Methods & Data
Where each number comes from
BuildSMART is built on top of the ESTCP reference implementation at AbbyHodson/buildsmart_abby, which estimates baseline material demand and state-level supply and demand for cement, aggregate and supplementary cementitious materials. Anything the tool shows that the reference implementation does not compute is listed here, so that no figure in the interface has to be taken on trust.
Backed by the reference implementation
Same equation or same dataset, same units. These carry no badge in the tool: an unmarked number is one you can trace.
- Baseline material demand. Material intensity per square foot times gross floor area, with reuse credit capped at new demand, exactly as the reference implementation computes it. est_base_demand.py
- National material flows. 2023 United States cement and concrete material flow accounts, shown for scale only. US cement concrete MFA 2023.csv
- Net availability. Supply minus demand, the reference implementation's own availability metric. est_default_availability.py
- Reuse credit. The same five reuse-eligible materials as the reference implementation, each credited only up to the new demand for that material. est_base_demand.py
- State supply and demand. Supply and demand tonnages read from the same Olsson supplementary dataset the reference implementation reads, with its coverage gaps preserved rather than filled in. est_default_availability.py
Derived from reference-backed inputsDERIVED
The inputs trace upstream, but the transformation applied to them is BuildSMART's own and is documented on this page.
- Availability tier. A BuildSMART classification of the real supply-to-demand ratio at chosen thresholds; the reference implementation reports the raw difference and defines no tiers. est_default_availability.py
- Concrete mix constituents. Regional NRMCA mix coefficients from the reference data, renormalised so the constituents sum to the concrete mass; the reference multiplies them directly instead. est_base_demand.py
- Project material flows. Baseline demand routed through source and product columns using national import shares; the split between columns is a presentation choice, not a measurement. US cement concrete MFA 2023.csv
Awaiting dataAWAITING DATA
The calculation is in place and correct, but the measurement it needs does not exist upstream yet, so nothing is shown rather than something estimated.
- Near-NBVC aggregate reserves. Permitted reserves near Naval Base Ventura County exist in the dataset as fifty-year totals, not as the annual supply series the scenario would need. availability_data.xlsx
- Steel availability. The reference implementation marks steel supply and demand as forthcoming, so no state-level steel availability can be shown. est_default_availability.py
- Supply outside California. The reference implementation has cement plant capacity and permitted aggregate reserves for California only, so every other state is reported as unknown rather than estimated. est_default_availability.py
Not implemented yetNOT IMPLEMENTED YET
Presented in the interface but backed by no computation.
- Installation coordinates. Installation latitudes and longitudes were compiled for BuildSMART without a cited source or stated accuracy, and only set the map pin and the concrete mix region.
Made-up numbers, shown only on requestMOCK DATA
The reference implementation contains no cost, scenario or substitution model, so the figures on these surfaces were typed in by hand to give the interface something to draw. They are not estimates and not projections. They stay hidden until you turn on MOCK DATA, and everything they produce is badged.
- Alternative materials. These substitution effects are made up. The reference implementation has no substitution model, so the replacement caps and the cement clamp were picked by hand and are not sourced from any study.
- Material cost. These prices are made up. The reference implementation has no cost model, so the unit prices were typed in by hand for BuildSMART and are not quotes, estimates or calibrated figures.
- Supply chain vulnerability. Reads real availability tiers, but its cost figures and its mitigation advice rest on the made-up cost and substitution numbers, so it is withheld with the rest of the mock data.
- Supply scenarios. These scenario effects are made up. The reference implementation has no scenario model, so every multiplier was picked by hand and none is calibrated against any observed disruption.
Material Demand Estimation
BuildSMART estimates baseline material demand using material intensity coefficients (MIC) derived from detailed building archetypes. The baseline calculation sums material quantities across all specified new buildings:
demand[material] = Σ MIC[archetype][material] × sqftReused material from demolished buildings is calculated similarly and capped at the corresponding new demand. The calculation follows the exact methodology in the reference implementation (ESTCP repository, est_base_demand.py).
