NASCLA Contractor cheat sheet

Delivery methods: design-bid-build awards to the lowest responsive bidder; design-build awards a single entity that holds both design and construction risk; CM at-risk holds a guaranteed maximum price.

The Notice to Proceed sets the contract start date from which contract time is measured; owner-caused work before NTP is generally not compensable delay.

Long-lead items (switchgear, elevators, structural steel, curtain wall) often carry 20+ week lead times and must be identified and released during preconstruction.

CSI MasterFormat Division 01 (General Requirements) governs submittals, temporary facilities, quality control, and closeout, not the technical scope of work.

Call 811 before any excavation; most states require 48 to 72 hours notice and utility marking before digging begins.

A geotechnical report establishes soil bearing capacity, groundwater elevation, and foundation type; bid assumptions should be tied to the specific borings provided.

Design contingency is commonly 5 to 10 percent at schematic design, tapering as documents complete; construction contingency is typically 2 to 5 percent of the contract sum.

Value engineering is a written proposal to reduce cost without reducing required function; it becomes binding only when accepted by the owner through a change order.

Constructability review compares drawings and specifications for conflicts, missing details, and infeasible sequencing before bid opening or before mobilization.

A bid bond is typically 5 to 10 percent of the bid amount and is forfeited if the low bidder fails to execute the contract and furnish performance and payment bonds.

Performance and payment bonds are each typically 100 percent of the contract sum; performance protects the owner, payment protects subcontractors and suppliers.

Addenda issued during bidding modify the bid documents and must be acknowledged in the proposal; failure to acknowledge can make the bid nonresponsive.

Labor burden (FICA, workers' compensation, unemployment, fringe) commonly adds 25 to 40 percent to base wage and must be applied before markup.

Conceptual or square-foot estimating carries roughly plus or minus 15 to 20 percent accuracy; a lump-sum bid built from a completed takeoff is closer to plus or minus 5 percent.

Unit price equals material plus labor plus equipment plus subcontractor cost plus overhead plus profit; quantity takeoffs add a waste factor by material type.

Balancing unit prices keeps the total bid unchanged while loading early or quantity-sensitive line items; owners may reject materially unbalanced bids.

A bid mistake (clerical error) must be reported to the owner promptly; withdrawal or correction after award generally requires showing a palpable mathematical error.

Negotiated procurement uses RFQ or RFP and evaluates qualifications and best value, not solely the lowest price.

A change order is signed by owner, contractor, and architect and fixes both price and time; a construction change directive orders the work before price and time are agreed.

An RFI is a written question about the documents; if the answer changes cost or time, it must be formalized as a change rather than left as an informal clarification.

Submittal review stamps are approved, approved as noted, revise and resubmit, and rejected; contractor review does not relieve the designer of design responsibility.

Retainage is commonly 5 to 10 percent of each progress payment, held until substantial completion and released in full at final completion after punch list closeout.

Substantial completion is the point at which the work is usable for its intended purpose; it starts warranty periods, releases most retainage, and shifts insurance and utility responsibility.

A conditional lien waiver takes effect only when the stated payment actually clears; an unconditional waiver is effective on signing.

Contract notice provisions are enforceable: late or missing written notice can waive an otherwise valid delay or extra-work claim.

Record documents (as-builts) must be kept current in the field and delivered at closeout along with warranties, O&M manuals, and attic stock.

Meeting minutes, daily reports, and photographs form the contemporaneous record used to support or defend claims.

The critical path is the longest dependent chain through the network and has zero total float; it sets the shortest possible project duration.

Total float = late start minus early start = late finish minus early finish; free float is the amount an activity can slip without delaying its successor.

Earned value: CV = EV - AC; SV = EV - PV; CPI = EV / AC; SPI = EV / PV; a CPI or SPI below 1.0 indicates overrun or delay.

Estimate at completion using the index method: EAC = BAC / CPI; remaining-work method: EAC = AC + (BAC - EV).

A time impact analysis inserts a fragnet of the changed work into the current accepted schedule to measure the delay to the completion date.

Delays are excusable (weather, owner, differing site conditions) or non-excusable (contractor means and methods); only compensable delays recover both time and money.

Concurrent delay generally entitles the contractor to a time extension but not to delay damages.

The schedule of values must be front-loaded only to the extent it tracks actual resource use; billing above earned value creates a liability for overbilling.

Acceleration is directed by the owner in writing and is compensable; constructive acceleration requires a documented excusable delay and a refused time extension.

Excavations 5 feet deep or more require a protective system (sloping, shoring, or shielding); a competent person must inspect daily and after rain or vibration.

OSHA sloping: Type A soil 3/4:1, Type B 1:1, Type C 1.5:1; spoil piles and equipment kept at least 2 feet from the edge, ladder within 25 feet of lateral travel.

Concrete slump is measured per ASTM C143 and the test completed within about 15 minutes of sampling.

Standard concrete test specimens are 4 by 8 inch or 6 by 12 inch cylinders; typically one set per 50 to 150 cubic yards per ACI and per specification.

Cold-weather concrete per ACI 306 keeps concrete at 50 degrees F or above during placement and protects it from freezing until it reaches 500 psi.

Field compaction is verified by nuclear density gauge and specified as a percentage (commonly 95 percent) of the maximum dry density from a Standard Proctor test.

Site logistics plans address laydown, temporary power and water, crane positions and swing radius, dumpster locations, and site access for emergency vehicles.

