Non-Shrink Grout Volume Under a Base Plate
Non-shrink grout under a column base plate - the bed volume.
Example
You enter
- Base plate length (in) 18
- Base plate width (in) 18
- Leave-out under the plate (in²: sleeves or a grout hole; the column sits ON the plate and takes none) 0
- Grout bed thickness (in) 1.5
- Bag yield (ft³) 0.45
- Waste allowance (percent) 10
You get
- Grout (in³) 486
- Grout (ft³) 0.309
- Non-shrink grout bags 1
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
ScopeLess any real leave-out (the column sits ON the plate and takes no grout), and the bags: grout = (plate length x plate width - leave-out) x thickness; bags = ceil(grout / bag yield). An 18 x 18 in plate on a 1.5 in grout bed is 486 in^3 - 1 bag with waste; a big 24 x 24 in plate at 2 in takes 2. Plate area and bed thickness both drive it. Distinct from pipe-casing annular grout.
Formula or tablegrout_in3 = (plate_length_in x plate_width_in - column_area_in2) x grout_thickness_in, where column_area_in2 is only a real leave-out (default 0: the column sits on the plate); grout_ft3 = grout_in3 / 1728 x (1 + waste_pct/100); bags = ceil(grout_ft3 / bag_yield_ft3).
Source and editionBase-plate grout-volume identity by name (net plate area x bed thickness, plus waste; bags over the bag yield); first-principles volume arithmetic.
Free accessThe grout-volume geometry is public first-principles; the bag yield comes from the product's coverage.
What governsEstimate. AHJ and licensed professional govern.
API field namesplate_length_in, plate_width_in, column_area_in2, grout_thickness_in, bag_yield_ft3, waste_pct, grout_in3, grout_ft3, bags
- Net area the plate footprint minus any real leave-out under it (the column steel sits on top and takes none)steel drawings
- Bag yield the product's per-bag yield in ft^3 (~0.45 ft^3 typical for non-shrink grout)grout manufacturer