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 |
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.