Red Seal Carpenter cheat sheet

Occupational fall protection is required at 3 m (10 ft) in general construction; guardrails, personal fall arrest, or a written fall protection plan must be in place before work begins above that height.

A personal fall arrest system limits maximum arresting force to 8 kN (1,800 lbf) and must keep the free-fall distance to 1.8 m (6 ft) or less with a shock-absorbing lanyard.

Full-body harness anchor points must support 22 kN (5,000 lbf) per worker; horizontal lifelines require design by a qualified person.

A portable ladder must extend at least 1 m (3 ft) above the landing and be set at a 4:1 slope; secure it at the top and every 9 m (30 ft) for fixed access.

Scaffold platforms require toe boards when workers below are exposed, a complete guardrail system at 0.9-1.1 m (36-42 in), and a mid-rail at approximately half that height.

Silica dust from cutting concrete, masonry, or fibre-cement requires wet cutting or a dust-collection shroud; respirators alone are the last line of defence.

Hazardous energy control (lockout) applies before servicing saws, compressors, or hoists; verify zero energy state and tag the lock with the worker's name.

WHMIS/safety data sheets must be available on site for every controlled product; formaldehyde in panel goods and isocyanates in spray foam are common sensitizers.

A circular saw blade should project no more than one tooth depth (about 6 mm / 1/4 in) below the material; a dull blade raises kickback risk and burn marks.

Kickback is reduced by supporting the off-cut, keeping the blade guard functional, and standing to the side of the blade line, never in line with it.

A mitre saw crosscuts to a maximum width set by the saw; for wide stock use a radial arm saw or a circular saw with a straight edge.

Powder-actuated fasteners require the correct cartridge colour for base material; never fasten into cast iron, hardened steel, or hollow block without a tested application.

A nail gun must be fitted with a contact (tip) safety; never hold the trigger down and bump-fire, and disconnect air before clearing a jam.

Laser levels and rotary levels should be checked for calibration on a known level line before layout; error doubles over the distance to the target.

A reciprocating saw with a bimetal blade cuts nails in lumber; a carbide blade is required for cast iron, masonry, and fibreglass.

Torque values for structural bolts and lag screws come from the engineered drawings or manufacturer tables; impact drivers must not be used to set structural bolts to final torque.

Architectural drawings show finishes and dimensions; structural drawings govern member sizes, connections, and load paths. The structural drawing controls when the two conflict.

The written specification supersedes the drawing notes for materials, finishes, and workmanship; the drawing governs geometry.

A scale of 1:50 means 1 unit on paper equals 50 units in reality; verify with a known dimension before scaling anything off a drawing.

Grid lines and benchmarks are the reference for all layout; establish a site benchmark tied to a permanent elevation before excavation.

A takeoff quantity = net length x width x thickness, with waste added: 5-10% for framing lumber, 10% for sheet goods, 10-15% for siding and roofing.

A change order must be written, priced, and signed before the work is performed; verbal direction is confirmed in writing the same day.

Shop drawings for trusses, stairs, and cabinetry are reviewed against the architectural drawings for opening sizes, swing, and headroom before fabrication.

The 3-4-5 method (or 6-8-10) squares a corner; for large buildings use the diagonal method: both diagonals of a rectangle must be equal.

Building layout starts from the property line and the setback required by the by-law; the building corner is set from the survey plan, not scaled from a drawing.

Batter boards are set outside the excavation and string lines are transferred to them; the strings mark the building face and are checked for square by diagonals.

Excavation depth = footing depth plus footing thickness plus slab or crawlspace depth; check the geotechnical report and frost depth for the jurisdiction.

Footings must bear on undisturbed soil or compacted granular fill; organic material and loose fill are removed before forming.

Granular base under slabs is compacted in lifts of 150 mm (6 in) and tested; a vapour barrier of 0.15 mm (6 mil) polyethylene laps 150 mm (6 in) at joints.

A builder's level or laser establishes the elevation datum; all footing, slab, and floor elevations are referenced to a single benchmark.

Drainage is graded away from the building at a minimum 2% slope for the first 3 m (10 ft) unless a drainage system is designed.

Site services (water, sewer, power) are located and marked before excavation; call the utility locate service at least two working days ahead.

Formwork design load includes concrete weight (about 24 kN/m3 or 150 lb/ft3), plus live load, impact, and the pressure of fresh concrete, which depends on pour rate and temperature.

Form deflection is limited to 1/360 of the span for exposed concrete and 1/270 for hidden surfaces; camber is built in for long spans.

Wall form ties are spaced to resist lateral pressure; the tie capacity and spacing come from the formwork designer, not from habit.

Form release agent is applied to clean forms before the first pour and reapplied after each use; excess oil stains the concrete face.

Formwork is not stripped until concrete reaches the specified strength: typically 70% of design strength for soffits and 100% for post-tensioned or cantilevered members, confirmed by cylinder tests.

Formwork tolerances: vertical alignment within 6 mm in 3 m (1/4 in in 10 ft); floor flatness within 6 mm in 3 m under a 3 m straightedge.

Construction joints are located at one-third points of spans where possible and are keyed and cleaned before the next pour.

Form bracing must resist wind and pour pressure; diagonal braces are anchored to a solid base and not to backfill or loose material.

Floor joist span tables depend on species and grade, joist size, spacing, and live load (typically 1.9 kPa / 40 psf for residential floors).

Joist bearing on wood or metal is at least 38 mm (1.5 in); bearing on masonry is at least 89 mm (3.5 in).

