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BLOCK WALL
CALCULATOR.

For CMU (cinder block) walls — retaining walls, foundation walls, garden walls. Calculate block count, mortar, concrete fill, footing concrete, and installed cost.

Your Wall

Block walls over 4 feet tall require structural engineering and a permit. We handle both.

ft
ft

Standard 8"x8"x16" CMU is most common. Walls retaining soil require structural engineering above 4 feet. We coordinate engineering and permits.

Your Wall Needs

40' × 4' wall, 8" CMU

Wall Face Area
160 sqft
180 blocks needed (incl. 5% waste)
Mortar
9 × 80lb bags
Type S mortar, ~3 bags per 100 blocks
Concrete Fill
1.2 cy
All cells filled — structural wall
Footing Concrete
1.6 cy
Standard 24"×8" footing below frost line
Peak Concrete Installed Cost
$4,800 – $12,800
160 sqft of wall face — includes engineering coordination, permit, footing, blocks, mortar, fill, rebar, drainage.
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Pro Tip

Drainage behind the wall is what separates a 30-year wall from a 5-year wall. Always pipe behind the base course in free-draining gravel. We do this on every install.

Block Wall Calculator FAQ

BLOCK WALL QUESTIONS.

How tall can I build without a permit?

Most Northern Utah jurisdictions: 4 feet from grade to top of wall, no permit. Above 4 feet: structural engineering and permit required. We handle both.

How many blocks per square foot of wall?

Standard 8"x8"x16" block: 1.125 blocks per sqft of wall face. So a 100 sqft wall = ~113 blocks (we order 5% extra for breakage).

Should I fill all the cells with concrete?

Structural retaining walls and foundation walls: yes, all cells with rebar (#4 or #5 vertical bars at 24-32" spacing). Decorative garden walls: no, just the corners and bond beam. Partial fill is for moderate-load walls.

What about drainage behind a retaining wall?

Critical. Always: 1) perforated drain pipe at base, 2) free-draining gravel backfill (12+" deep), 3) geotextile fabric separating gravel from soil. Without this, hydrostatic pressure pushes the wall over within 5-10 years.

CMU block vs decorative segmental block (Versa-Lok, Allan Block)?

CMU is structurally stronger and cheaper per sqft, but needs facing or stucco for finished look. Versa-Lok / Allan Block is finished on the face, faster install, more expensive. Both work; CMU is more common for foundation walls, segmental for landscape retaining.

How long does install take?

A 100-150 sqft wall: 5-10 working days including footing pour and cure time. Larger walls scale up. Engineered walls add 2-4 weeks of permit/engineering time.

READY FOR A REAL QUOTE?

Free on-site consult. Itemized quote within 48 hours.

Request a Quote Call 801-661-7000