By Zencalcy Editorial TeamLast reviewed About us
Hollow block walls are often filled with grout for strength, fire resistance or anchor capacity. Only the cores are filled, so the volume is a fraction of the wall — roughly 0.2 cubic feet per 8 × 8 × 16 block, more for larger blocks and less when rebar takes up space.
Grout to fill the cores of a hollow block wall.
Blocks = area ÷ block face Grout = blocks × fill per block
Standard 8 × 8 × 16 inch block covers 0.888 sq ft and holds about 0.2 cu ft of grout when fully filled. A partially grouted wall may fill only every fourth core; check the structural drawings rather than filling everything.
| Symbol | Meaning |
|---|---|
| A | Wall area in square feet. |
| n | Blocks per square foot. |
| V | Grout volume. |
200 ÷ 0.888 = 225 blocks; at 0.2 cu ft each that is 45 cu ft, or 1.67 cubic yards.
Continue with the Cement Calculator, Concrete Calculator, Concrete Column Calculator, or the Concrete Stairs Calculator — or browse more cement & concrete and all construction calculators.
No. Most residential walls are partially grouted at corners and around openings; fully grouted walls are used for retaining and shear walls.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026