This is the actual workflow for running a custom home bid through BuildCrux multi-pass AI. The pipeline is built for plan-set takeoff on 30 to 60 sheet architectural sets — architectural, structural, MEP, finish schedule, specifications. The output is a phase-grouped, allowance-itemized estimate ready for sub solicitation and senior review, typically 70 to 90 line items on a mid-luxury 4,000 to 6,000 sqft custom home. Total bidder time end-to-end: about 16 hours spread across 5 to 7 calendar days. Manual takeoff alone is 16 to 24 hours; the AI pipeline compresses the bid prep window without compromising accuracy.
BuildCrux multi-pass is a three-pass pipeline: Pass 1 identifies sheets by discipline, Pass 2 runs takeoff with computed areas using the compute_area tool, Pass 3 applies unit costs using lookup_unit_cost and groups output by construction phase with allowances broken out as separate line items. The pipeline handles 30 to 60 sheet architectural sets natively; larger sets (60+ sheets) split per-page using pdf-lib. This page documents the full workflow step-by-step including the senior review checkpoints and the sub solicitation parallel work.
Step 1 — Confirm bid type with customer
Confirm contract structure (fixed-price with allowances, cost-plus fixed fee, cost-plus percentage, or hybrid) before takeoff. The contract structure determines the markup approach and the customer-facing proposal format. Most retail custom home bids are fixed-price with allowances; the bid output structure assumes this default but is editable for cost-plus structures.
Step 2 — Pre-bid lot walk
A 60 to 90 minute lot walk before plan-set upload catches site conditions that drive site work cost and contingency rate. Lot slope, soil visible signs, tree count in footprint, utility tie-in distance, existing structures, neighbor proximity, driveway access, drainage, HOA notes. Pre-bid lot walk is not optional on custom home bids — site work cost can vary by $35K to $150K between flat and sloped lots and contingency rate has to reflect lot risk.
Step 3 — Upload the architectural set
Drag the architect plan PDF into the BuildCrux estimate creation form. Custom home architectural sets are typically 30 to 60 sheets across five disciplines: architectural (18 to 30 sheets), structural (4 to 8), MEP (8 to 12), finish schedule (2 to 4), specifications book (2 to 6 if separate). Most architect-supplied sets are 25 to 80 MB. Multi-volume sets (architectural + specifications book + lighting designer book) can be uploaded as separate files; the pipeline cross-references between them via Pass 1 sheet identification.
Step 4 — Pass 1 sheet identification
Pass 1 reads the cover sheet and sheet index, identifies each sheet by discipline (A-series architectural, S-series structural, P-series plumbing, E-series electrical, M-series HVAC, F-series finish schedule), and tags non-drawing sheets (specifications text, energy compliance forms, structural calculations) so they are excluded from takeoff but referenced for spec language. Pass 1 runs in 90 to 180 seconds and is included in the preflight (no credit charged).
The pipeline displays the sheet inventory on the preflight confirmation screen. Sanity-check before approving Pass 2 + Pass 3. Common review catches on custom home sets: a "details" sheet that mixes architectural and structural details (re-tag based on dominant content), a "schedule" sheet that is actually a window schedule rather than a finish schedule (re-tag as architectural schedule), or a specifications book uploaded as a separate file with its own sheet index (link to architectural set).
Step 5 — Pass 2 takeoff with compute_area
Pass 2 runs takeoff with the compute_area tool plus extract_text plus count_symbols. The tool extracts main-floor area, basement or crawl area if present, garage area, covered porch/patio area, framing lumber bd-ft, sheathing sf, roofing area, window and exterior door counts, interior door counts, plumbing fixture counts, electrical fixture counts, HVAC equipment sizing, insulation sf by location, drywall sf, interior trim lf, flooring sf by category, cabinetry lf by room, countertops sf by location, appliances count, landscape sf, and exterior hardscape sf. Output is a structured takeoff table grouped by construction phase.
