Joint reinforcement calculator (truss / ladder)

1. Rows of joint reinforcement
   (wall height − first course) ÷ row spacing, rounded up
   (96 − 8) ÷ 16 (in) = 6
2. Pieces in one row
   (wall length − piece) ÷ (piece − lap), rounded up, + 1
   (100 − 10) ÷ (10 − 0.5) (ft), rounded up, + 1 = 11
3. Straight pieces
   rows × pieces per row
   6 × 11 = 66
4. Wall length covered
   rows × wall length
   6 × 100 (ft) = 600' 0"

Where the numbers come from

• Rows: First row in the bed joint on top of course 1, then every row spacing; the top of the wall is not a bed jointMiami-Dade Water & Sewer spec 04082: joint reinforcement every second course (16" vertical), "commencing at the first course above footings". 8' wall, 8" block, 16": (96 − 8) ÷ 16 = 5.5 → 6 rows. Rows broken by openings are not taken off.Source
• 16" maximum: Truss or ladder at 16" o.c. or closer, with control joints at industry spacing, resists shrinkage crackingThe Masonry Society, "TMS Responds" Vol. 18 No. 1. Truss diagonals cross the cells and can get in the way of vertical bars — ladder is the usual choice for reinforced walls.Source
• Pieces and laps: 10' pieces; laps at least 6" (H&B ladder allows a full 8" splice)Hohmann & Barnard 220 Ladder-Mesh: "Packed 500' per bundle (50 pcs. – 10' long)". Lap 6" minimum per the Miami-Dade spec (splices wired, overlap at least 6"). A run longer than a piece takes ⌈(L − piece) ÷ (piece − lap)⌉ + 1 pieces.Source
• Corners and tees: One prefabricated corner or tee per row at each corner and wall intersectionPrefab sections keep the reinforcement continuous around corners (Miami-Dade 04082, 3.01 C). Their legs are not taken off the straight pieces, so the straight count runs a little high.