Block Core Fill Calculator
Grout or concrete to fill concrete block cores, in cubic yards and 80 lb bags.
Turn these numbers into a build plan.
- 60 cores
- 3.81 cu yd fill
- $1,204 est. cost
Cut list: Block Core Fill Calculator
- Blocks in the wall360
- Cores to fill60 (12 courses)
- Fill volume3.81 cu yd
- 80 lb bags172
- [ ] Core fill grout or 80 lb premix172 bags or 3.81 cu yd
- [ ] Core fill grout, 80 lb
- [ ] Plastic sheeting
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Grout 60 block cores
Fill 60 cores in a 40 ft wall with 3.81 cubic yards of grout.
- Materials
- $1,204
- Time
- 2 days
- Level
- Intermediate
- 1
Confirm the wall design
Check reinforcing layout and permits with your building department before you pour.
- Layout confirmed
- 2
Clean the cores
Remove mortar droppings and debris from every core.
- Cores clear
- 3
Set the rebar
Place and tie any vertical bars and block cleanouts.
- Bars plumb
- Cores
- 60
- Fill
- 3.81 cu yd
- Est. cost
- $1,204
6 steps · 5 tools · 2 materials
3 more steps, the full tool list and a shopping list you can check off as you go.
Your plan is 60% built. Save it.
3/5Grout 60 block cores
Finished in 2 days · $1,204 DIY
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How to calculate concrete block core fill
A standard 16 in block has two cores. Core volume depends on block width.
- Count courses. Divide wall height in inches by 8.
- Count cores. Two per block, or only the cores on your reinforcing spacing.
- Multiply by the void. Multiply cores by courses by the volume of one core.
- Convert. Divide cubic feet by 27 for yards, or by 0.6 for 80 lb bags.
- Add waste. Add 10% for grout that runs into voids and joints.
Core fill per 100 sq ft of wall
| Block width | Void per block | Cubic yards per 100 sq ft |
|---|---|---|
| 6 in | 0.17 cu ft | 0.71 |
| 8 in | 0.26 cu ft | 1.08 |
| 10 in | 0.35 cu ft | 1.46 |
| 12 in | 0.46 cu ft | 1.92 |
Void figures are typical and vary by block. Size the wall with the masonry estimator. Structural walls need a design from an engineer or your local prescriptive code.
Frequently asked questions
How much concrete fills a block?
Should I use grout or concrete?
Do all cores need filling?
How high can I pour at once?
Why is my real number higher?
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