Vertical Concrete Mix Calculator
Calculate mix materials for vertical overlays, carved rock, and sculpted concrete facades including lath, polymer, and fibers.
About this calculator
Pre-mix Bags scales with Surface Area, Thickness, and Waste Factor -- all three are true continuous drivers here, including Waste Factor, which is a direct multiplier on every material quantity (raising it from 0% to 30% moves Pre-mix Bags from 15 to 19 and Pre-mix Cost from about $895 to $1,088 at the same 100 sq ft area). Application Mode behaves differently from what its three-way label suggests: it never touches Pre-mix Bags at all (17 bags at every mode, 1 through 3), and while it does add a Scratch Coat once you cross from Mode 1 (thin overlay) into Mode 2 or 3, Mode 2 (standard sculpted) and Mode 3 (heavy carved rock/waterfall) produce IDENTICAL results for every output -- the same 4 scratch-coat bags, the same roughly $991 pre-mix cost.
The calculator's only real distinction is a single on/off threshold at Mode >= 2, not three genuinely different material intensities, so choosing Mode 2 versus Mode 3 makes no numeric difference here -- only Thickness, Area, and Waste Factor change the material totals once you're past that threshold. Site-mix figures (cement, sand, polymer, fiber, water) never reference Application Mode at all; they respond only to Area, Thickness, and Waste Factor.
Inputs
Results
Pre-mix bags (50 lb)
17
How to Use This Calculator
- Enter the vertical or overhead surface area in sq ft and the application thickness in inches.
- Select the application mode: 1=thin overlay (1/8–1/4 in), 2=standard sculpted (1/2–1 in), 3=heavy carved rock or waterfall (1–3 in).
- Set a waste factor of 15% for vertical work — higher than flatwork due to sagging and overspray.
- For pre-mix approach, use Pre-mix Bags (50 lb) and Metal Lath Sheets for your material order.
- For site batching, refer to Cement (lbs), Sand (lbs), Acrylic Polymer (gal), and Polypropylene Fiber (lbs).
- Compare Pre-mix Material Cost versus Site-mix Material Cost to choose the most economical approach.
How the result changes with Surface area (sq ft)
| Surface area (sq ft) | Pre-mix bags (50 lb) |
|---|---|
| 50 | 9 |
| 75 | 13 |
| 150 | 25 |
| 250 | 42 |
What each input means
- Surface area (sq ft)
- Vertical or overhead surface area to cover.
- Application thickness (inches)
- Thin overlay: 1/8-1/4". Standard sculpt: 1/2-1". Heavy carved rock: 1-3".
- Application mode (1-3)
- 1 = thin overlay, 2 = standard sculpted, 3 = heavy carved rock/waterfall.
- Waste factor (%)
- Vertical work has higher waste. 15% standard; complex shapes may need 20-25%.
What each result means
- Pre-mix bags (50 lb)
- Bags of pre-mixed vertical concrete overlay product.
- Scratch coat bags
- Additional bags for scratch/bond coat on heavy applications.
- Total material weight (lbs)
- Total dry material weight (useful for scaffolding load planning).
- Metal lath sheets
- 2.5-lb expanded metal lath sheets (2.33' x 8') including overlap.
- Cement - site mix (lbs)
- Portland cement for site-batched mix alternative.
- Sand - site mix (lbs)
- Fine 30-mesh sand for site-batched mix.
- Acrylic polymer (gal)
- Acrylic polymer modifier for adhesion and flexibility.
- Polypropylene fiber (lbs)
- Short fibers for crack resistance.
- Mixing water (gal)
- Water needed (stiffer than flatwork mixes).
- Pigment (lbs, 3% dose)
- Iron oxide pigment at 3% of cement weight.
- Pre-mix material cost ($)
- Cost using bagged pre-mix product plus lath.
- Site-mix material cost ($)
- Cost of raw ingredients for site batching (no lath).
- Material cost / sq ft ($)
- Pre-mix material cost per square foot.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersSurface area (sq ft) = 100, Application thickness (inches) = 0.5, Application mode (1-3) = 2, Waste factor (%) = 15 = 4 input(s) provided
- Calculate Pre-mix bagsPre-mix bags = ceil(bagsNeeded)17 = 17
- Calculate Scratch coat bagsScratch coat bags = needsScratchCoat ? ceil((areaSqFt / (baseCoveragePerBagAt025 * (0.25 / 0.125)...4 = 4
- Calculate Total material weightTotal material weight = bagsNeeded * 50821 = 821
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Does choosing Mode 3 (heavy carved rock) instead of Mode 2 (standard sculpted) change the material quantities?
No -- despite the labels suggesting three different intensities, this calculator only distinguishes Mode 1 from Modes 2 and 3. Modes 2 and 3 produce identical numbers for every output, including Scratch Coat Bags (4) and Pre-mix Cost (about $991 at the default 100 sq ft area); only crossing from Mode 1 into Mode 2 or 3 changes anything.
Does the Waste Factor really matter, or is it just a small buffer?
It's a direct multiplier on every material quantity this calculator outputs -- bags, cement, sand, polymer, fiber, and both cost figures all scale by (1 + Waste Factor / 100). At the default 100 sq ft area, raising Waste Factor from 0% to 30% moves Pre-mix Bags from 15 to 19 and Pre-mix Cost from about $895 to $1,088.
Does Application Mode affect how many bags of pre-mix I need to order?
No. Pre-mix Bags is calculated purely from Surface Area, Application Thickness, and Waste Factor -- Application Mode never enters that formula at all, staying at 17 bags across Modes 1, 2, and 3 at this calculator's defaults. Application Mode only controls whether a Scratch Coat is added.
Do Application Mode and Waste Factor affect the site-mix cement and sand quantities?
Waste Factor does -- it's a direct multiplier on Cement, Sand, Polymer, and Fiber, same as the pre-mix figures. Application Mode does not; the site-mix recipe responds only to Surface Area, Application Thickness, and Waste Factor, regardless of which application mode you select.
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