| name | preliminary-cost-estimate-report |
| description | Use this skill when a quantity surveyor, cost manager, owner's representative, or project estimator needs to produce a preliminary (Class D / Schematic Design level) construction cost estimate for a new building, renovation, or civil works project. Covers elemental cost breakdown, location and contingency factors, exclusions and assumptions log, and a cost manager review block.
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Preliminary Cost Estimate Report
Converts project brief information into a DRAFT Class D (Schematic Design / Order-of-Magnitude) construction cost estimate report with an elemental cost breakdown, location and market-condition adjustments, tiered contingencies, and a clearly documented assumptions and exclusions list. Produces a report for the cost manager or QS to verify before presenting to the owner or design team.
Flow
Phase 1 — Project Intake
Ask one question at a time. Wait for each answer before proceeding.
- Project identification: project name, client/owner name, location (city and country/region), and intended use date for the estimate.
- Project type: select the primary category:
- New construction vs. renovation/addition (state percentage of existing building affected if renovation)
- Building type: office, retail, residential multi-family, residential single-family, industrial/warehouse, healthcare, education, hospitality, mixed-use, civil/infrastructure, other (specify)
- Gross floor area: total GFA in m² or ft² (specify unit). For multi-building projects, list each building separately.
- Construction type: structural system (wood frame / light gauge steel / structural steel / cast-in-place concrete / precast concrete / masonry / other) and number of above-grade and below-grade storeys.
- Occupancy and code basis: intended occupancy classification and applicable building code jurisdiction (e.g., IBC 2024, NBCC 2020, AS 1170, Eurocode).
- Scope inclusions: which of the following are in scope? (Confirm each) — site preparation and earthworks, foundations, structural frame, exterior envelope, roofing, interior fitout, mechanical (HVAC), electrical, plumbing, fire protection, elevators, site services (utilities), landscaping and site works, demolition.
- Scope exclusions and owner-supplied items: list items the client will supply directly or are excluded from the GC's scope (e.g., FF&E, owner-procured equipment, telecom, security, art).
- Project quality level: economy / standard / mid-range / high-end / premium (affects unit-rate selection).
- Available reference data: has the user provided a design brief, area schedule, concept drawings, or comparable project costs? If yes, ask the user to share them now.
Confirm the scope summary with the user before proceeding.
Phase 2 — Location and Market Adjustment
Apply location cost indices to base rates:
- Identify the cost index region for the project location (use Rider Levett Bucknall, Turner & Townsend, or RSMeans regional indices as the reference framework — state the reference used).
- Apply a location multiplier relative to the base index city (e.g., 1.00 = national average; note that actual index values must be verified by the cost manager).
- Note the current market-conditions factor: hot market (escalation > 5% p.a.) / stable / soft. Flag if the estimate is being used more than 6 months from the estimate date — cost escalation should be reapplied.
Phase 3 — Elemental Cost Build-Up
Produce a table of cost elements. For each element, state: Element | Description of Scope Included | Unit Rate ($/m² GFA or $/ft² GFA) | Quantity | Total Cost | Notes/Assumptions.
Standard elements (include all; mark N/A if confirmed out of scope):
| # | Element |
|---|
| 1 | Demolition and site preparation |
| 2 | Substructure (excavation and foundations) |
| 3 | Superstructure (frame and upper floors) |
| 4 | Roof construction |
| 5 | External walls and cladding |
| 6 | Windows, doors, and glazing |
| 7 | Internal partitions and doors |
| 8 | Floor finishes |
| 9 | Ceiling finishes |
| 10 | Wall finishes |
| 11 | Fittings, fixtures, and equipment (built-in only) |
| 12 | Plumbing and sanitary |
| 13 | HVAC and mechanical ventilation |
| 14 | Electrical and lighting |
| 15 | Fire protection (sprinkler and detection) |
| 16 | Vertical transportation (elevators, escalators) |
| 17 | Hydraulics and specialty piping |
| 18 | Communications and security rough-in |
| 19 | External works and landscaping |
| 20 | Site services and utilities connections |
After each element, note the assumed unit rate source: comparable project data / published cost guide / regional benchmark / cost manager adjustment.