Concrete Constituent Normalization
Concrete materials (Portland cement, fly ash, slag, aggregates, water) are derived from regional concrete mix designs (NRMCA LCA v3.1). The app normalizes to a physically consistent basis:
cement = concreteLbs / (1 + Σ coef)
constituent[c] = concreteLbs × coef[c] / (1 + Σ coef)This ensures the sum of constituents equals the total concrete mass and accurately reflects regional production practices. Cementitious content for availability checks also includes cement from CMU (12% by mass) and Type S mortar (15% by mass).
Material Availability Tiers
Availability is classified by coverage ratio (supply / demand at state level):
| Tier | Coverage Threshold | Interpretation |
|---|---|---|
| Abundant | ≥ 1.2 | Supply exceeds demand; low risk |
| Tight | 0.95 - 1.19 | Supply near demand; moderate risk |
| Constrained | < 0.95 | Supply < 95% of demand; high risk |
| Unknown | null | Insufficient data |
The threshold of 0.95 (95% coverage) reflects the literature standard adopted by the research team for supply-chain criticality assessment.
Aggregate Supply Near Naval Base Ventura County
The "Near NBVC" regional scarcity scenario uses permitted aggregate reserves from the Pacific Southwest and Central Valley regions (Ventura, Los Angeles, Santa Barbara, and Kern counties). The California Geological Survey reports 578 MMT of permitted reserves in these pilot regions against a 50-year demand projection of 2,249 MMT in the same area. This 26% coverage ratio identifies a critical bottleneck for construction material sourcing near the installation. When the scarcity scenario is activated and the project is located within the pilot region, aggregate supply is constrained to these regional reserves rather than statewide availability.
Concrete Cost Pricing from Constituents
The cost of Cast-in-place concrete in the cost panel is calculated from its constituent materials (Portland cement, fly ash, slag, aggregates, water) using the concrete mix design proportions for the project's region and their respective unit costs:
concreteCost = Σ_c (constituent[c].lbs × unitCost[c])This approach ensures that concrete cost reflects current material markets and regional supply conditions. When alternative materials (fly ash, pozzolans, recycled powder) are substituted for Portland cement, their respective unit costs replace the cement cost, reflecting actual market pricing for secondary materials.
Scenario Parameters
Scenarios apply multiplicative factors to supply and demand to simulate supply-chain stressors:
Simulates 50% disruption to imported material supply. Cement demand is increased by the national import share (×0.5); domestic cement supply remains available. Affects gypsum and steel as informational flags only (v1 limitation: no state supply data available).
In-state sourcing only (no interstate substitution). Cement supply is reduced by 18% (nameplate → operational capacity factor). Aggregate supply uses the "Near NBVC" regional permitted reserves when the project is in California and within the pilot region (Ventura, Los Angeles, Santa Barbara, or Kern counties); else statewide baseline reserves. v1 note: nearNBVC supply bounds in availability.json pending integration; logic is in place for future data updates. Natural pozzolans bound shifts to "slow" (California only).
Reused material credit is halved (50% reduction). Recovered fly ash is halved and bound drops to "low". Recycled concrete aggregate utilization is halved. Concrete waste recovery is not credited.
Fly ash and slag supply bounds shift to "high"; slag supply is reduced 10% (fuel switching stress). Recovered fly ash is unchanged. Reflects reduced coal-fired power generation.
Substitution Caps & Assumptions
| Material | Replaces | Cap |
|---|---|---|
| Recovered fly ash | Portland cement | 30% |
| Natural pozzolans | Portland cement | 40% (CA only) |
| Recycled concrete powder | Portland cement | 30% |
| Recovered gypsum | Gypsum board / stucco | 100% |
| Recycled concrete aggregates | Virgin aggregates | 100% |
The combined cement replacement (fly ash + pozzolans + RC powder) is clamped to 50% maximum. Recycled concrete aggregates are noted as "currently used mainly as road base; structural use conditional" per industry practice.
