Concrete Overlay / Resurfacing Calculator
Short answer: a 10 × 10 ft overlay at 1/4 inch needs 6 bags of Sakrete Flo-Coat (40 lb) — 2.08 cu ft of resurfacer. Pick your product below.
Calculate your overlay
How the calculation works
Volume = area × thickness (cubic feet). Coverage per bag at your thickness is a calculated estimate, scaled from the product's published coverage point: coverage scales inversely with thickness, so doubling the thickness halves the area one bag covers. Bags are rounded up to whole bags. Resurfacer is ordered by the bag, so this page reports cubic feet and bags — not cubic yards.
Worked example: 10 × 10 ft at 1/4 in, Sakrete Flo-Coat 40-lb → 100 sq ft, 2.08 cu ft. Coverage 18 sq ft per bag at 1/4 in → 100 ÷ 18 = 5.56 → 6 bags. Yield check: 2.08 ÷ 0.4 = 5.21 → 6 bags. The manufacturer's own bag table agrees: 100 sq ft at 1/4 in = 6 bags.
Published coverage used on this page
| Product | Published coverage | Bag yield |
|---|---|---|
| QUIKRETE Concrete Resurfacer #1131-40, 40 lb | about 17 sq ft at 1/4 in | not published |
| QUIKRETE Re-Cap #1131-47, 40 lb | about 17 sq ft at 1/4 in; about 65 sq ft at 1/16 in | not published |
| Sakrete Flo-Coat, 40 lb | 18 sq ft at 1/4 in; 72 sq ft at 1/16 in | 0.4 cu ft |
| Sakrete Flo-Coat, 20 lb | 9 sq ft at 1/4 in; 36 sq ft at 1/16 in | 0.2 cu ft |
| CTS Rapid Set Concrete Resurfacer, 50 lb | about 96 sq ft at 1/16 in only | 0.5 cu ft |
| ARDEX CD Concrete Dressing, 40 lb | up to 120 sq ft at 1/16 in; up to 60 sq ft at 1/8 in | not published |
| Tenon Concrete Resurfacer, 50 lb | 100 / 50 / 25 / 12.5 sq ft at 1/16 / 1/8 / 1/4 / 1/2 in | not published |
Thickness range: 1/16 to 1/2 in (feather edge to 1/2 in on several products). CTS Rapid Set is typically 1/16–1/4 in, up to 1/2 in in smaller areas only; ARDEX CD is typically 1/16–1/8 in, up to 1/2 in in small, well-defined areas only. No 1/4-in point is published for CTS or ARDEX, so their calculations here are scaled from the published 1/16-in point and labelled as estimates.
Surface preparation: prepare the surface exactly as the product datasheet directs — the products checked here do not all agree. QUIKRETE, Sakrete and Tenon are applied to a damp (saturated-surface-dry) surface; CTS Rapid Set and ARDEX CD are applied to a dry surface. Never assume one rule for all products. The surface must be clean and sound before any resurfacer goes down.
How to use this calculator
- Enter your measurements in the calculator above, in the units shown.
- Check the inputs against what you measured — depth is the number most often entered wrong.
- Press Calculate, then use the order amount (with waste, where shown) when you buy or order.
Frequently asked questions
How many bags of resurfacer do I need?
It depends on the area, the thickness and the product: a 10 × 10 ft overlay at 1/4 inch needs 6 bags of Sakrete Flo-Coat (40 lb), covering 18 sq ft per bag at that thickness — 2.08 cu ft of resurfacer.
How thick can a concrete overlay be?
Most resurfacer products work from 1/16 inch to 1/2 inch. The thicker end of that range is for small, well-defined areas only on some products — check the datasheet for the product you are using.
Do I need to prepare the old concrete first?
Yes. The surface must be clean and sound, and existing control joints and cracks must be honoured. Whether the surface should be damp or dry depends on the product — check its datasheet; the products on this page do not all agree.
Why does this calculator ask which product I am using?
Because coverage per bag is product-specific and there is no generic default. Each product's published coverage is used for its own calculation, and a custom option lets you enter another product's published coverage.