Preliminary estimating is for the stage when drawings are incomplete — a site plan, a floor plate, a program area, or a massing model. You need a budget number that is defensible, not a bid. We build the estimate from gross floor area (SF), floor-plate SF per level, exterior wall LF, and system-level allowances, then summarize by CSI MasterFormat division so the number maps to how you will buy the work later. This is conceptual cost estimating, not a bid: quantities come from square footage and assemblies estimating rather than piece-by-piece counts. If your drawings are further along, budget estimating or a full construction estimating package may fit better.
- Deliverable
- Excel estimate + marked-up PDF plans
- Organized by
- CSI MasterFormat section
- Turnaround
- 24–48 hours for most projects
- Pricing
- ZIP-code-adjusted material and labor pricing
- Software
- Bluebeam Revu, PlanSwift, RSMeans data
We work in Bluebeam Revu, PlanSwift, and RSMeans data with ZIP-code-adjusted material and labor pricing. Where a model exists, we can pull quantities from Revit or AutoCAD exports, or work from a BIM file for a 5D-style rollup. Deliverables are Excel and PDF, organized by division, with marked-up plan sets. Most projects return in 24–48 hours; rush is available. From a schematic set we can produce a material takeoff at the system level and a labor cost estimate by trade, or an elemental estimate if your pro forma is organized by building element rather than CSI division.
Use this service to set a GMP target, compare structural systems, test a site yield, or validate a lender budget before you commit design fees. The estimate logs every assumption — bay size, wall type, finish level, MEP system — so the next iteration can be measured against it. When the design matures, the same model converts to a bid estimate or hard bid support.
What a preliminary cost estimate includes
At concept, scope is defined by systems and allowances, not by detail. We measure what is shown, apply unit rates to what is not, and list every assumption on a separate sheet. The estimate is organized by CSI MasterFormat division so you can compare it to a future bid or GMP without re-sorting.
Area-Based Budget
Gross building area by floor and occupancy, priced with ZIP-adjusted RSMeans allowances for shell and core.
SF · SF/floorEnvelope Takeoff
Exterior wall LF by assembly type, glazing SF by size class, and roof SF by membrane system.
LF · SFStructural System
Concrete CY or steel TON by bay count and typical bay size, with foundation and slab-on-grade quantities.
CY · TON · EAInterior Partitions
Partition LF by type — stud, CMU, demountable — plus door EA by type and window EA by size class.
LF · EAFinishes Allowance
Floor SF by material, ceiling SF by system, and paint SF, each carried as a system-level allowance.
SFMEP Allowance
Plumbing fixture EA by type, HVAC tonnage or SF-per-ton by zone, and electrical service amps with device EA.
EA · TON · AMPSSite & Utilities
Clearing SF, paving SF, and utility LF by pipe type, with fire protection sprinkler head EA or SF coverage.
SF · LF · EAGeneral Conditions
Duration in months, supervision LS, temporary facilities, and permits carried as separate line items.
MONTHS · LSWhat every preliminary & conceptual estimating takeoff includes
- Gross building area (SF) by floor and occupancy type
- Exterior envelope: wall LF, glazing SF, roof SF
- Structural system: concrete CY or steel TON by bay count
- Interior partitions: LF by type (stud, CMU, demountable)
- Finishes: floor SF by material, ceiling SF, paint SF
- Openings: door EA by type, window EA by size class
- Plumbing fixture count EA by fixture type
- HVAC tonnage or SF-per-ton allowance by zone
- Electrical: service amps, device EA, lighting SF
- Site: clearing SF, paving SF, utility LF
- Fire protection: sprinkler head EA or SF coverage
- General conditions: duration in months, supervision LS
How we take off incomplete drawings
- Establish the basis of estimateWe record drawing date, sheet list, scale, and what is shown versus assumed. If the set is a massing model and a program, we set the gross SF and floor-to-floor height from the model and confirm against the program. This basis sheet travels with the estimate so anyone can see what was measured and what was allowed. It also logs the drawing revision and any addenda issued to date.
- Measure the primary systemsWe take off slab SF by level, exterior wall LF by type, roof SF, and bay count from the structural grid. For steel, we apply a typical TON per bay or SF-per-ton rate from RSMeans data, adjusted for bay size and height. For concrete, we calculate CY from thickness × area and add footing and column volumes separately. Rebar is carried as a separate line at a typical pounds-per-CY factor.
- Build the MEP allowancesPlumbing is counted by fixture EA from the plan; HVAC is sized by tonnage or SF-per-ton by zone; electrical is set by service amps and device EA or SF-per-device. We do not guess pipe LF at concept — we carry a system allowance and note the basis. The allowance is tagged so it can be replaced with a measured [quantity takeoff](/quantity-takeoff-services/) when drawings mature. Fire protection is carried as head EA or SF coverage.