Unit Costs (2025 USD / Short Ton)
The following table lists provisional 2025 unit costs for all materials and constituents:
| Material | USD/ton | Source | Provisional |
|---|---|---|---|
| Cast-in-place concrete Typical ready-mix concrete | $175 | Engineering estimate | ✓ |
| Carbon steel (rebar) | $850 | USGS Mineral Commodity Summaries 2025 | ✓ |
| Plywood | $950 | Engineering estimate | ✓ |
| Cold-formed, galvanized steel | $1100 | Engineering estimate | ✓ |
| Hot-rolled, structural steel | $1050 | Engineering estimate | ✓ |
| Cold-formed, structural steel | $1050 | Engineering estimate | ✓ |
| Concrete masonry unit | $275 | Engineering estimate | ✓ |
| Solid modular brick | $400 | Engineering estimate | ✓ |
| Type S mortar | $95 | Engineering estimate | ✓ |
| Oriented strand board | $800 | Engineering estimate | ✓ |
| Softwood | $750 | Engineering estimate | ✓ |
| Stucco | $120 | Engineering estimate | ✓ |
| Polyisocyanurate foam board | $1200 | Engineering estimate | ✓ |
| Expanded polystyrene foam | $800 | Engineering estimate | ✓ |
| Glass mat gypsum board | $120 | USGS estimate for gypsum | ✓ |
| Aluminum | $2800 | USGS Mineral Commodity Summaries 2025 | ✓ |
| Aluminum, 20% recycled content | $2600 | Engineering estimate | ✓ |
| #15 felt | $250 | Engineering estimate | ✓ |
| #30 felt | $300 | Engineering estimate | ✓ |
| Transite | $500 | Engineering estimate | ✓ |
| Thermoplastic olefin | $1200 | Engineering estimate | ✓ |
| Laminated glass | $1800 | Engineering estimate | ✓ |
| Polyvinyl butyral interlayer film | $3500 | Engineering estimate | ✓ |
| Asphalt built-up roof membrane | $200 | Engineering estimate | ✓ |
| Granulated modified bitumen cap sheet | $250 | Engineering estimate | ✓ |
| Asphalt shingles | $250 | Engineering estimate | ✓ |
| Wood cladding (softwood) | $1000 | Engineering estimate | ✓ |
| Clay tiles | $800 | Engineering estimate | ✓ |
| Modified bitumen membrane | $225 | Engineering estimate | ✓ |
| Portland cement | $160 | USGS Mineral Commodity Summaries 2025 | ✓ |
| Fly ash | $45 | Engineering estimate (byproduct value) | ✓ |
| Blast furnace slag | $35 | Engineering estimate (byproduct value) | ✓ |
| Mixing water | $5 | Engineering estimate | ✓ |
| Crushed coarse aggregates | $16 | USGS Mineral Commodity Summaries 2025 (crushed stone) | ✓ |
| Natural coarse aggregates | $14 | USGS Mineral Commodity Summaries 2025 (sand & gravel) | ✓ |
| Crushed fine aggregates | $16 | USGS Mineral Commodity Summaries 2025 | ✓ |
| Natural fine aggregates | $12 | USGS Mineral Commodity Summaries 2025 (sand & gravel) | ✓ |
| Recovered fly ash | $25 | Engineering estimate (recovered byproduct) | ✓ |
| Natural pozzolans | $55 | Engineering estimate | ✓ |
| Recycled concrete powder | $35 | Engineering estimate | ✓ |
| Recycled concrete aggregates Currently used mainly as road base | $20 | Engineering estimate | ✓ |
| Recovered gypsum | $50 | Engineering estimate | ✓ |
All costs marked "provisional" pending validation with RSMeans and regional supplier surveys. Sources: USGS Mineral Commodity Summaries 2025, engineering estimates.
Data Files & Attribution
Version & Citation
BuildSMART v1 (September 2026). For details on methodology and to cite this tool, consult the ESTCP final report and supplementary documentation available from Lawrence Berkeley National Laboratory. Questions? See the contact page.