Estimate the concrete or grout needed to fill the cores of concrete blocks (CMU) for a wall, in bags or cubic metres.
Hollow concrete blocks (CMU) have voids or cores. Filling these with concrete or grout adds strength, especially where rebar is used or where extra structural capacity is needed. This calculator estimates the volume of fill, the number of bags and the equivalent in cubic yards.
For partially filled walls, reduce the fill percentage to match the number of cores being grouted. Add a little extra for spillage and consolidation.
A standard 215mm UK hollow block takes roughly 10 litres of fill per block when fully grouted, though this varies with the exact block design.
Not always. Many walls only have cores filled where rebar is placed or where structural design requires it. Set the fill percentage to match.
Yes. Fine grout or a small-aggregate concrete flows into block cores more easily than standard mixes. The volume needed is the same.
The calculator divides the fill volume by the yield of a 25kg bag (about 0.0166 m³) and rounds up to whole bags.
Filling cores increases the wall's strength, stiffness and resistance to lateral loads, and locks reinforcing bars in place.
Calculate how much concrete you need for slabs, footings, columns and walls in cubic yards or metres.
OpenWork out the cement, sand and aggregate (ballast) quantities for a concrete mix by volume and ratio.
OpenCalculate the concrete volume and number of bags needed for strip, pad and pier footings.
Open