Input details
Example data table
| Crack length | Width | Depth | Count | Waste | Density | Mix ratio | Final volume | Total mass | Resin | Hardener |
|---|---|---|---|---|---|---|---|---|---|---|
| 10 m | 0.5 mm | 20 mm | 1 | 15% | 1.10 kg/L | 2:1 | 0.115 L | 126.5 g | 84.3 g | 42.2 g |
Formula used
-
Crack volume
Convert dimensions to meters first.
Vcrack(m³) = L × W × D × N
Vcrack(L) = Vcrack(m³) × 1000 -
Surface seal volume (optional)
Vseal(m³) = Lseal × B × T
Vseal(L) = Vseal(m³) × 1000 -
Waste / overfill
Vfinal(L) = (Vcrack + Vseal) × (1 + waste%/100) -
Mass and mix split
Mtotal(kg) = Vfinal(L) × density(kg/L)
Mresin = Mtotal × R/(R+H)
Mhardener = Mtotal × H/(R+H)
How to use this calculator
- Measure crack length along the repair path.
- Estimate average crack width and effective depth.
- Enter crack count for repeated or segmented cracks.
- Add wastage to cover leakage and mixing loss.
- Set epoxy density and your resin-to-hardener ratio.
- Click Calculate, then download CSV or PDF if needed.
Input definition and repair scope
Use this calculator to estimate two‑part epoxy required for crack injection and optional surface sealing on concrete or masonry. Define the scope: crack length, average width, and effective depth to be filled. For repeated cracks of similar size, enter crack count to scale quantity. Choose units carefully so field measurements match the form, and record where each dimension was taken.
Geometry conversion and volume calculation
The core quantity is geometric volume. Length is converted to meters, while width and depth convert from millimeters or inches. Volume per crack equals length × width × depth. The calculator multiplies by crack count and converts cubic meters to liters for batching. If you add a surface seal bead, its volume is seal length × bead width × bead thickness, then added to the crack volume.
Density and mix ratio planning
Epoxy products are specified by density and mix ratio. Density converts final liters into mass, supporting procurement by kilograms or grams. Enter the manufacturer density when available; otherwise, a typical range near 1.05–1.20 kg/L works for many systems. The resin and hardener split uses parts: resin mass = total mass × R/(R+H), hardener mass = total mass × H/(R+H).
Waste, overfill, and field variability
Real repairs consume more material than ideal geometry predicts. Add a waste percentage to cover leakage at ports, mixing residue, and minor overfill. Higher waste is common for rough substrates or long injection lines with multiple fittings. If width varies, run scenarios for narrow, typical, and worst‑case values. Summing scenarios gives a safer purchase quantity while limiting leftovers.
Documentation, checks, and reporting
Before ordering, sanity‑check the inputs: confirm units, verify depth suits the injection method, and confirm bead dimensions if sealing is included. Review crack volume, seal volume, base volume, and final volume with waste. Download the CSV for takeoffs and the PDF for site records, approvals, or coordination. Recalculate after mock‑up testing to tune the waste factor. For ordering, compare the final mass to kit sizes, round up to whole units, and keep one small contingency kit for unexpected voids during cooler weather.
FAQs
What crack types suit epoxy injection?
Epoxy injection is commonly used for structural cracks in concrete where restoring continuity matters. Non‑structural or moving cracks may need flexible sealants or routing and sealing instead.
Should I measure maximum or average width?
Use an average width over the repair length. If width varies a lot, run separate cases for typical and worst‑case widths, then sum the quantities.
Why does density matter in the results?
Volume estimates show how much space to fill, while density converts that volume to mass. Many suppliers sell kits by weight, so mass helps ordering and batching.
How do I choose a waste percentage?
Start with 10–15% for controlled injections. Increase it for porous substrates, many ports, or difficult access. Field trials and mock‑ups help refine the value.
Does the mix ratio split represent volume or weight?
This calculator splits total mass by parts. Use it when the manufacturer specifies a parts ratio suitable for weight-based mixing. Always follow product instructions if they differ.
Can I use the surface seal option for routing grooves?
Yes. Enter the seal length and an equivalent bead width and thickness that represent the groove fill. It adds that sealing material to the overall requirement.