NE General Contractor cheat sheet

Nebraska contractor license types: General Contractor (unlimited), Building Contractor (limited scope), and Specialty Contractor categories administered by the Nebraska Department of Labor's Contractor Registration program.

Contractor registration is required for projects over $5,000 (labor and materials combined); registration is not a competency exam but failure to register bars enforcement of the contract and permits penalties.

Nebraska requires a separate Electrical Contractor, Master/Journeyman Electrician license through the State Electrical Division, and plumbing licensure through local jurisdictions or the state plumbing board.

Nebraska Workers' Compensation coverage is mandatory for employers with one or more employees; sole proprietors and partners may elect coverage but corporate officers are counted.

Nebraska's 5-year statute of repose for construction defects (Neb. Rev. Stat. § 25-223) limits claims arising from defective design or construction of improvements to real property.

Mechanics' lien: a contractor must file a lien within 120 days after last furnishing labor or materials; a subcontractor must give a preliminary notice to the owner within 10 days of first furnishing.

Nebraska Prompt Payment Act: public owners must pay within 30 days of a proper invoice; retainage on public projects is limited and must be released within 30 days of final acceptance.

Business entity selection affects liability: a corporation or LLC shields personal assets, but Nebraska requires foreign entities to register with the Secretary of State and maintain a registered agent.

Contract types: lump sum (fixed price, risk on contractor), unit price (quantity risk on owner), cost-plus (owner bears cost risk), and GMP (cost plus with a guaranteed maximum and shared savings).

Bid documents must be acknowledged by addendum; failure to acknowledge an addendum on the bid form is grounds for bid rejection as nonresponsive.

Bid bond typically 5-10% of bid; performance bond and payment bond each typically 100% of contract amount on public work.

Critical path method (CPM): total float = LS - ES = LF - EF; an activity on the critical path has zero total float and any delay there extends project completion.

Change order vs. construction change directive: a CCD directs work before price agreement; a change order is a signed agreement to scope, price, and time.

Substantial completion triggers warranty start, retainage release provisions, and owner's right to occupy; punch list items must be completed within a stated period.

Schedule of values and pay applications: progress payments are based on percentage of work in place; retainage typically 5-10% until substantial completion.

Liquidated damages are a pre-estimated per-day amount for delay; they must be a reasonable forecast, not a penalty, to be enforceable.

Scale conversion: at 1/4" = 1'-0", one inch on the drawing equals 4 feet; at 1/8" = 1'-0", one inch equals 8 feet.

Waste factors: lumber 10-15%, concrete 5-10%, masonry 5-7%, roofing 10-15%, drywall 10-12%, tile 10-15% - applied to net quantities.

Concrete volume: length × width × depth in feet ÷ 27 = cubic yards; add 5% for spillage and uneven subgrade.

Specification divisions follow CSI MasterFormat 50 divisions; Division 01 is General Requirements, Division 03 Concrete, Division 05 Metals, Division 09 Finishes.

Plan symbols: dashed line = hidden/overhead; solid = visible; section markers show drawing and detail reference; north arrow and benchmark establish orientation and elevation.

Quantity takeoff sequence: review all drawings and addenda, measure by trade, apply waste, price labor and material separately, then add overhead and profit.

Contingency in estimates: design contingency (5-10% during design), construction contingency (3-5% during construction), and escalation for inflation on long projects.

Bid strategy: unbalanced bidding shifts costs to early or high-quantity items; front-end loading improves cash flow but may be rejected as nonresponsive.

Fall protection required at 6 feet in construction (29 CFR 1926.501); guardrails, safety nets, or personal fall arrest systems are acceptable.

Scaffold requirements: top rail 38-45 inches, midrail approximately 21 inches, toe board 3.5 inches; scaffold must support 4 times intended load.

Excavation: protective system required at 5 feet depth; spoil pile and equipment kept at least 2 feet from the edge; ladder every 25 feet of lateral travel.

Ladder angle: 4:1 ratio (1 foot out for every 4 feet up); extend 3 feet above landing for access to roofs.

Cranes: load chart must be in cab, swing radius barricaded, and 10-foot minimum clearance from power lines (or de-energize and ground).

Hazard Communication (HazCom) requires Safety Data Sheets (SDS) for each hazardous chemical and labeling of all containers.

Personal protective equipment: hard hats, safety glasses, and ANSI-rated footwear on all active construction sites; hearing protection at 85 dBA TWA.

Recordkeeping: OSHA 300 log required for employers with 11+ employees; fatalities reported within 8 hours, hospitalizations/amputations within 24 hours.

Soil classification: granular soils (gravel, sand) drain well and have high bearing capacity; cohesive soils (clay, silt) are subject to frost heave and shrink-swell.

Standard Proctor (ASTM D698) vs. Modified Proctor (ASTM D1557): modified uses greater energy and yields higher maximum dry density; field compaction typically specified to 95% of modified.

Concrete mix: water-cement ratio controls strength and durability; 0.45-0.50 w/c for typical structural concrete; lower w/c = higher strength and lower permeability.

Concrete cure: 7 days moist curing for Type I cement; cold weather requires heated enclosure and protection below 40°F; hot weather requires cooling and evaporation control.

