Commercial Sitework Estimating Guide

Start with the full plan set

Sitework scope is scattered across the whole set. Civil sheets carry grading, paving, and utilities, but the landscape sheets set topsoil and planter depths, the structural sheets set footing depths and pad requirements, the architectural site plan shows the trash enclosure and canopy footings, and the MEP site plans show dry utility routes and the grease interceptor. Bidding off the civil set alone is how scope gets missed.

Pull and log before takeoff:

Civil: cover, notes, demo, grading, paving, utility, detail, and SWPPP sheets, with the latest revision date on each.
Geotech: pad preparation, over-excavation, moisture and compaction, pavement sections, and the subgrade R-value or CBR.
Structural: foundation plan and footing schedule for pad depth and any over-excavation beyond the geotech.
Landscape: planter areas and depths that come off the grading, and the limits of irrigation sleeving.
Architectural: site plan for the enclosure, pads, bollards, and the drive-thru lane.
MEP site: gas, electric, and telecom routes, transformer pad, and service sizes at the building.
Specifications and the GC's bid instructions, including the scope sheet they want filled out.

Check the civil grading plan against the architectural finish floor. If they disagree, that is an RFI, and the answer changes your pad quantity.

Demo and strip

Demo on a commercial site is removal and disposal of whatever is in the way: asphalt, concrete, curb, buildings, slabs, fences, trees, and abandoned utilities. Quantify each by its own unit.

Asphalt removal by SF with thickness from cores or the demo note, hauled by the ton.
Concrete slabs and curb by SF and LF, with thickness and reinforcing noted; rebar and mesh change breaking production and the disposal fee.
Buildings by each with the hazardous materials survey in hand. If there is no survey, exclude abatement.
Trees by each and by size, stumps included.
Abandoned utilities: cap at the main, remove or abandon in place per the utility, and the potholing to find them.

Strip is separate. Topsoil, vegetation, and the top few inches of disturbed material come off before grading starts and either stockpile for reuse or haul off. The geotech sets the strip depth; if it does not, the site visit does. Strip volume is SF of disturbed area times depth divided by 27, and it is lost volume: it comes out of the cut side of the balance and does not go back as structural fill.

Rule of thumb: anything you cannot see on the demo plan but can see on the aerial is yours unless the scope letter says otherwise.

Grading to subgrade and pad certification

Grading quantities are computed to subgrade, not to finish grade. A commercial site has at least two different subgrades, and they are not at the same offset.

Building pad

Pad subgrade is finish floor minus slab, minus vapor barrier and sand, minus base under the slab, minus any over-excavation zone the geotech requires. The geotech typically calls for the pad to be over-excavated a stated depth below the footing bottom and a stated distance beyond the building line, then moisture conditioned and recompacted in lifts to a specified relative compaction. The geotech's technician tests it, and the certification letter is what the building inspector wants before footings are dug. Carry the over-excavation volume, the recompaction, the water, and the testing coordination. Pad certification is normally priced into the pad line.

Paving subgrade

Paving subgrade is finish asphalt grade minus asphalt minus base. The geotech usually requires scarifying and recompacting the top several inches of paving subgrade, a separate operation with its own water truck and roller time. Where the civil plan shows one pavement section and the geotech shows a thicker one, bid the plans and flag it.

The balance

Cut and fill are computed to those subgrade surfaces, with strip taken out of the top and pad over-excavation treated as its own operation. Apply shrink to the fill and swell to any export. Carry import or export as a unit price in the clarifications so the GC knows what a change costs.

Aggregate base under paving and curb

Type II aggregate base, or whatever the local spec calls dense graded crushed base, goes under asphalt, under concrete paving, under curb, and often under the building slab. Take each off by area and thickness, compute CY, then convert to tons.

Base CY = SF × thickness in feet ÷ 27
Base tons = CY × 1.85, our default conversion for compacted dense graded base. Confirm it against the supplier and the geotech unit weight for the local pit.

Rule of thumb: compute CY first and convert once. Shortcuts invite units errors.

Base under curb

Curb and gutter sits on base that the paving takeoff does not capture, because the curb line is outside the paving area or straddles it. House convention: base under curb = 4 ft wide × 0.5 ft deep × curb LF, in CY, then to tons at the same conversion. The 4-foot width covers the curb, gutter, and the compacted shoulder behind it.

Where base gets missed

Under sidewalk and ADA ramps when the detail shows a base layer.
Under dumpster pads, loading docks, and the drive-thru lane where the section is heavier.
Under the building slab, which is sometimes the concrete sub's scope and sometimes yours.
In utility trenches through paving, where the backfill spec requires base to subgrade.

