Enter the wall area and the thickness of base coat. The calculator converts the bag coverage on the data sheet into a volume per bag and works out how many bags of scratch and brown base coat to buy.
Stucco formula
Yield per bag (cu ft) = coverage at 3/8 in × 0.375 ÷ 12 Volume (cu ft) = area × thickness (in) ÷ 12 × (1 + waste %) Bags = volume ÷ yield, rounded up
The QUIKRETE Scratch and Brown Base Coat data sheet gives 20–24 sq ft per 80 lb bag at 3/8 in, 15–18 sq ft at 1/2 in and 10–12 sq ft at 3/4 in. The calculator uses the 3/8 in figure and scales it to your thickness.
Worked example: 400 sq ft at 3/8 in
- Yield per bag: 22 × 0.375 ÷ 12 = 0.688 cu ft.
- Volume with 10% waste: 400 × 0.375 ÷ 12 × 1.10 = 13.75 cu ft.
- Bags: 20.
Coats in a traditional system
A traditional three-coat system has a scratch coat and a brown coat, which together make up the base, then a finish coat. Measure the base coat thickness from your plans; the finish coat is a different product and is estimated from its own bag coverage. Lath, corner bead and weep screed are extra.
Questions
How many bags of stucco for 100 sq ft?
About 5 bags at 3/8 in, or 10 bags for a 3/4 in scratch-and-brown base.
Can I subtract windows and doors?
Yes, subtract large openings; small ones can be left in to cover waste.
Does this include the finish coat?
No. Estimate the finish coat separately from its bag.
Sources
- QUIKRETE Scratch and Brown Base Coat Stucco (No. 1139) data sheet, QUIKRETE.
Used for: Coverage per 80 lb bag of 20–24 sq ft at 3/8 in, 15–18 at 1/2 in and 10–12 at 3/4 in.