Holes in solid sawn joists: maximum diameter one-third of the joist depth, located in the middle third of the depth, not closer than 50 mm (2 in) to the edge; notches only in the top or bottom at the ends.

Wall studs are spaced at 400 mm (16 in) or 600 mm (24 in) on centre; a stud is notched no more than 25% of its width and bored no more than 40% of its width.

Roof pitch = rise / run; the slope ratio (e.g., 4:12) gives the rafter length factor: total rafter length = run / cos of the pitch angle, plus overhang.

Ceiling joists and rafters are tied together at the ridge and at the wall plate; collar ties or a ridge beam prevent wall spread.

Bracing: let-in or metal T-bracing is required on at least one wall line at each end and at intervals not exceeding 7.6 m (25 ft) for walls over 2.4 m (8 ft) high.

Sheathing panels are installed with the long dimension across supports and staggered; panel edges are nailed at 150 mm (6 in) and field nails at 300 mm (12 in) for walls.

Roof underlayment laps: 100 mm (4 in) on side laps and 50 mm (2 in) on end laps for #15 felt; ice dam membrane extends at least 900 mm (36 in) up from the exterior wall line.

Asphalt shingles: minimum 4 nails per shingle, 6 in high-wind zones; starter course at the eave and a 140 mm (5.5 in) exposure for standard 3-tab shingles.

Flashing sequence: underlayment, then step flashing woven with each shingle course, then counter-flashing over the wall cladding. Water must always run over, never behind, the metal.

Siding requires a drained and ventilated cavity or a weather-resistive barrier with laps shingled in the direction of water flow; minimum 200 mm (8 in) clearance from grade to siding.

Windows are set plumb and level, shimmed at the sill and head, and flashed with a sloped sill pan; the rough opening is 12-25 mm (1/2-1 in) larger than the unit.

Exterior doors require a sill pan or pan flashing, back-dam, and head flashing; the threshold sits above the exterior finish line.

Ventilation is required for attic spaces: 1 sq ft of free vent area per 150 sq ft of ceiling area, split between soffit and ridge (1/300 with a vapour barrier).

Fasteners for exterior trim must be galvanized or stainless when in contact with treated wood; standard steel corrodes in treated lumber.

Drywall screws are spaced 300 mm (12 in) on ceilings and 400 mm (16 in) on walls, with screws set just below the paper surface without breaking it.

Drywall joints are staggered between courses and offset at least 600 mm (24 in) from the opposite side; butt joints are avoided where possible.

Thermal insulation is installed in full contact with the air barrier; a 20 mm (3/4 in) gap in batt insulation can reduce R-value by up to 50%.

Vapour barrier goes on the warm side of the insulation; in cold climates, that is the interior side, with joints lapped and sealed.

Door slabs require a 3 mm (1/8 in) gap at the sides and top and a 12-19 mm (1/2-3/4 in) undercut for return air.

Stair geometry: maximum riser 200 mm (7-3/4 in) and minimum tread 255 mm (10 in) for residential; the unit rise must be consistent within 6 mm (1/4 in) over the flight.

Cabinets are set level and plumb with shims at the wall, screwed to studs through the hanging rail; base cabinet height is 900 mm (36 in) with a 600 mm (24 in) depth.

Level 4 drywall finish is the standard for painted walls; Level 5 with a skim coat is specified where critical lighting will reveal joints.

Before demolition, identify non-load-bearing partitions from the structural drawings; a wall is load-bearing if it supports a joist, beam, or roof member above.

Temporary shoring is designed by a qualified person before a load-bearing wall is removed; the load path is transferred to temporary posts and beams.

Hazardous materials surveys are required before disturbance in buildings of certain ages: asbestos in pre-1990 materials, lead paint in pre-1978 housing, and mould in water-damaged areas.

Existing framing is inspected for rot, insect damage, and undersized members before new loads are added; sistering or reinforcement is specified by an engineer.

Matching existing finishes: measure existing profiles and take a sample of trim, siding, and flooring to source a match; paint colour is matched to a sample, not to a name.

Renovation tolerances are tighter than new construction; the new work must meet the existing surface, so layout starts from the existing condition, not from a grid.

Dust control uses negative air pressure with HEPA filtration and sealed poly barriers; a zipper door keeps the barrier serviceable.

Permits are required for structural changes, additions, and most plumbing and electrical work; the permit is posted on site before work starts.

Stair formula: 2 risers + 1 tread = 600-640 mm (24-25 in); the number of risers = total rise / desired riser, rounded up, then the exact unit rise = total rise / number of risers.

Stringer length = square root of (total rise squared + total run squared); the run = number of treads x unit tread depth.

Headroom over stairs must be at least 1.95 m (6 ft 8 in) measured vertically from the nosing line; handrail height is 865-965 mm (34-38 in).

A deck ledger is flashed with a Z-flashing above and a bead of sealant, and is fastened to the rim joist with lag screws or through-bolts sized by the deck design.

Deck footing size and depth come from the frost depth and the tributary load; post-to-footing connections must resist uplift.

Deck guardrails: minimum height 900 mm (36 in) for residential, with balusters spaced so a 100 mm (4 in) sphere cannot pass, and a bottom rail not more than 100 mm above the deck.

Deck joists are sized from the span table for the deck live load (typically 1.9 kPa / 40 psf) and the joist spacing; cantilever is limited to one-quarter of the back span.

Stair treads and risers must be dimensionally uniform within 6 mm (1/4 in); the greatest riser height minus the smallest may not exceed 9 mm (3/8 in).