A Stormwater Pollution Prevention Plan and erosion controls (silt fence, inlet protection, stabilized entrance) must be in place before earthwork begins.

OSHA construction standards are 29 CFR 1926; general industry standards are 29 CFR 1910; recordkeeping is 29 CFR 1904.

The Focus Four hazards are falls, struck-by, caught-in or between, and electrical; they account for the majority of construction fatalities.

Fall protection is required at 6 feet in construction, 10 feet on scaffolds, and 15 feet during steel erection.

Supported scaffolds require guardrails at 10 feet, full planking, and a base-to-height ratio no greater than 4:1 unless designed otherwise.

Extension ladders need 3 feet of extension above the landing and a 4:1 slope; portable ladders are secured and extend above the access level.

Permit-required confined space entry requires atmospheric testing, an attendant, an entry permit, and rescue provisions under 29 CFR 1926 Subpart AA.

Employers must report a fatality within 8 hours and an in-patient hospitalization, amputation, or loss of an eye within 24 hours.

The OSHA 300 log is maintained during the year and the 300A summary is posted from February 1 through April 30.

Hazard Communication requires a written program, GHS-compliant labels, and accessible safety data sheets for every hazardous chemical on site.

Quality assurance is the owner's or designer's process of verifying the system; quality control is the contractor's inspection and testing of the work.

The USACE three-phase control system consists of a preparatory meeting, an initial inspection of the first work, and recurring follow-up inspections.

An inspection and test plan lists each inspection, the test method, the acceptance criteria, and whether it is a hold point or a witness point.

A hold point stops work until the inspector signs off in writing; a witness point requires notification but does not stop production.

Structural welds are visually inspected first, then examined by nondestructive testing (ultrasonic, radiographic, magnetic particle, or dye penetrant) per AWS D1.1.

A nonconformance report documents work that fails the acceptance criteria and tracks disposition: rework, repair, accept with concession, or reject.

Mock-ups and first-article installations establish the visual and performance standard before repetitive work starts.

Punch list items must be corrected before final payment; retainage is typically released when the punch list is closed and final documents are delivered.

Occupant load = floor area divided by the occupant load factor; common factors are 150 gross for business, 60 gross for mercantile, and 15 net for unconcentrated assembly.

IBC construction Types I through V are each divided into A (protected) and B (unprotected); Type I-A requires the highest fire resistance and Type V-B is unprotected wood frame.

Number of required exits rises with occupant load; occupancies with 1 to 49 occupants may generally have one exit, while 50 to 500 typically requires at least two.

IBC travel distance limits generally range from 200 to 400 feet depending on occupancy group and whether the building is sprinklered.

Fire-resistance-rated assemblies are identified by UL or GA design numbers, and penetrations must be firestopped to the tested system.

Drawing scale: at 1/4 inch equals 1 foot, one inch on the drawing represents 4 feet, so scaled dimensions are multiplied by 48.

Rebar callouts use eighths of an inch: a #4 bar is 1/2 inch diameter and a #8 bar is 1 inch diameter; grade 60 means 60 ksi yield.

A plan is a horizontal cut, a section is a vertical cut, an elevation is a flat exterior or interior view, and a detail is an enlarged view of a specific condition.

The authority having jurisdiction, not the designer, determines which code edition is enforceable on a given project.

Structural concrete is specified by 28-day compressive strength (commonly 3,000 to 5,000 psi) and water-cement ratio (commonly 0.40 to 0.50).

Air entrainment of roughly 5 to 7 percent provides freeze-thaw durability in exterior concrete.

Concrete typically reaches about two-thirds to three-quarters of its 28-day strength in 7 days at normal curing temperatures.

ASTM A992 is the standard grade for structural W-shapes with a 50 ksi minimum yield; A36 steel has a 36 ksi yield.

High-strength structural bolts are F3125 Grade A325 (120 ksi tensile) and A490 (150 ksi tensile); slip-critical connections require specified pretension.

Mortar types by compressive strength: M 2500 psi, S 1800 psi, N 750 psi, O 350 psi; Type S is used for structural and below-grade masonry.

Standard CMU is 8 by 8 by 16 inches nominal, with actual dimensions of 7-5/8 by 7-5/8 by 15-5/8 inches including the mortar joint.

Wood structural panels carry a span rating (for example 24/16), meaning 24 inches on supports for roof and 16 inches for floor.

BIM clash detection resolves MEP and structural conflicts in the model before installation, reducing field RFIs and rework.

A surety bond is a three-party instrument among surety, principal, and obligee; the surety's liability is limited to the bond penalty and the contractor indemnifies the surety.

Commercial general liability covers third-party bodily injury and property damage and excludes damage to the contractor's own defective work.

Builder's risk property insurance covers the structure under construction and typically excludes contractor's tools, equipment, and employee vehicles.

Workers' compensation is statutory and no-fault; it pays medical and lost-wage benefits and generally bars the injured employee from suing the employer.

On a work-in-progress schedule, costs and estimated earnings in excess of billings is an asset (underbilling); billings in excess of costs is a liability (overbilling).

Mechanic's lien rights are statutory and strictly time-limited; many states require a preliminary notice and recording within a fixed period after last furnishing labor or materials.

Prompt payment acts set statutory deadlines, often around 30 days, for paying construction invoices and define when interest begins to accrue.

Broad-form indemnity clauses that shift a party's own negligence are void or limited in many states; additional insured endorsements transfer risk another way.

Worker classification matters: misclassifying employees as independent contractors triggers payroll tax, workers' compensation, and penalty exposure.