Focus on labor hours, sequencing, coordination, and rework as dominant cost drivers. Shift attention from material swaps to buildability and repeatable execution, while avoiding durability regressions.
Builds on: A5 (size and design efficiency) · Leads to: A7 (alternative construction), A8 (energy performance) · Cross-series: P6 The Four Control Layers
P/A bridge: Which details should be simplified, standardized, or preapproved because ordinary crews cannot execute them reliably?
Building construction - labor (B07-BuildCost) - Most cost is labor plus the mistakes that force rework. Trade coordination, sequencing, and access prevent conflicts. A clean plan can save more than a product swap.
Risk: Complexity drives labor more than materials - small detailing choices multiply steps and errors.
AF: B07 - CRO-METHODS, CRO-STANDARDIZE
Building construction - materials (B07-BuildCost) - Material choices that simplify install can beat "cheaper materials." Durability-protecting minimums ensure cuts don't become callbacks.
Risk: Removing durability essentials (drainage/drying logic) creates long-term cost.
Framing vs HVAC routing conflict: Duct runs hit structural members; field modifications weaken structure or compress duct cross-section, increasing noise and reducing airflow.
Root: trades not coordinated at framing stage; HVAC layout not on structural drawings.
Window buck / air barrier confusion: Window installer and air-barrier installer each assume the other will seal the gap. Result: air leakage at every opening, comfort complaints, moisture risk.
Root: no single detail showing responsibility handoff at the opening.