Phase 4 — Contingency and Risk Loading
Apply three tiers of contingency:
| Tier | Purpose | Typical Range | Applied Rate |
|---|
| Design contingency | Incomplete design definition at schematic stage | 15–25% of construction cost | State applied % |
| Construction contingency | Unforeseen conditions and minor scope changes | 5–10% of construction cost | State applied % |
| Escalation contingency | Cost movement between estimate date and tender/award | Depends on program | State applied % and basis period |
State the reasoning for each applied rate. If the user has provided a project schedule, compute escalation to the midpoint of construction.
Phase 5 — Cost Summary and Report Assembly
Produce the DRAFT report:
DRAFT — FOR COST MANAGER REVIEW
PRELIMINARY COST ESTIMATE REPORT
Project: [PROJECT NAME]
Client: [CLIENT NAME]
Location: [CITY, COUNTRY]
Building Type: [TYPE]
GFA: [X] m² / ft²
Estimate Class: Class D — Schematic Design / Order of Magnitude
Estimate Date: [DATE]
Prepared by: [NAME / FIRM — to be completed by cost manager]
Status: DRAFT — Not for owner distribution until cost manager review
─────────────────────────────────────────────────────────────────────────
ELEMENTAL COST PLAN
─────────────────────────────────────────────────────────────────────────
[Elements table: # | Element | $/m² GFA | Quantity (m²) | Total ($) | Notes]
SUBTOTAL — CONSTRUCTION COST (ELEMENTS 1–20): $XXX,XXX
─────────────────────────────────────────────────────────────────────────
CONTINGENCIES
Design Contingency [X]% $XXX,XXX
Construction Contingency [X]% $XXX,XXX
Escalation Contingency [X]% $XXX,XXX
TOTAL CONSTRUCTION COST (INCL. CONTINGENCY): $XXX,XXX
─────────────────────────────────────────────────────────────────────────
PROJECT COST ADDITIONS (excluded from GC contract — for reference only)
Professional fees (design + QS) [%] $XXX,XXX
Authority fees and permits $XXX,XXX (allow)
FF&E and owner-supplied items [Stated scope exclusion]
Land (if applicable) [Not included]
TOTAL PROJECT COST (ORDER OF MAGNITUDE): $XXX,XXX
─────────────────────────────────────────────────────────────────────────
COST RATE SUMMARY
Construction cost / m² GFA: $X,XXX / m²
Construction cost / ft² GFA: $XXX / ft²
─────────────────────────────────────────────────────────────────────────
ASSUMPTIONS AND EXCLUSIONS LOG
[Numbered list]
INFORMATION GAPS AND OPEN ITEMS
[Numbered list — items that must be resolved before upgrading to Class C]
COST MANAGER REVIEW BLOCK
This report is a DRAFT Class D estimate. It must be reviewed and signed by
a qualified QS or cost manager before owner presentation or budget-setting.
Reviewer: ________________ Firm: ________________ Date: ________
Signature: ________________
Phase 6 — Quality Gate
Before outputting the report, confirm:
- Every element with a significant cost driver has a stated assumption
- The estimate class (Class D) and DRAFT status are clearly labelled
- No element is marked "TBC" without a placeholder value and a corresponding open item
- The cost manager review block is present and unsigned
Key Rules
- Never present this estimate as a final tender price, guaranteed maximum price, or construction contract sum.
- Always state the estimate class and date prominently — Class D estimates become stale after 6 months without escalation reapplication.
- If the user provides comparable project data, incorporate it and note the source; do not invent unit rates from training knowledge alone.
- Ask one question at a time during intake. Do not front-load all questions.
- Flag any element where insufficient information prevents a reliable estimate — do not silently set it to zero.
- Never include contingency figures as a substitute for proper scope definition.
Output Format
Single markdown document structured per the Phase 5 template. Use tables for the elemental cost plan, contingency build-up, and cost summary. Flag all open items and information gaps in a numbered list at the end before the review block.
Feedback
If this skill did not meet your needs or you encountered a gap, please open an issue at https://github.com/archlab-space/Open-Skill-Hub/issues. Surface this link only when the user expresses an unmet need or dissatisfaction — never in normal interactions.
