InterNACHI Stucco/EIFS Inspector cheat sheet

Three-coat portland cement stucco scratch coat is typically 3/8 inch, brown coat 3/8 inch, and finish coat about 1/8 inch, for a nominal total of 7/8 inch over the substrate.

One-coat (fiber-reinforced) stucco is applied at a nominal 3/8 to 1/2 inch thickness in a single pass over a solid backing or lath; it is not a three-coat substitute where a drainage plane is required.

Metal lath for stucco is typically 2.5 lb/yd² self-furred or 3.4 lb/yd² flat; laps are minimum 1/2 inch at sides and 1 inch at ends, and lath must be furred at least 1/4 inch off the sheathing.

Weep screed is required at the base of stucco walls above framed floors and at the foundation; the screed's bottom flange must sit at or below the plate line with the weep holes unobstructed.

Control joints (keyed or surface) are spaced roughly 10 to 15 feet in each direction and at changes in substrate, corners, and penetrations; they must not be confused with expansion joints.

Casing bead is used at terminations and penetrations; corner aid (corner bead) reinforces external corners; both must be fastened through lath without crushing the furring.

Stucco over wood-based sheathing requires a water-resistive barrier with at least two layers (typically #15 felt or equivalent) where code or manufacturer requires, lapped shingle-fashion.

Curing is by moist curing or fogging for the scratch and brown coats; rapid drying causes map cracking and reduced strength, so hot, windy, or freezing conditions alter the schedule.

Barrier EIFS relies on the face seal of the lamina (base coat plus finish) to stop water; it has no cavity or drainage plane, so any breach admits water behind the insulation.

Drainage (water-managed) EIFS adds a drainage plane, a drainage cavity via notched or grooved insulation, and weep or drainage tracks at the base to discharge water.

Typical EIFS lamina: adhesive or mechanically fastened EPS insulation (often 1 to 4 inches), reinforced base coat with alkali-resistant fiberglass mesh, and a textured finish coat.

Mesh must be embedded in the base coat with laps of at least 2.5 inches (often 4 inches for extra protection), and backwrapping is required at terminations and around openings.

EPS insulation board joints must be tight and offset from substrate joints; gaps wider than about 1/16 inch are filled, and board thickness tolerances affect lamina flatness.

EIFS is not a structural material; impact resistance depends on mesh weight and base coat thickness, and high-traffic areas may require heavier mesh or reinforcing.

Sealant joints at EIFS penetrations, windows, and terminations must be designed as a drained or sealed interface per the system manufacturer; sealant alone is not a substitute for flashing.

EIFS over OSB or other moisture-sensitive sheathing requires the sheathing to be protected by the WRB and, in drainage systems, a defined path for water to exit at the base.

Water enters stucco and EIFS at four common paths: penetrations, terminations, horizontal surfaces and ledges, and cracks or failed sealant; each needs a flashing or drainage remedy.

In barrier EIFS, elevated moisture in sheathing is detected with a pin or pinless moisture meter; readings above roughly 16 to 20 percent wood moisture content warrant further investigation and possible destructive testing.

Stucco applied directly over wood sheathing without a WRB is a known moisture risk; the absence of a drainage plane means incidental water is trapped between stucco and sheathing.

Roof-to-wall intersections, deck ledges, and chimney chases concentrate water; kick-out flashing is required where a roof terminates against a wall to divert water away from the stucco.

Window and door openings must have sill pan flashing or a sloped sill with a back dam; relying on sealant at the sill is a common failure.

Negative grading and hardscape that slope toward the wall keep the stucco base wet; the weep screed must be at least 4 inches above grade or 2 inches above paved surfaces per common code practice.

Cracks wider than about 1/16 inch, especially diagonal cracks at corners of openings, suggest movement or moisture-related distress and should be probed and mapped.

Moisture intrusion often shows as efflorescence, staining, soft or swollen sheathing, or interior finish damage; these are indicators, not proof, so confirm with moisture readings.

Flashing must be installed shingle-fashion: upper layers overlap lower layers, and the WRB laps over the flashing flange at the top of an opening.

At windows and doors, the sill flashing is installed first, then jamb flashing, then head flashing; head flashing must include a drip edge and end dams.

Kick-out flashing is required at the bottom of any roof-to-wall intersection and must extend at least 4 inches above the roof and project beyond the wall face.

Weep screed and drainage tracks are the base-of-wall exit points; they must be clear of stucco, sealant, soil, and paving, and must be inspected before finish coats.

Penetrations (hose bibs, dryer vents, electrical boxes) need a sealed flange or flashing that laps the WRB above and is sealed at the face; sealant alone is not flashing.

Chimney chases, bay windows, and other bump-outs need a cricket or diverter at the top and base flashing with a drainage path at the bottom.

Deck ledger boards at stucco walls must be flashed with a Z-flashing or spacer that keeps water off the stucco and allows drainage; direct ledger contact with stucco traps water.

At roof-to-wall, the wall WRB must lap over the roof flashing, and the stucco must terminate above the roof with a weep screed or casing bead and sealant joint.

Pre-inspection: obtain drawings, specifications, and the stucco or EIFS manufacturer's installation instructions; identify the system (three-coat, one-coat, barrier EIFS, drainage EIFS) before judging compliance.

Inspect in sequence: substrate and WRB, lath and furring, flashing and weep screed, then coats and finish; concealed items must be verified before they are covered.

Use a moisture meter on a grid across suspect walls and record readings with location, date, and meter mode; confirm elevated readings with a second method or probe.

Probe or remove a small section only with owner permission; document the location, the exposed layers, and the presence or absence of WRB and flashing.

Check thickness by probing finish coats at representative locations or by measuring at a core; record the number of coats where visible at terminations and penetrations.

Photograph defects with a scale reference and note orientation, elevation, and weather exposure; a defect is not reportable without a location that another person can find.

Report format: describe the observed condition, the standard or manufacturer requirement it departs from, the likely consequence, and the recommended specialist evaluation; avoid stating a cause as fact when it is inferred.

Map cracking (fine, random, interconnected cracks) is usually shrinkage-related and cosmetic unless it admits water; note it as a maintenance item rather than structural failure.

Diagonal cracks radiating from opening corners indicate stress concentration or movement and warrant evaluation; horizontal cracks at floor lines can indicate framing or sheathing movement.

Delamination is detected by tapping with a sounding tool; a hollow sound indicates the lamina or stucco has separated from the substrate and is a reportable defect.

Efflorescence is a white salt deposit that indicates water movement through the assembly; it is evidence of moisture, not the cause, and should trigger a moisture investigation.

Terminations without casing bead, backwrapping, or sealant joints leave the lamina edge unprotected and are reportable as an installation defect.

Missing weep screed, buried weep screed, or stucco extending below grade are reportable drainage defects; note the clearance measurement in the report.

Sealant failures (adhesion loss, cracking, gaps) at windows and penetrations are reportable as maintenance or installation defects depending on age and cause.

Report language should distinguish observed condition from opinion: state what was seen and measured, cite the applicable requirement, and recommend further evaluation by a qualified stucco or EIFS contractor or engineer.