Rebar: #4 bar = 1/2 inch diameter; #5 = 5/8 inch; #8 = 1 inch. Development length and cover per ACI 318 (typically 1.5-3 inches depending on exposure).

Footing types: spread footing (isolated), combined footing, mat/raft foundation (large loads, weak soils), and deep foundations (piles, drilled shafts, caissons).

Concrete testing: slump test (ASTM C143) for workability; air content by pressure meter; compressive strength by 6x12 or 4x8 inch cylinders at 7 and 28 days.

Drainage: footing drains at base of footing, sloped to daylight or sump; waterproofing on below-grade walls (membrane or fluid-applied) and gravel backfill.

Concrete masonry unit (CMU) nominal 8x8x16 inches; actual 7-5/8 x 7-5/8 x 15-5/8; mortar joint 3/8 inch.

Brick modular: 3-5/8 x 2-1/4 x 7-5/8 inches; running bond offsets each course by half a brick; common bonds: running, Flemish, English, stack.

Mortar types: Type M (highest strength, below grade), Type S (moderate-high, typical exterior), Type N (general purpose above grade), Type O (low strength, interior non-load-bearing).

Wall ties: corrosion-resistant ties every 16 inches horizontally and 24 inches vertically; flashing and weep holes at base of cavity walls.

Wood framing: nominal 2x4 is 1.5 x 3.5 inches; 2x6 is 1.5 x 5.5; 2x10 is 1.5 x 9.25; framing spacing 16 or 24 inches on center.

Floor joists: maximum span depends on species, grade, and spacing; bridging or blocking at midspan for spans over 8 feet; rim joist and subfloor glued and nailed.

Roof framing: rafters, ridge board, collar ties (upper third of rafter), and ceiling joists to resist thrust; hip vs. gable roof geometry.

Sheathing: OSB or plywood rated by span rating (e.g., 24/16); nailed at 6 inches on center at edges, 12 inches in field; panel edges must fall on framing.

Roof slope: low slope is 2:12 or less; steep slope is greater than 4:12; underlayment requirements differ by slope and product.

Asphalt shingles: minimum 4:12 slope for standard installation; double underlayment for slopes 2:12 to 4:12; ice dam membrane required at eaves in cold climates.

Built-up roofing (BUR): alternating layers of felt and bitumen; 4-ply typical; flood coat and gravel surfacing; requires a vapor retarder and insulation board.

Single-ply membranes: EPDM (thermoset, seamed with adhesive or tape), TPO and PVC (thermoplastic, heat-welded).

Flashing types: base flashing, counterflashing, step flashing at sidewalls, and cricket at chimneys wider than 30 inches.

Vapor retarder placement: on the warm side of insulation in cold climates to prevent condensation within the assembly.

Insulation R-values: rigid foam board (polyiso ~R-6 per inch, XPS ~R-5, EPS ~R-4), fiberglass batt (~R-3.1 per inch), spray polyurethane (~R-6 to R-7 per inch).

Air barrier continuity: seal penetrations, top plates, and rim joists; blower door test measures air changes per hour (ACH50) to verify performance.

HVAC tonnage: one ton of cooling = 12,000 BTU/hour; rule of thumb 1 ton per 400-600 square feet depending on climate and envelope.

Duct sizing: velocity method (fpm) or equal friction method; supply trunk velocities typically 600-900 fpm for residential, higher for commercial.

Refrigerant cycle: compressor → condenser (rejects heat) → expansion valve → evaporator (absorbs heat); SEER2 and HSPF2 are efficiency ratings.

Electrical: Ohm's law V = I × R; power P = V × I (single-phase); P = √3 × V × I × PF for three-phase.

Ampacity and derating: conductors sized per NEC 310.16; derate for ambient temperature and more than 3 current-carrying conductors in a raceway.

GFCI required in bathrooms, kitchens, outdoors, garages, and within 6 feet of sinks; AFCI required in bedrooms and living areas per NEC.

Plumbing: drain slope 1/4 inch per foot for 2-inch and smaller pipe, 1/8 inch per foot for 3-inch and larger; vent stack extends above roof.

Water supply: typical pressure 40-80 psi; pressure-reducing valve above 80 psi; backflow preventer required at connections to potable supply.

Gypsum board types: regular, Type X (fire-rated, 5/8 inch), moisture-resistant (green board, for bathrooms), and abuse-resistant for high-traffic areas.

Drywall finishing levels 1-5: Level 4 is standard for painted surfaces; Level 5 requires a skim coat for critical lighting conditions.

Fire-rated wall assemblies: 1-hour rating often achieved with 5/8 inch Type X on each side of steel studs; 2-hour requires additional layers or specific UL designs.

Door types: hollow-core (interior, lightweight), solid-core (interior, better acoustics), and hollow metal (commercial, fire-rated).

Door hardware: standard locksets, panic hardware required on egress doors serving 50+ occupants; closers required on fire doors.

Window ratings: U-factor measures heat loss (lower is better); SHGC measures solar heat gain; VT is visible transmittance; NFRC labels verify performance.

Glazing: insulated glass units (IGU) with low-E coatings and argon fill; tempered glass required in hazardous locations (doors, within 24 inches of floor, large panels).

Tile and flooring: ceramic vs. porcelain (porcelain lower absorption); hardwood expansion gaps at walls; carpet cushion and tack strip installation.