Adhesive fills the gap around the rod — the ring between the rod and the drilled hole, down the embedment depth. This works that volume out per anchor, adds an allowance for overfilling the hole, totals it across your count, and turns it into cartridges.
Read this first. This estimates material only — roughly how much epoxy to buy. It is not a structural design. The right hole diameter, embedment depth, edge distance, spacing, and load capacity come from the adhesive manufacturer’s printed instructions (MPII / ESR report) and your engineer. Always fill the hole from the bottom up and follow the cure/temperature notes on the product.
The per-anchor figure is the bare ring of epoxy around the rod (rod removed from the hole volume). The total adds your overfill allowance across every anchor, then rounds up to whole cartridges — keep a spare on hand for blow-outs and partial cartridges.
Epoxy only fills the annular gap — the ring between the rod and the hole wall — because the rod itself takes up the center. So the volume per anchor is the hole volume minus the rod: V = π/4 × (Dhole2 − drod2) × embedment. A bigger bit (more oversize) means a wider ring and more epoxy; a deeper embedment means more of it.
In the field you fill the hole part-way from the bottom, then twist the rod in — which drives epoxy up the gap and some out the top. That’s why the overfill allowance is there; the bare gap volume is the floor, not the real-world number. Cold concrete, wide or rough-drilled holes, and overhead work all push usage higher.
Choosing or setting anchors? See the guide to concrete anchors, or send us the job and we’ll spec the adhesive and quantity with you.
