S F Johnson Consulting, LLC
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Concrete Cheat Page

Concrete Cheat Page

Welcome to ConstructIQ™ — Trade-Specific Training & Certification

Build. Learn. Preserve. Our platform delivers customized, trade-specific study programs with weekly videos, quizzes, tests, and certifications. Explore our full ecosystem below and claim $100 OFF any class.

Trade Programs

Electrical, HVAC, Plumbing, Civil, Structural, Architectural, Fire Protection.

E-Deck Estimator

Man-hour calculators & take-off tools by trade to price work with confidence.

Project Management

Scheduling, RFIs, submittals, closeout, and field coordination workflows.

Safety / OSHA

Toolbox talks, OSHA 1926 standards modules, and certification paths.

License Reciprocity

Multi-state licensing, paperwork guidance, and exam support.

Intern Academy

9-month training tracks with quizzes, tests, and progress reviews.

Questions? info@sfjohnsonconsulting.com • 844-261-9737

🧱 Concrete & Masonry Cheat Sheet

Essential references for foundations, slabs, block walls, rebar, and takeoff calculations.

🔎 Plan Symbols

  • Concrete hatch: stipple or dot pattern.
  • Masonry block: diagonal cross-hatch (CMU walls).
  • Rebar: single line with bar callout (#4, #5, etc.).
  • Footings: bold outline with section callouts.
  • Control joints: dashed lines across slab.
  • Masonry bond beam: shaded course in wall elevation.

📐 Key Calculations

  • Concrete volume: length × width × thickness ÷ 27 = cubic yards.
  • Block count (8×8×16): wall SF ÷ 1.125 ≈ # of blocks.
  • Mortar bags: 1 bag per 35–40 blocks (typical).
  • Rebar spacing: wall height ÷ spacing = bars per vertical run.
  • Brick count (modular): wall SF × 7 = # of bricks.
  • Grout volume (CMU walls): wall SF × thickness factor ÷ 27.

⚡ Quick Reference

  • 📏 Slab thickness: 4" residential, 6"+ commercial.
  • 🪢 #4 rebar: ½" dia, 0.20 in² area.
  • 🧱 CMU sizes: 8×8×16 nominal (7 ⅝" actual).
  • 🧱 Brick modular size: 3 ⅝" × 2 ¼" × 7 ⅝".
  • 🧰 Concrete yield: 1 yd³ = 27 ft³ ≈ 81 50-lb bags of ready-mix.
  • 🔨 Control joint spacing: 24–36 × slab thickness (inches).

📝 Self Test

  1. How many cubic yards of concrete are needed for a 20' × 30' slab at 6" thick?
  2. How many 8×8×16 CMU blocks are required for a 100 SF wall?
  3. How many bricks are needed for a 250 SF veneer wall?
  4. What is the diameter of #4 rebar?
  5. What spacing rule is used for slab control joints?

(Answers: 1) 20×30×0.5 ÷ 27 ≈ 11.1 CY, 2) 100 ÷ 1.125 ≈ 89 blocks, 3) 250 × 7 ≈ 1,750 bricks, 4) ½", 5) 24–36 × thickness)