State in the scope letter which of those you carry and which you do not.

Asphalt tons by section and lift

Asphalt is priced by the ton, and the ton count comes from area, thickness, and mix unit weight, by section and by lift.

Tons = SF × thickness in inches ÷ 12 × unit weight in pounds per CF ÷ 2,000
Rule of thumb: compacted dense graded hot mix runs roughly 145 to 150 pounds per CF. Use the supplier's mix design value when you have it.

Commercial sites usually have more than one section: standard parking, heavy duty drive aisles and truck courts, the drive-thru lane, and sometimes a thicker section at the dumpster approach. Take each area off separately. Multi-lift sections are priced per lift, because a 2-inch surface lift and a 3-inch base lift have different mixes and different paving production. Carry tack between lifts and on vertical faces.

Also carry:

Prime coat on base if the spec calls for it.
Seal coat and striping, including ADA symbols and signage, if the GC's scope sheet puts them on you.
Paving fabric or interlayer where shown.
Saw cut and tie-in to existing pavement at the street and at any phase line.
Minimum load charges and small quantity pricing from the plant for the drive-thru lane or a second mobilization.

Confirm whether the plant quote is picked up or delivered. On a small site the paving mobilization is a meaningful share of the line.

Curb and gutter, sidewalk and ADA

Flatwork on a commercial site is a long list of small items with their own units.

Curb and gutter by LF, split by type: vertical, rolled, ribbon, and the local standard detail numbers. Radius curb costs more than straight; count the radii.
Sidewalk by SF, by thickness, with reinforcing or fiber per the detail, and with the base or sand under it.
ADA ramps by each, with detectable warning surface by SF, and the running and cross slope tolerances that make them the most reworked item on the site.
Drive approaches, valley gutters, and spandrels by each or by SF per the local standard.
Dumpster pads, bollards, and the concrete at the drive-thru window and menu board by each.
Expansion and control joints, sealant, and the sidewalk under the canopy where the slab belongs to someone else.

The scope split with the concrete sub is the main risk. Read the GC's scope sheet, state what you carry in LF and SF, and list the items you exclude by name. A missed valley gutter or drive approach is a small dollar amount that turns into an argument.

Rule of thumb: curb quantities go wrong on both sides by missing the islands and the drive-thru lane. Trace every curb line on the plan once and total by type.

Site utilities and utility company splits

Site utilities on a commercial job run from the point of connection at the main to a stated distance from the building, and where that line sits is the first thing to pin down.

Wet utilities

Storm drain: pipe by size and LF, inlets and manholes by each, and the detention or retention system, which may be an underground chamber system with its own stone bed and fabric.
Sewer: lateral from the main, cleanouts, grease interceptor or sand-oil separator if the building type requires one, and the connection at the main.
Water: domestic service, meter and backflow, and the fire line with its own backflow and detector check. The fire line often ends a stated distance from the building, where the fire sprinkler contractor takes over.
Services: water and sewer stubs typically end 5 feet outside the building, and the plumber takes it from there. Say where your scope ends in feet.

Dry utility trench

Gas, electric, and telecom conduits are usually a joint trench, with the utility supplying conduit and cable and the sitework contractor digging, bedding, and backfilling to the utility's standard. Carry trench LF by depth and width, sand bedding, backfill, warning tape, and the transformer and switchgear pads if the GC puts them on you. Exclude conduit and wire unless quoted.

Utility company splits

Each utility has a point where its crews stop and yours start. Confirm the splits, the inspection requirements, and whether the utility's fees are in your bid or the owner's. Tap fees, meter fees, and utility company charges are almost always excluded and stated as such.

Dust control and SWPPP

Dust control and stormwater compliance are permit conditions with daily cost. Price them as work, not as a percentage.

Dust permit and the control plan the air district requires, with signage and the trained person on site.
Water truck hours for the duration of grading and for the period after grading before paving, plus a water meter or hydrant permit.
Soil stabilization or palliative on open pads that will sit, and on haul roads.
SWPPP: permit filings, the plan if one is not provided, BMP installation from the erosion control sheet, inspections at the required frequency, maintenance and replacement, and final removal.
Stabilized construction entrance and street sweeping on days trucks run.
Concrete washout and inlet protection through the curb and paving phases.

State in the proposal how many months of SWPPP maintenance and inspection the price carries. If the GC's schedule runs past that, the extension is a unit price per month. The same goes for water truck hours after your grading is done: if the pad sits open for the GC, that water is theirs.

