Inputs
ft
Joint Segments
| Label | Length (ft) | Joint Width (in) | Recommended Size | Actions |
|---|
Results
Total Length
0.00 ft
Total with Waste
0.00 ft
Coils Required
0
Waste Applied
0%
Size Distribution
| Backer Rod Size | Assigned Length |
|---|---|
| No data yet. | |
Example Data
| Label | Length (ft) | Joint Width (in) | Recommended Rod (in) |
|---|---|---|---|
| Facade vertical joints | 50 | 0.375 | 0.50 |
| Horizontal control joints | 80 | 0.500 | 0.63 |
| Window perimeters | 120 | 0.250 | 0.38 |
| Door perimeters | 40 | 0.375 | 0.50 |
Formula Used
- Total joint length = sum of all segment lengths.
- Recommended rod diameter ≈ 1.25 × joint width (aiming for ~25% compression). Rounded up to next available size.
- Total with waste = total joint length × (1 + waste% / 100).
- Coils required = ceil( total with waste ÷ coil length ).
How to Use
- Select your unit system and set the coil length.
- Enter each joint segment with its label, length, and joint width.
- Adjust the waste allowance to cover offcuts, overlaps, and mistakes.
- Click Calculate to compute totals, distribution, and coils.
- Review recommended sizes and group ordering by size buckets.
- Use Download PDF or Download CSV to export.
- Switch units anytime; lengths and widths convert automatically.
FAQs
It equals the sum of all joint segment lengths. The rod follows the joint path, so length tracks joint run length. Add a waste allowance for offcuts and splices.
A common rule is selecting a diameter about 25% larger than the joint width to ensure compression. This tool rounds up to the next standard size.
Depth influences sealant volume but not rod length. Rod length depends on the linear run of joints, not depth.
Yes. Toggle imperial or metric and the calculator converts existing lengths and widths automatically, preserving your entries.
Typical allowances range from 5–10% depending on site complexity, joint accessibility, and crew experience. Increase it for many short segments and terminations.
Each row’s width is multiplied by 1.25 to target compression, then rounded up to the next standard diameter. The table groups total lengths by that rounded size.
Yes. Enter your coil length to estimate the number of coils required after waste. Use the distribution to split orders by size.
This tool is for planning purposes. Verify sizes against project specifications.