Epoxy calculator for rebar dowels
Adhesive volume is the hole minus the bar. Enter bar size, hole diameter, embedment and count. The calculator returns ounces per hole, total adhesive with waste, and how many cartridges to order.
- Annular volume per hole
- Waste allowance
- Cartridge count
- Cost per dowel
1 · Holes
2 · Adhesive
Bar diameters per ASTM A615. 1 US fl oz = 1.80469 in³; 1 fl oz = 29.5735 mL. Hole diameter must follow the adhesive manufacturer's published installation instructions for the bar size; waste % is an editable assumption. This estimates material only; it is not an anchor design.
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Copy these results, then add your approved sample files in the trial brief.
Why the annulus matters
Adhesive anchoring systems fill the gap between the bar and the drilled hole. The volume per hole is the cylinder of the hole minus the cylinder of the bar, times the embedment depth. Because the gap is thin, small changes in hole size change the adhesive volume a lot. That is why the hole diameter should come from the adhesive manufacturer's installation instructions for that bar size, not from a rule of thumb.
- Bar diameter. Nominal per ASTM A615 (#4 0.500 in, #5 0.625 in, #6 0.750 in). Deformations take up a little volume, which the waste allowance covers.
- Hole diameter. From the product's installation table. Typical holes are 1/8 in or so larger than the bar.
- Embedment. From the drawings or the anchorage design. Deeper embedment raises both drilling and adhesive cost.
- Waste. Mixing nozzle purge, overfill and cleanup. 10 to 20% is a common editable assumption.
From hole to cartridge
| Bar | Bar dia. (in) | Example hole (in) | Volume per in of depth (in³) |
|---|---|---|---|
| #4 | 0.500 | 0.625 | 0.110 |
| #5 | 0.625 | 0.750 | 0.135 |
| #6 | 0.750 | 0.875 | 0.160 |
| #8 | 1.000 | 1.125 | 0.209 |
Example holes are illustrative only. Use the hole diameter in your adhesive's installation instructions. 1 US fl oz = 1.805 in³.
Adhesive is the small part
On most doweling scopes the adhesive is a minor cost next to drilling, hole cleaning, setting, inspection and the access needed to reach each location. Count dowels by location type (slab edge, wall face, overhead) because production rates differ a lot between them. The calculator handles material; carry labor per dowel from your own history.
The harder problem is the count. Dowels show up in plan keynotes, typical details and sections, and a single note like "#5 dowels at 12 in o.c. at all new-to-existing slab joints" has to be turned into a length and a count. RenderDraw's AI takeoff proposes those quantities with the source attached and holds unclear notes open for your estimator.
Rebar and concrete quantities you can trace back to the sheet.
RenderDraw's AI takeoff proposes counts, lengths and areas from structural drawings and schedules, keeps the source on every row, and holds uncertain items for estimator review.
- Footing, slab and wall schedules read in context. Quantities stay linked to the schedule and plan that produced them.
- Review queue sorted by confidence. Work the questionable items first.
- Addenda through the same review. Send the changed sheets back through takeoff and estimator review.
- Estimator approval before pricing. Laps, waste, accessories and labor stay with you.
Send one structural set
Include the foundation plan and schedules. Files stay private while RenderDraw assesses the request. No obligation.
RenderDraw does not publish accuracy percentages or time-saved claims. Test it on your own plan set.
Questions estimators ask.
How much epoxy do I need for a rebar dowel?
Compute the hole volume minus the bar volume over the embedment depth. A #5 bar in a 3/4 in hole at 6 in embedment needs about 0.81 in³, roughly 0.45 fl oz before waste.
How many dowels does a cartridge fill?
Divide the cartridge volume (after nozzle waste) by the volume per hole. The calculator does this for the cartridge size you enter.
What hole size should I drill for #5 rebar?
Use the size in the adhesive manufacturer's installation instructions for that product and bar size.
Does the calculator include drilling labor?
No. It estimates adhesive material only. Drilling and setting labor depend heavily on access and location type.
Can RenderDraw count dowels from drawings?
RenderDraw's AI takeoff proposes quantities from plans, keynotes and details with sources and review flags. Get a free sample takeoff.
Dowel counts hide in details and keynotes.
Send a set. RenderDraw proposes dowel locations and counts from plans and details with their source, and flags notes it could not tie to a count.
- Upload the plans, specs and schedules, plus an addendum if you have one.
- RenderDraw reviews the set and the scope you want tested.
- We follow up with extracted quantities, flagged items and next steps.