Bond beam & lintel calculator (CMU)

1. Bond beam courses
   courses entered + one at each lintel level (head + 8")
   2 + 1 = 3
2. Bond beam length
   per course: wall length − openings it crosses − lintels (counted below), added up
   37 + 35.67 + 40 (ft) = 112' 8"
3. Bond-beam units
   per course: course length ÷ unit length, rounded up, added up
   444 ÷ 16 + 428 ÷ 16 + 480 ÷ 16 (in) = 85
4. Lintel length
   clear span + 2 × bearing
   3' 0" + 2 × 8" = 4' 4"
5. Lintel units
   lintel length ÷ unit length, rounded up
   52 ÷ 16 (in) = 4
6. Grout per foot of bond beam
   0.66 ft³ per bag ÷ LF per bag (TEK 4-2A Table 5)
   0.66 ÷ 2 = 0.330 ft³
7. Grout in bond beams
   bond beam LF × ft³ per LF
   112.67 × 0.33 = 37.18 ft³
8. Grout in lintels
   lintel LF × ft³ per LF
   4.33 × 0.33 = 1.43 ft³
9. Total grout
   bond beams + lintels
   (37.18 + 1.43) ft³ = 38.61 ft³
10. Cubic yards
    ft³ ÷ 27
    38.61 ÷ 27 = 1.43
11. Bags of grout (80 lb)
    ft³ ÷ ft³ per bag, rounded up
    38.61 ÷ 0.66 = 59
12. Lap length
    bar diameter × lap diameters
    #4: 0.5 × 48 (in) = 2' 0"
13. Bond-beam bars
    per course: bars × (run + laps × lap), added up
    2 × (37 + 1 × 2) + 2 × (40 + 2 × 2) + 2 × (40 + 2 × 2) (ft) = 254' 0"
14. Lintel bars
    bars × lintel length × openings (+ laps when longer than a stock bar)
    2 × 4.33 × 1 (ft) = 8' 8"
15. Weight
    feet × lb per foot (ASTM A615)
    262.67 × 0.668 = 175.5 lb
16. Stock bars
    full pieces + cut pieces packed into stock bars
    20' bars = 14

Where the numbers come from

• Bond beam courses: Top of wall + every 4' by default, plus the course right above each opening (the lintel course); the course is the 8" below the height you enterGeometry only — where bond beams go is on your structural drawings (typically the top of the wall, at floor and roof bearing, and over openings). A course that passes through an opening stops at the jambs, so that opening's width comes off its block and bars. The lintel course's block over the opening (clear span + 2 bearings) is counted under lintels; its bond-beam bars run on through a block lintel but stop at a precast one.
• Bond-beam and lintel units: Feet of course ÷ 16" (or 18"), rounded up; each replaces a standard blockNominal lengths include the ⅜" joint (ASTM C90 units are 15⅝" or 17⅝" long). Knock-out bond-beam units and open-bottom lintel (U) units are both counted here — order the kind your supplier carries. Cuts at jambs and corners come out of the rounding up; add waste for a cut-heavy wall.
• Lintel bearing: 8" each side by default (half a block); TMS 402 minimum bearing 4" in the direction of span (TMS 402-16 §5.2.1.3)NCMA TEK 17-1D: "minimum end bearing (4 in. (102 mm) typ.)", and its design example takes the effective span center-to-center of the two bearings (clear span + 4" when both bearings are 4": 5'4" + 4" = 5'8"). The Florida lintel product approval FL12193 (Marion Masonry) uses 8" of bearing for its load tables and allows 6½" for unfilled precast lintels: https://www.floridabuilding.org/upload/PR_Tech_Docs/FL12193_R7_AE_GLOBAL%20SEALED%20%20%20%20MARION%20MASONRY%2012-2024_v2%20(2).pdf. Follow the bearing on your drawings; the page warns below 4".Source
• Grout in bond beams: TEK 4-2A Table 5: one 80 lb bag (0.66 ft³) fills 2.7 LF of 6", 2.0 LF of 8", 1.6 LF of 12" bond beam → 0.244, 0.33, 0.4125 ft³ per LFThe same figure as the grout and CMU pages, turned into ft³ per foot (0.66 ÷ LF per bag) so any bag yield can be used. Lintels are taken at the same rate as bond beams. TEK has no figure for 10" block: 1.8 LF per bag (halfway between 8" and 12") is used with a warning until the owner gives a number.Source
• 80 lb bag of grout: Preblended 0.66 ft³ (TEK 4-2A Table 4 note); QUIKRETE Core-Fill Grout Coarse 1585-07 0.65 ft³, Fine 1585-08 0.68 ft³QUIKRETE data sheets (read 2026-10-19): "Each 80 lb (36.2 kg) bag of QUIKRETE Core-Fill Grout – Coarse will yield approximately 0.65 ft3 (18.4 L)" and "fill the cores of approximately 3 standard 8 in x 8 in x 16 in blocks"; Fine: 0.68 ft³ (http://www.quikrete.com/pdfs/data_sheet-core-fill-grout-fine-1585-08.pdf). Pick the bag on the page or type your own yield. Ready-mix grout is ordered by the CY.Source
• Lap length: 48 bar diameters for Grade 60 (#4 = 24", #5 = 30", #6 = 36")The IBC 2107.2 alternative for allowable stress design, as summarized by ENERCALC: 40 diameters for 40 ksi bars, 48 for 60 ksi — the same rule as the CMU rebar page. TMS 402's development-length equation can give longer laps; use the lap on your structural drawings when it is given.Source
• Horizontal bars: 2 #4 per bond beam course and 2 #4 per lintel by default; a bar longer than a stock piece is lappedBars run the length of each course between openings (continuous through block lintels). Each extra stock piece adds (piece − lap) of reach: pieces = ⌈(run − piece) ÷ (piece − lap)⌉ + 1. Lintel bars run the full lintel length (clear span + 2 bearings). Bar size and count are your engineer's — TEK 17-1D tables run 1 or 2 bars, #4 to #6.
• Corner bars: One bent corner bar per bond-beam bar per course at each corner, two legs of one lap eachA common detail: a bent bar in the bond beam at each corner, lapped with the straight bars both ways. Enter 0 if your bars are bent around the corner instead (no extra steel). Owner question: confirm this detail.
• Rebar weights (ASTM A615): #4 0.668 · #5 1.043 · #6 1.502 lb/ftThe same table the rebar calculator uses: bar area × 3.40 lb/ft per in².Source
• Stock bars: Lapped bars use full stock pieces plus a cut piece; cut pieces are packed into stock bars longest firstOffcuts that fit another cut piece are reused. Waste, if entered, is added to the stock bar count and the grout only.