How much stucco do I need?
Stucco is estimated from the wall area, then split between the thick base coats and the thin finish coat:
Wall area = length × height − openings, then base-coat bags = area × 2 ÷ 25, and finish-coat bags = area ÷ 70
The two base coats (scratch and brown) each go on about 3/8 inch thick, where an 80-lb bag covers ~25 sq ft — so you need that coverage twice. The finish coat is only ~1/8 inch, so a finish bag stretches to ~70 sq ft. We round each up to whole bags.
The three coats
| Coat | Thickness | Coverage (80-lb bag) |
|---|---|---|
| Scratch (1st base) | ~3/8 in | ~25 sq ft |
| Brown (2nd base) | ~3/8 in | ~25 sq ft |
| Finish (color) | ~1/8 in | ~70 sq ft |
Three-coat, one-coat, or EIFS?
- Traditional three-coat. Scratch + brown + finish over lath, ~7/8 in total — the most durable and the default for cement stucco.
- One-coat system. A fiber-reinforced base in a single ~3/8–1/2 in pass over a foam or lath substrate, then a finish coat — faster; follow its own coverage.
- EIFS ("synthetic stucco"). Foam board plus a polymer base and acrylic finish. It looks similar but is a different system with its own moisture detailing — not what this calculator estimates.
What you need besides the stucco
Over wood framing, the assembly matters as much as the mix: two layers of weather-resistant building paper (WRB), metal lath for the stucco to grip, a weep screed at the base to drain trapped water, and casing bead and control joints to manage cracking. Over solid masonry you can stucco directly, usually with a bonding agent.
How much does stucco cost?
Stucco mix runs about $9–$20 per 80-lb bag (base and finish are different products), plus lath, paper, and trim. Installed by a pro, three-coat stucco typically runs several dollars per square foot — the labor and lath, not the mix, drive most of the cost.
Good to know
- Lath over wood. Frame walls need two layers of building paper and metal lath; masonry can take stucco directly with a bonding agent.
- Add a weep screed. At the base of frame walls it lets trapped water escape — required by code in most areas.
- Keep it damp. Moist-cure the base coats so they don't dry too fast and crack; avoid stucco in freezing or scorching weather.
- One-coat systems exist. Fiber-reinforced one-coat stucco covers less per bag but saves a step — follow its own coverage.