Does any alternative to a wood-framed wall beat it on cost, carbon or heat loss for a small house?

What it found

Prices six exterior wall systems (wood 2x6, steel stud, ICF, SIPs, CLT, 3D-printed concrete) on the 927 sq ft of net wall of the house-framing house, then runs 20,000 Monte Carlo draws over stylised cost, carbon and R-value ranges. Wood is cheapest in 96.8% of draws, lowest in product-stage carbon in 100% and lowest in first cost plus 30-year heat-loss cost in 99.9%; ICF and SIP save only about $500 of heat-loss present value against $5,500–8,300 more first cost, and SIP would need a 39% price cut to tie. SIPs and CLT take about half the crew hours. Stylised: every input is a range from memory, the result largely follows from them, biogenic carbon, avoided trades and strength are not credited or compared.

A figure from its own output

Paper, code and results

• README and method
• Experiments and results
• Code
• Tests

More in Open-source residential construction

• Does a small wood-frame house have enough shear wall for wind and earthquakes once the windows and doors are cut out?Does a small wood-frame house have enough shear wall for wind and earthquakes once the openings are cut out? At 115 mph and SDS 0.50 the 28 x 40 ft house uses 19% of a gable-wall line's capacity at 6 in nailing; the openings, not the load, are what shrink it. Stylised, capacities from memory.
• How much does accidental torsion add to the garage-front wall's demand in a rigid-diaphragm wind split?How much does accidental torsion add to the garage-front wall's demand in a rigid-diaphragm wind split? Offsetting the load up to 15% of the length in house-nailedwall's split raises a 22 ft-door wall from 0.36–0.59 to 0.44–0.71 demand over capacity, still under the flexible 1.05. Stylised.
• Does the rigid-diaphragm relief for a garage-front wall survive a nailed-wall stiffness model?Does the rigid-diaphragm relief for a garage-front wall survive a nailed-wall stiffness model? Four-term pier deflection (bending, shear, nail slip, hold-down) in house-diaphragm's rigid split: yes; a centred 22 ft door falls from 1.05 (flexible) to 0.36–0.59 demand over capacity. Stylised.
• Does the half-and-half load split understate the demand on a garage-front wall?Does the half-and-half load split understate the demand on a garage-front wall? In a toy stiffness model a rigid roof diaphragm gives the garage line less than half, so the flexible split governs; stylised, torsion not modelled.
• What does an open, reproducible plan set for a 480 sq ft backyard cottage look like when it is generated from code?What does an open plan set for a 480 sq ft backyard cottage look like when generated from code? A 24 x 20 ft ADU composed from the track's models: drawings, bill of materials, IFC, lateral check, envelope energy (a tight envelope cuts modelled heating and cooling cost 36-37%) and a cost index. A worked example, not a buildable design; every input assumed.
• At what climate does each envelope upgrade start to pay, when climate is a continuous axis?At what climate does each envelope upgrade start to pay? Climate as a continuous axis over house-energy's model: slab-edge R-10 from 3,271 heating degree-days with gas (2,386 with a heat pump), 3 ACH50 from 5,769, and cooling alone switches on only the attic and air sealing above ~3,000 cooling degree-days. Stylised: unsourced prices, no solar gain.

All 41 Open-source residential construction projects →

Other research topics

Proper scoring & elicitation28Effort & peer prediction9Verification games & slashing19Detection & tolerances14Markets as routers13Prediction-market design9Paying contributors8Decentralised training systems23Digital twins & sim-to-real164LLM chip design loops40Robot manufacturing loops53Ambient AI assistant46Self-replicating manufacturing34Simulation-first design64Engineered clothing45Task-specific AI accelerators40Algorithmic chip-design loops42Open-source purpose-built robots44The software-engineering loop43Adversarial human imitation41Open-source residential construction41Autonomous multi-angle capture34Sensing, imaging and 3D31Energy supply and dense energy storage39Robot societies among people31Agentic co-design of low-cost robots27Laundry-hanging robots25Machine learning on qualitative data23Robots on the building site27Civilizations & group psychology1History & human sciences1

Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.