- Apply ZIP-adjusted pricingMaterial and labor rates are adjusted to the project ZIP code using RSMeans data. We separate labor, material, and equipment so you can see the effect of a union versus open-shop assumption. Rates are dated; escalation to the midpoint of construction is a separate line, not buried in the unit rate. Sales tax and local fees are applied as separate line items.
- Log assumptions and contingenciesEvery undefined item gets a line: design contingency, construction contingency, escalation, and allowances for specialties. The assumption log lists what is included, what is excluded, and what would change the number. This is the sheet your lender or owner's rep will read first. It also records the source for each allowance, such as a geotech report or utility provider.
- Summarize by CSI divisionThe estimate rolls up to CSI MasterFormat divisions 01–33 at a summary level, with detail by system. Early emphasis falls on Divisions 03, 05, 08, 09, 22, 23, and 26 because those drive the budget. The summary is formatted so it can be compared directly to a future bid or GMP. Each division total is traceable to the takeoff sheets and assumption log.
What we need from you
- DrawingsAny set you have: site plan, floor plans, elevations, sections, or a massing model. PDF or DWG. Note the date and revision.
- ProgramGross SF by use, floor count, and occupancy type. If you have a room count or unit mix, send it.
- Site infoGeotech report if available, survey, utility plan, and any known constraints such as easements or floodplain.
- System preferencesStructural system, exterior wall type, MEP system, and finish level. If undecided, we can compare alternates.
- ScheduleStart date, duration, and phasing. This drives escalation and general conditions.
- LocationProject ZIP code or city. We adjust material and labor pricing by ZIP.
- BasisIs this for a pro forma, a GMP target, a lender, or a design comparison? The answer sets the contingency level.
Sample conceptual takeoff format
The sample below shows how a conceptual takeoff is organized: CSI section, line item, quantity, unit, and the sheet or source the quantity came from. Quantities are illustrative.
| Section | Line item | Qty | Unit | Ref. |
|---|---|---|---|---|
| 03 30 00 | Slab on grade, 5 in thick, 4,000 psi | 18,400 | SF | S-101 |
| 03 30 00 | Mat foundation, 36 in thick, 4,000 psi | 4,200 | SF | S-102 |
| 03 30 00 | Column, 24 × 24 in, 12 ft tall | 24 | EA | S-201 |
| 03 30 00 | Elevated slab, 8 in thick, 4,000 psi | 12,600 | SF | S-103 |
| 03 30 00 | Continuous footing, 24 × 12 in | 412 | LF | S-104 |
| 05 12 00 | Structural steel, bay frame, 30 × 30 ft | 186 | TON | S-201 |
| 08 11 00 | Hollow metal door, 3 × 7 ft, pair | 24 | EA | A-101 |
| 09 51 00 | Acoustical ceiling, 2 × 2 ft lay-in | 12,600 | SF | A-102 |
| 22 40 00 | Water closet, floor-mounted, commercial | 18 | EA | P-101 |
| 23 31 00 | HVAC allowance, 1 ton per 400 SF | 46 | TON | M-101 |
| 26 51 00 | Lighting allowance, 1.2 W per SF | 22,080 | SF | E-101 |
Units of measure in conceptual estimating
At concept, we measure in units that survive design changes: gross SF, wall LF, system EA, and lump-sum allowances. Each unit is tied to a drawing location or program input so the number can be traced.
| Item | Unit | How it's measured |
|---|---|---|
| Gross building area | SF | Measured to outside face of exterior wall, by floor and occupancy |
| Floor plate | SF | Per level, from grid-to-grid dimensions or program area |
| Exterior wall | LF | Perimeter at each typical floor, by wall type |
| Concrete | CY | Volume from thickness × area, plus footing and column takeoff |
| Structural steel | TON | Weight from bay count and typical member sizes, or SF-per-ton allowance |
| Roofing | SF | Plan area plus slope and overhang allowance |
| Piping | LF | By system (domestic, sanitary, storm) from fixture count and riser diagram |
| Electrical devices | EA | By type from floor plan device count or SF-per-device allowance |
| Allowances | LS | Lump sum for undefined scope, logged with basis and date |
Worked example: conceptual takeoff of a structural steel bay frame
This walkthrough shows how we build a conceptual steel quantity from a massing plan. The dimensions and quantities below are illustrative and are not taken from a real project. The goal is to show the sequence and the math, not to give you a number to copy.
