Sheet M-204 · Material chapter D · Moisture section
Stucco & EIFS: the material is rarely the problem — the water path is
Conventional stucco is a three-coat cement plaster over lath: scratch, brown, and finish. EIFS is a synthetic system — insulation board, base coat, mesh, finish — that looks similar and behaves differently. Atlanta's humid climate punishes both when water enters and cannot drain.
How failures actually happen
Entry
Water arrives at window heads, deck ledgers, roof-wall junctions, and cracked or unflashed penetrations — rarely through the field of the wall.
Trapping
Barrier-style EIFS (the 1990s pattern) and stucco over a backwards-lapped barrier give water no drainage path. Sheathing stays wet for weeks at a time.
Quiet damage
Rot and mould grow behind an intact-looking surface. The first visible sign is often a stain, a soft spot at a window corner, or a musty interior wall.
Diagnosis before demolition
Moisture probes and selective openings, mapped on the elevation, tell you whether you face a detailing repair or a section rebuild. Anyone quoting a full re-coat without probing is guessing with your money.
Living with stucco in Atlanta
Keep the weep screed clear at the base, maintain sealant joints at dissimilar materials, wash mildew rather than pressure-blasting it into the coats, and repaint with breathable, stucco-appropriate coatings on the cycle the manufacturer states. Conventional stucco installed: $7.00–$11.00 per sq ft — EIFS pricing varies too widely by system to ledger honestly here, so it is quoted only after inspection. Interfaces with new siding — a stucco gable over a lap field, for example — need a drained transition flashing, detailed on the job sequence page.