Introduction
The lumber yard is the wrong place to discover a missing input. A joist order placed with an unverified span, a forgotten hardware line, or a mixed-unit count means a second delivery at best and a failed inspection at worst. This checklist is the pre-order pass: every span, count, size, and accessory verified before money changes hands.
Run your dimensions through the Floor Joist Calculator first for the quantities, then walk this list line by line.
Dimensions and Layout
- Floor area measured twice — each dimension at both ends; larger reading used for the run.
- Measured to bearing faces — inside faces of walls/beams, not outside of foundation.
- Joist direction decided and sketched — normally the shorter dimension, confirmed by bearing locations.
- Out-of-square noted — the last bay absorbs it; rim splices planned over joists.
- Openings located — stairs, hatches, chases marked; header/trimmer pieces estimated separately.
- One unit system throughout — no feet/inches or ft/m mixing in the takeoff.
Span and Spacing
- Span verified in the correct span table — species, grade, size, spacing, and load case all match the actual lumber (IRC Table R502.3.1 or supplier charts; manufacturer tables for I-joists). The lookup method is in the formula guide.
- Spacing selected deliberately — 16″ o.c. (400 mm) default; 12″ (300 mm) for tile/heavy loads; 19.2″ (488 mm) for I-joists; 24″ (600 mm) light duty only.
- Deflection considered — L/360 live-load limit satisfied; tile floors get tighter spacing or deeper joists.
- Beam option priced — for spans past ~16 ft, a mid-span beam was compared against deeper joists or I-joists.
- Point loads identified — tubs, safes, pianos, masonry: doubled joists or beams designed, not assumed.
The Count
- Joist count from the run — (run ÷ spacing) + 1, rounded up; run is the dimension perpendicular to joist direction.
- +1 starter joist included — the classic off-by-one checked.
- 2 rim joists added — full depth, same size; splice locations planned over joists.
- Blocking counted — one block per bay per required row (bays = joists − 1); mid-span row minimum, second row for long spans.
- Joist length = span + bearing both ends — 1.5″ (38 mm) minimum per end on wood, 3″ (76 mm) on masonry — rounded up to next standard stock length.
- Waste allowance added — 5–10% on joist count for culls and cutting (higher end for 18–20 ft stock).
- Calculator cross-check done — the Floor Joist Calculator result matches the hand count.
Lumber
- Size, species, and grade specified — matching the span table read (e.g., 2×10 SPF #2, not just “2×10s”). Species/grade options are compared in the material guide.
- Stock lengths chosen — next standard length above needed cut; one consistent length for the field joists.
- Rim stock sized — longest spliceable pieces covering 2 × run length.
- Blocking source planned — offcuts first; short stock only for the shortfall.
- Sill plates and beams on the list — the joist takeoff is not the whole order; plates, beams, and posts are separate lines.
- Moisture spec confirmed — S-DRY (≤19%) for joists; treated stock only where ground contact requires it.
Hardware and Fasteners
- Joist hangers counted — one per supported joist end where joists frame into beams/ledgers; size matched to joist.
- Hanger nails specified — manufacturer-specified joist nails (1-1/2″), quantity per the hanger schedule; never substituted with roofing nails or screws unless rated.
- 16d nails for rims and blocking — ~3 per joist end into rims; ~4 per block.
- Subfloor adhesive — ~1 tube per 2 bays.
- Sill plate anchors/bolts — per code and the foundation plan.
- Corrosion rating checked — hot-dip galvanized or stainless wherever treated lumber is used.
Tools and Site
- Cutting and fastening tools ready — circular saw, framing hammer or nailer + compressor, chalk line, levels, squares, sawhorses, PPE.
- Help arranged — 14 ft+ joists are two-person work; longer stock needs three.
- Lumber storage planned — covered, stickered, off the ground; cut ends protected from standing water.
- Crown-marking supplies — lumber crayon for marking crown-up on every joist before setting.
Code and Inspection
- Permit in hand — structural framing permitted before work starts; framing plan matches the takeoff.
- Rough inspection scheduled — before subfloor or insulation closes the system.
- Notching/drilling zones communicated — mechanical trades know the legal zones (no notches in middle third; holes per R502.8); I-joist hole charts on site if applicable.
- Fire blocking planned — rim cavities and concealed spaces blocked per R302.11 or local equivalent.
- AHJ questions asked — local amendments, draft-stopping, and inspection specifics confirmed with the building department. Code background is in the code compliance guide.
Budget
- Full system priced, not joists only — rims, blocking, hangers, nails, adhesive included (typically +30–50% over the bare joist line).
- Two supplier quotes — lumber prices move; quotes within a week of purchase.
- Delivery scheduled — long stock needs appropriate truck access and on-site handling.
- Contingency held — 10% over the material total for price movement and the inevitable extra trip.
The pricing method behind the budget lines is worked through in the cost guide, and the full method in the complete guide.
Related Guides
- Floor Joist Calculator Complete Guide — the full how-to with a complete worked example.
- Floor Joist Estimating Guide — step-by-step measuring and takeoff.
- Floor Joist Cost Guide — turning the takeoff into a budget.
- Floor Joist Common Mistakes — the errors this checklist prevents.
- Floor Joist Pro Tips — installation craft for the build day.
- Floor Joist Calculator FAQ — quick answers to the most asked questions.
Frequently Asked Questions
What is the most commonly forgotten item on a joist order?
Hardware — hangers, hanger nails, and adhesive. Second most common: the rim joists themselves, when the takeoff only counted field joists.
How much extra lumber should I order?
5–10% over the joist count for culls and cutting waste — use the higher end for 18–20 ft stock, which culls more for bow and twist.
Should I verify the span before or after counting?
Before. The count is meaningless if the joist size can’t legally cross the span — verify span in the table, then count, then order.
Do I need the permit before ordering lumber?
Order after the permit is approved, not before — the approved framing plan is what the takeoff must match, and plan review sometimes changes sizes or spacing.
Get Your Number
Print this page, run the Floor Joist Calculator for your quantities, and check off every line before you call the yard. The ten minutes it takes is the cheapest insurance in the whole project.
Disclaimer: Calculator results are planning estimates based on the dimensions you enter. Floor framing is structural work — joist sizes, spans, and spacings must comply with your local building code and approved span tables. Consult a licensed professional or your local building authority before building, and verify all takeoffs with a qualified framer.
