costs (walls, floor, roof, structural) | [Rest of material costs remain unchanged as they were reasonable] #### Cost Breakdown ##### Earthen Floor $4.82 / sqft | **Item** | **Cost** | **Notes** | | ------------------------- | ----------------- | ------------------------------------------- | | Gravel for base | $1,350 | 15 cubic yards @ $90/yd delivered | | Rigid foam insulation | $520 | 10 sheets (4x8, 2" thickness) @ $52/sheet | | Vapor barrier | $500 | 2,000 sq ft with overlap @ $0.25/sq ft | | Sand | $1,000 | 20 tons @ $50/ton delivered | | Clay | $0 (local source) | Delivery costs, typically minimal for local | | Straw | $500 | 100 bales @ $5/bale | | Linseed oil & sealers | $450 | 10 gallons @ $45/gallon plus hardeners | | Waterproofing (wet areas) | $0 (variable) | Natural hydraulic lime, tadelakt materials | | **Total Cost / 1000 sqft** | **$4,820** | Includes all materials | ##### Exterior Walls $8.33 / sqft | **Item** | **Standardized Cost** | **Notes** | | ------------------------ | --------------------- | ------------------------------- | | Polypropylene bags | $3,000 | 6,000 bags @ $0.50/bag | | Soil/clay | $500 | Local source plus delivery | | Stabilizer (lime/cement) | $300 | Minimal stabilizer for strength | | Barbed wire | $100 | For coursing between bags | | Natural plaster | $600 | Lime plaster, natural sealers | | Structural supports | $833 | For openings, bond beams | | **Total / 1000 sqft** | **$8,333** | Includes all materials | #### Key Benefits - sustainability: uses natural and locally sourced materials, reducing environmental impact. - cost-effectiveness: low material and labor costs compared to conventional building methods. - customizability: adaptable to various climates and aesthetic preferences. - durability: earthbags are resistant to fire, pests, and extreme weather conditions.