CSLB General Building (B)Finishes and Building EnvelopeEasy
A stucco contractor is applying traditional three-coat (hard-coat) stucco over metal lath on a new wood-framed exterior wall. What is the correct sequence of the three coats?
- AFinish coat, brown coat, scratch coat
- BScratch coat, finish coat, brown coat
- CBrown coat, finish coat, scratch coat
- DScratch coat, brown coat, finish coat
Show answer & explanationAnswer & explanation
Correct answer: D. Scratch coat, brown coat, finish coat
Three-coat stucco is applied in the order scratch, brown, then finish. The scratch coat bonds to the lath and is scored to key the brown coat, the brown coat provides a flat, true surface, and the finish coat provides the final texture and color.
Why the other options are wrong
- A. Reverses the required order; finish cannot go on bare lath.
- B. Skips the brown coat entirely, leaving no base for the finish coat.
- C. Finish coat cannot be applied before the brown coat is in place.
Three-Coat Stucco
Traditional cement plaster system applied in three layers over lath: scratch, brown, and finish coats, each serving a distinct structural or aesthetic purpose.
- Scratch coat is scored horizontally to key the brown coat
- Brown coat provides a flat, true plane for finish application
- Finish coat provides color and texture and is the thinnest layer
Memory trick: 'Scratch, Brown, Finish' — like sanding rough to smooth to polished.