Given (illustrative):
- Building footprint: 120 ft × 90 ft = 10,800 SF per floor
- Floors: 4, so gross building area = 43,200 SF
- Bay size: 30 ft × 30 ft on a typical grid
- Floor-to-floor height: 13 ft
- Typical steel weight allowance: 8 lb/SF (from RSMeans data for a 30 × 30 bay frame at this height)
Step 1 — Count bays.
- Bays along length: 120 ft ÷ 30 ft = 4
- Bays along width: 90 ft ÷ 30 ft = 3
- Bays per floor: 4 × 3 = 12
- Total bays: 12 × 4 floors = 48
Step 2 — Estimate steel tonnage from SF.
- 43,200 SF × 8 lb/SF = 345,600 lb
- 345,600 lb ÷ 2,000 lb/ton = 172.8 tons
Step 3 — Cross-check by bay.
- 172.8 tons ÷ 48 bays = 3.6 tons per bay
- A 30 × 30 bay at 13 ft with typical beams and columns commonly falls between 3 and 4 tons. The cross-check is reasonable, so we keep 172.8 tons.
Step 4 — Add waste and miscellaneous steel as separate lines.
- Waste factor: typical range is 2–5% for structural steel. Use 3%: 172.8 × 0.03 = 5.18 tons
- Miscellaneous steel (embed plates, angles, lintels): allow 1.5% of total: 172.8 × 0.015 = 2.59 tons
- Total steel line: 172.8 + 5.18 + 2.59 = 180.57 tons
Step 5 — Apply ZIP-adjusted pricing.
- We pull material and labor rates for the project ZIP from RSMeans data and separate them. Labor for steel erection is affected by union status, prevailing wage, and local crew availability. We log the basis.
Step 6 — Compare alternates.
- We run the same footprint as a cast-in-place concrete frame at 24 × 24 ft bays. Concrete volume is calculated from slab thickness × area plus column and footing volumes. The two systems are compared on cost per SF of floor area, schedule impact, and bay-size flexibility. The difference is logged on the summary sheet.
Step 7 — Log assumptions.
- Bay size, floor-to-floor height, steel weight allowance, waste factor, and pricing date all go on the assumption log. If the bay size changes to 40 × 40 ft, the tonnage is re-run, not adjusted by a percentage.
What moves a preliminary construction cost estimate
Relative impact on a typical estimate for this trade, based on estimator judgment. Select a bar for details.
Structural system
Cast-in-place concrete, steel frame, load-bearing masonry, and mass timber price differently per SF of floor area and carry different bay-size flexibility. A 30 × 30 ft bay steel frame and a 24 × 24 ft concrete frame can differ by more than 15% in the structure package. We compare alternates at the same gross SF.
Cast-in-place concrete, steel frame, load-bearing masonry, and mass timber price differently per SF of floor area and carry different bay-size flexibility. A 30 × 30 ft bay steel frame and a 24 × 24 ft concrete frame can differ by more than 15% in the structure package. We compare alternates at the same gross SF.
Wall type drives both cost and schedule: curtain wall, storefront, CMU with brick veneer, EIFS, and metal panel have different LF rates and different glazing ratios. At concept, we measure wall LF by type and apply a rate per SF of wall area, not per SF of floor.
HVAC tonnage or SF-per-ton, service amps, and fixture count are the three MEP inputs that move the budget most. A change from a packaged rooftop system to a chilled-water plant can shift Division 23 by double digits. We log the basis so it can be re-priced.
Escalation is applied to the midpoint of construction, not today's date. A 24-month schedule with a 12-month midpoint carries more escalation than a 12-month schedule. We state the rate and the midpoint date on the summary sheet.
Design contingency and construction contingency are separate lines. At schematic design, design contingency is typically higher; it drops as drawings mature. We log both so you can see the total budget versus the base estimate.
Paving SF, clearing SF, utility LF, and stormwater requirements vary by site. Permit and impact fees are jurisdiction-specific — confirm the adopted code edition and fee schedule with the local building department. We carry them as a separate owner line.
Union versus open-shop labor, prevailing wage requirements, and local crew availability affect the labor component. We adjust labor rates by ZIP code and note the basis. A project in a tight labor market may carry a premium for overtime or per diem.
Common scope gaps in conceptual cost estimating
Conceptual estimates miss items for one reason: they are not on the drawings yet. These are the gaps we see most often and how we catch them.
- Escalation is applied to today's date instead of the midpoint of construction. We catch it by tying escalation to the schedule start and duration, and stating the midpoint date on the summary.
- Design contingency and construction contingency are combined into one line. We separate them so you can see how much is for undefined design versus field conditions.
- Permit fees and impact fees are estimated from a previous project in another jurisdiction. We list them as a separate owner line and tell you to confirm the fee schedule with the local building department.