Pass 2 takeoff items by source sheet and extraction tool.
| Pass 2 takeoff item | Source sheets | Tool used |
|---|---|---|
| Main-floor + basement + garage area | Floor plans | compute_area |
| Framing lumber bd-ft + sheathing sf | Framing plans + structural details | compute_area + extract_table |
| Roofing area + perimeter | Roof plan + elevations | compute_area + compute_perimeter |
| Window + door counts + sizes | Schedule + elevations | count_symbols + extract_table |
| Plumbing fixture count + type | Plumbing plan + fixture schedule | count_symbols + extract_table |
| Electrical fixture count + type | Electrical plan + lighting schedule | count_symbols + extract_table |
| HVAC equipment + ductwork | Mechanical plan + equipment schedule | extract_table + compute_area |
| Insulation sf by location + R-value | Wall sections + spec book | compute_area + extract_text |
| Drywall sf | Floor plans + ceiling plans | compute_area |
| Interior trim lf (crown + base + casing) | Finish schedule + floor plans | compute_perimeter |
| Flooring sf by category | Finish schedule + floor plans | compute_area + extract_text |
| Cabinetry lf by room | Cabinetry layout + finish schedule | compute_perimeter + extract_table |
| Countertops sf | Cabinetry layout | compute_area |
| Appliance count + type | Appliance schedule | extract_table |
| Landscape + exterior hardscape | Site plan + landscape sheets | compute_area |
Step 6 — Pass 3 unit costs with allowance breakouts
Pass 3 applies unit costs from the lookup_unit_cost catalog (editable per workspace), groups output by construction phase, and breaks allowances out as separate line items with reconciliation rule annotation. Pass 3 also produces long-lead annotations for items with lead times over 6 weeks (custom millwork, specialty windows, designer fixtures, imported tile, custom interior doors).
- Phase grouping: site work + foundation, framing, roofing, exterior, MEP, drywall, interior trim, paint, cabinetry, flooring, fixtures, appliances, landscape, exterior hardscape, builder overhead
- Allowance breakouts: cabinetry, countertops, plumbing fixtures, lighting fixtures, flooring, appliances, exterior finishes, smart-home, window treatments (excluded), landscape
- Long-lead annotations: items with lead times >6 weeks flagged in the output
- Inspection milestone tags: each phase tagged with required inspection (foundation, framing, MEP rough, insulation, drywall, final)
- Customer-facing vs internal split: cabinetry shows allowance dollar amount externally and includes builder install labor breakout internally
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Get StartedStep 7 — Senior review + sub solicitation
Senior estimator review of AI output runs 45 to 75 minutes on a 38-sheet mid-luxury bid; longer on 50+ sheet high-luxury. Concurrent with senior review, sub solicitation runs in parallel across 14 to 24 subs (foundation, framing, roofing, plumbing, electrical, HVAC, insulation, drywall, cabinetry, tile, flooring, paint, landscape, hardscape). Sub solicitation runs 6 to 12 hours of bidder time spread across the 10-day bid window.
- Sheet inventory sanity check from Pass 1 output (re-tag any mis-classified sheets)
- Line item completeness check (add missing items the AI did not surface; typically 4 to 8 per bid)
- Unit cost overrides for builder-specific sub network (5 to 12 line items typically need adjustment)
- Allowance range customization for the specific customer (1 to 3 categories)
- Contingency rate adjustment for lot conditions (always; default 3 to 7 percent)
- Long-lead annotation refinement (1 to 4 items; refine to your current supplier-specific lead times)
- Phase budget sanity check against historical % of total per phase
- Inspection milestone tagging confirmed per phase
- Sub solicitation packets sent in parallel (during the 45 to 75 minute senior review)
Step 8 — Allowance pricing + proposal + submission
Final step: price allowances against designer-supplied schedule or against market-median for customer-self-selecting, apply markup layers (general conditions 3 to 6 percent, builder overhead 10 to 16 percent, contingency 3 to 7 percent, builder profit 8 to 14 percent), generate proposal PDF with scope-of-work writeup plus allowance breakdown plus reconciliation rules plus 9-draw schedule, and submit via builder portal or email. BuildCrux generates the proposal PDF automatically from the line-itemed estimate plus configurable template; builder adds custom customer-facing language and submits.
