NCMA Masonry Standards & ASTM C90Updated for 2026Commercial Grade

CMU Concrete Block Wall, Mortar & Grout Estimator

Calculate exact 8x8x16 concrete masonry blocks (CMU), courses, Type S mortar bags, and core fill pea gravel grout for retaining and foundation walls.

Regional Market Calibration:Adjusts trade labor, concrete mix, and building codes to local city averages.

Popular Dimension Presets:

Engineered Slab Cutaway Cross-Section (ACI 302)Slab Thickness: 4" Commercial Grade

Cross-section demonstrates structural reinforcement elevation on concrete chairs per ACI 302.

Project Dimensions & Material Inputs

Wall Length(ft)

Wall Height(ft)

CMU Block Width

Vertical Core Grouting

Total 8×8×16 CMU Blocks Required

213 Blocks (180 sq ft wall face)

Type S Mortar & Grout Fill

7 Bags Mortar | 0.5 yd³ Core Fill

Contractor Bill of Materials (BOM) Breakdown

Item / Material Spec	Quantity	Unit / Package	Installation Notes
Standard 8×8×16 Lightweight CMU Blocks	213	Blocks	Includes 5% cutting and corner waste
Type S Masonry Cement (80-lb bags)	7	Bags	Mixed at 1 part cement to 2.5 parts masonry sand
Fine Washed Masonry Sand	0.7	Tons	Clean aggregate for smooth 3/8-in bed and head joints
Coarse Core-Fill Grout (2,500 PSI)	0.5	Cubic Yards	Consolidates rebar cells per NCMA structural specs
#4 (1/2-in) Deformed Rebar for Vertical Cores	24	Pieces	Vertical dowels embedded into foundation footing

Estimated Project Cost Range (DIY vs. Turnkey Contractor)

National Average

DIY Raw Materials Only

$738 – $893

Cost of raw lumber, concrete, shingles, wire, or stone without equipment rentals or labor.

Licensed Contractor Turnkey

$3,240 – $5,040

Full installation: permits, site prep, skilled trade labor, equipment, and structural warranty.

Estimated Sweat Equity

~$3,325

Average trade labor savings if executed as a skilled DIY homeowner project.

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Standard CMU Face Area & Mortar Formula

Rendering formula...

Masonry Estimation for 30' Long × 6' High Block Wall

Wall Face Area = 30 ft × 6 ft = 180 sq ft.
Block Count Formula = 180 sq ft × 1.125 blocks/sq ft × 1.05 waste factor = 213 blocks.
Mortar Requirement: 213 blocks ÷ 100 × 3.0 bags = 7 bags Type S mortar.
Core-Fill Grout: Vertical rebar cells consolidated with 0.5 cubic yards of high-slump structural grout.

Engineering Tip: In National Average, structural block walls over 4 feet require vertical rebar every 32 inches and horizontal ladder wire every second course.

Quick Reference Sizing & Coverage Table

Standard commercial specifications and pre-calculated project benchmarks.

Pre-Calculated

Wall Length × Height	Courses High	8×8×16 CMU Blocks	Type S Mortar (80-lb Bags)	Turnkey Masonry Contractor Price
20 ft × 4 ft (80 sq ft)	6 Courses	95 Blocks	3 Bags	$1,600 – $2,400
30 ft × 6 ft (180 sq ft)	9 Courses	213 Blocks	7 Bags	$3,600 – $5,400
40 ft × 8 ft (320 sq ft)	12 Courses	378 Blocks	12 Bags	$6,400 – $9,600
60 ft × 8 ft (480 sq ft)	12 Courses	567 Blocks	18 Bags	$9,500 – $14,400

ASTM C90 Loadbearing Concrete Masonry Units / TMS 402 Building Code

ASTM C90 & TMS 402/602 Masonry Standards

Concrete masonry walls must be built upon a poured concrete footing below the frost line at twice the width of the block (16" wide for 8" CMU). Type S mortar (1,800 PSI minimum) is mandatory for at-or-below grade retaining and structural walls.

Frequently Asked Questions

How many concrete blocks are in a square foot of wall?

Including standard 3/8-inch mortar joints, one 8x8x16 CMU block covers 0.888 square feet. Therefore, there are 1.125 blocks per square foot of wall surface.

What type of mortar should I use for concrete block walls?

Use Type S mortar. It has a high compressive strength of 1,800 PSI and excellent flexural bond strength, making it the required standard for structural, foundation, and earth-retaining walls.

How many bags of mortar do I need for 100 blocks?

One 80-lb bag of pre-blended Type S mortar lays approximately 30 to 35 standard 8-inch blocks. For 100 blocks, you will need 3 to 4 bags.

Do you have to fill all concrete block cores with grout?

No. Non-bearing partition walls do not require full grout. Earth-retaining walls, however, require rebar and pea gravel grout core fill every 16, 24, or 32 inches on center according to structural load drawings.

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