- Utility connection and tap fees are omitted because the civil drawings are not complete. We carry an allowance and note the utility provider as the source to verify.
- Temporary facilities, winter conditions, and phasing costs are buried in general conditions. We break them out by duration in months so you can see the cost of a longer schedule.
- Hazardous material abatement and unforeseen site conditions are not carried at all. We add a line item allowance and note that a survey is required before pricing.
- Elevator and conveying systems are often left off concept estimates because they are not on the floor plan. We count EA by type and stops from the program or a typical core layout.
- Fire protection is omitted when the sprinkler drawings are not available. We carry a head count or SF coverage allowance based on occupancy and construction type.
- Landscape and irrigation are excluded because they are a separate package. We add a Division 32 allowance and note that it may be bid separately.
Structural system alternatives at concept
At concept, the structural system is the largest single cost driver you can still change. We compare alternates on cost per SF of floor area, schedule impact, and bay-size flexibility.
| System | Typical bay range | Cost per SF driver | Schedule impact |
|---|---|---|---|
| Cast-in-place concrete | 20–30 ft | Formwork SF, rebar lb/CY, concrete CY | Longer cure times; post-tensioning can speed decks |
| Structural steel frame | 30–40 ft | Steel TON, connections EA, fireproofing SF | Fabrication lead time; fast erection once on site |
| Load-bearing masonry | 15–25 ft | CMU SF, grout CY, reinforcement LF | Weather-dependent; slower in winter |
| Mass timber | 20–30 ft | Glulam LF, CLT SF, connection EA | Fabrication lead time; dry site conditions preferred |
| Concrete podium with wood frame above | Varies | Podium CY plus wood framing LF and joist SF | Two trades sequenced; transfer slab coordination |
Codes and standards that affect a conceptual estimate
Model codes
At concept, the model code family sets the parameters that drive quantities. The IBC and IRC establish occupancy, construction type, allowable height and area, and fire separation, which in turn set the structural system, fire-resistance ratings, and sprinkler requirements. The IECC affects envelope R-values and glazing ratios, which change wall and roof quantities. The NEC sets service size and device counts. The IPC or UPC sets fixture counts. NFPA 13 sets sprinkler head counts. Confirm the adopted edition with the local building department before you price.
Industry standards
ACI 318 governs concrete strength and reinforcement, which drives rebar pounds per CY and mix design. ASTM A992 and A36 define structural steel grades, which affect tonnage and connection design. SMACNA standards cover duct construction, which changes sheet metal SF and gauge. GA-600 covers gypsum board systems, which drives wall and ceiling SF. NRCA guidelines cover roofing assemblies, which affect roof SF and insulation. These standards tell you what the system includes, not just its size.
Specification sections
An estimator must read the specification sections that carry cost. Division 03 30 00 tells you concrete strength and finish, which changes mix and labor. Division 05 12 00 tells you steel grade and connection type, which affects tonnage and fabrication. Division 08 11 00 tells you door material and hardware, which changes EA pricing. Division 09 51 00 tells you ceiling type and grid, which affects SF and waste. Division 22 40 00 tells you fixture type and trim, which changes EA pricing. Division 23 31 00 tells you duct material and insulation, which affects SF and gauge. Division 26 51 00 tells you lighting type and controls, which changes device EA and circuiting.
Local amendments
Adopted code editions and amendments vary by state, county, and city. A jurisdiction may be on an older IBC edition, may have amended snow, wind, or seismic loads, or may require stricter energy or green building provisions. Impact fees, permit fees, and utility tap fees are set locally and change the owner's soft costs. We carry these as separate owner lines and tell you to confirm the adopted edition and fee schedule with the local building department. For projects in Texas, California, Florida, New York, or North Carolina, we note the state-level amendments we see most often.
Who uses a preliminary estimate for contractors
Developers and owners
You need a budget before you commit land or design fees. The conceptual estimate gives you a cost per SF and a total that can be tested against pro forma rents or sales. The assumption log tells you what has to be true for the number to hold.
Architects
You need to keep the design within the owner's budget. An elemental or CSI-organized conceptual estimate lets you see which systems are driving cost and where a design change will move the number. It also gives you a basis for value engineering discussions.
General contractors
You are asked for a budget before drawings are complete. A conceptual estimate from a third party gives you a defensible number and a documented basis. It also pre-loads the takeoff structure so the hard bid later is faster.
Owner's representatives
You are validating a GMP or a lender budget. The estimate review shows what is included, what is excluded, and what contingencies are carried. You can compare it to the contractor's number line by line.
Subcontractors
You are tracking a project early to plan crew and fabrication capacity. A system-level conceptual estimate tells you the approximate scope size in your trade, so you can decide whether to pursue the bid.