| Workflow step | Time | Bidder vs AI |
|---|---|---|
| Confirm bid type with customer | 30 to 60 min conversation | Bidder |
| Pre-bid lot walk + drive | 2 hr 20 min | Bidder |
| Plan upload + metadata setup | 5 to 10 min | Bidder |
| Pass 1 sheet identification | 90 to 180 sec | AI |
| Preflight review + Pass 2/3 approve | 5 min | Bidder |
| Pass 2 takeoff | 6 to 12 min | AI |
| Pass 3 unit costs + phase grouping | 4 to 8 min | AI |
| Senior estimator review | 45 to 75 min | Bidder |
| Sub solicitation (parallel work) | 6 to 12 hr spread over 10 days | Bidder |
| Allowance pricing | 2 to 4 hr | Bidder |
| Proposal writeup + draw schedule build | 3 to 5 hr | Bidder + AI assist |
| Submission to customer | 30 min | Bidder |
| Total wall-clock | 5 to 7 days | Hybrid |
| Total bidder hours active | 14 to 22 hr | Bidder |
Frequently asked questions
How big a plan set can the pipeline handle?+
Up to 500 MB per file via the Files API. Most custom home plan sets are 25 to 80 MB. Multi-volume sets (architectural + specifications book + lighting designer book) can be uploaded as separate files and cross-referenced. Sets over 500 MB (rare on residential) are split per-page using pdf-lib.
How does the pipeline handle architectural sheets versus structural sheets?+
Pass 1 identifies sheets by discipline from the sheet index. Pass 2 takeoff runs per-discipline: architectural sheets give areas and floor plans; structural sheets give framing lumber, beam specs, foundation rebar; MEP sheets give fixture counts and equipment sizing; finish schedule gives allowance category quantities. Pass 3 unit costs apply per-discipline rates and group output by construction phase (which spans multiple disciplines per phase).
Can I run cost-plus contracts through the pipeline?+
Yes. The takeoff output is the same; only the markup structure differs. For cost-plus fixed-fee, replace the markup percentages with the agreed fixed fee. For cost-plus percentage, replace the profit percentage with the agreed cost-plus percentage. The customer-facing proposal output adjusts to show "estimated total" rather than "bid total" with cost breakdown attached.
How does the AI handle finish schedule allowance breakouts?+
Pass 1 identifies the finish schedule sheet (F-series or named "finish schedule"). Pass 2 extracts the allowance categories from the schedule (cabinetry, countertops, plumbing fixtures, lighting, flooring, appliances, etc.). Pass 3 surfaces each allowance as a separate line item with default budget range based on tier and reconciliation rule annotation. The senior review adjusts allowance budget per customer-specific selections.
What is the credit cost for a custom home estimate?+
For entry-custom to mid-luxury on 30 to 45 sheet plan sets: 1 standard credit. For high-luxury on 45 to 60+ sheet sets with multi-volume specifications: 1 commercial credit (15-credit equivalent from the same pool). Pricing is presented in the mode-confirmation modal before the run starts.
How does the pipeline handle CO additions during construction?+
COs run through a simplified version of the same pipeline. Upload the CO scope (revised drawing or a paragraph description), Pass 2 takeoff against the changed scope, Pass 3 unit costs using the same catalog. Output is a CO line item with markup at the same percentage as the baseline contract. CO is created in BuildCrux as an attached document to the parent project; customer e-signs the CO before scope work begins.
The bottom line
AI multi-pass workflow for custom home estimating is a structured pipeline: bid type confirmation plus lot walk plus plan upload plus three AI passes plus senior review plus sub solicitation plus allowance pricing plus proposal plus submission. Total elapsed time 5 to 7 days; bidder hours 14 to 22 active. The unlock is not "AI replaces the estimator" — it is "estimator does 2 to 3 custom home bids in the time they used to do one, and the bids land inside the same 2 to 4 percent accuracy band as 20-hour manual takeoff." For a small custom home builder doing 4 to 8 builds per year, that scales bid volume without scaling headcount.
See the workflow applied to a real $1.4M custom home
See how AI compares to manual takeoff and PlanSwift
See the residential remodel AI workflow
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