GC bid forms, alternates and what GCs compare

The GC is comparing four or five sitework numbers side by side. The bid form, the scope sheet, and the scope letter are how they do it, and the sub that makes the comparison easy gets the follow-up call.

Bid forms and scope sheets

Fill out the GC's form completely, in their line items, in their order. If the scope sheet asks whether you include base under the building slab, answer yes or no; do not write see attached. Break the price into the lines they ask for, usually demo, earthwork, utilities, paving, and concrete.

Alternates and value engineering

Price listed alternates as separate lines with their own quantities. For value engineering, offer only ideas with a number attached: a thinner pavement section with the geotech's blessing, a different pipe material, or a balanced site by raising a pad.

What GCs compare

Base bid total and the breakdown by line.
Inclusions and exclusions against their scope sheet, line by line.
Unit prices for the likely changes: import and export per ton or CY, rock per CY, over-excavation per CY, additional base per ton, additional asphalt per ton.
Schedule assumptions: mobilizations included, working days, and phases.
Bond rate, insurance limits, and license class for the work.

Unit prices are not optional. A bid without them is the one the GC calls last.

Scope gaps, exclusions and the scope letter checklist

Disputes on commercial sitework come from the gap between what the GC assumed and what the sub carried. The common ones:

Base under the building slab and under sidewalk.
Over-excavation beyond the geotech's stated limits, and pad certification fees.
Import or export when the site does not balance.
Utility trench backfill in paved areas with imported material.
Service stubs and where they end relative to the building.
Dry utility trench, conduit, and pads.
Water truck hours after grading for other trades.
Surveying and staking: who provides control and who stakes.
Testing: who pays the geotech technician.
Permits and fees: dust, SWPPP, utility taps, street cut.

Scope letter checklist

Project name, GC, bid date, plan set and revision dates, addenda acknowledged, geotech report number.
Base bid total, with a breakdown by demo, earthwork, utilities, paving, and concrete.
Inclusions by line, with quantities for the big ones: cut and fill CY, base tons, asphalt tons, curb LF, pipe LF by size.
Exclusions by name, not by category.
Clarifications: subgrade conventions, balance assumption, pad certification, where utility scope ends, months of SWPPP and water carried.
Unit prices for the likely changes.
Alternates priced separately.
Mobilizations included and schedule assumptions.
Bond and insurance terms, payment terms, and the price validity period.
Signature block for the estimating department.

Rule of thumb: if an item took more than a minute to decide whether it was yours, it goes in the scope letter either way.

Common Questions

Is aggregate base quantified in tons or cubic yards?

Both, in that order. Compute CY from area and thickness first, then convert to tons at 1.85 tons per CY for compacted dense graded base, confirmed against the supplier and the geotech unit weight. Base is bought and delivered by the ton, so the ton figure is what goes on the bid.

What is the difference between building pad subgrade and paving subgrade?

Pad subgrade is finish floor minus slab, vapor barrier and sand, base, and the geotech over-excavation zone; it is recompacted and certified by the geotech. Paving subgrade is finish asphalt grade minus asphalt and base, usually scarified and recompacted in place. They sit at different offsets below finish grade and are graded as separate operations.

Where does the sitework contractor's utility scope end at the building?

Typically at a stated distance outside the building line, commonly 5 feet, where the plumber or fire sprinkler contractor picks up. The exact point varies by GC and by trade, so the scope letter should state it in feet for each service. Tap fees and utility company charges are normally excluded.

Should a sub bid to a GC include unit prices?

Yes. GCs compare unit prices for the likely changes, such as import and export, rock, over-excavation, additional base, and additional asphalt, alongside the base bid. A bid without them makes change orders harder to price and is less likely to get the follow-up call.

What belongs in a commercial sitework scope letter?

Project identification with plan dates and addenda, the base bid broken down by trade, inclusions with quantities, exclusions by name, clarifications on subgrade and balance assumptions, unit prices, alternates, mobilizations and schedule assumptions, and commercial terms. If an item took real thought to decide whether it was yours, it goes in the letter.

Who pays for pad certification?

The geotech's testing and the certification letter are usually paid by the owner through the GC's testing allowance, while the sitework contractor carries the over-excavation, moisture conditioning, recompaction, and coordination needed to pass. Confirm it on the GC's scope sheet and state it in the clarifications either way.

Commercial Sitework Estimating: Retail, Restaurants, Multifamily and Industrial