EIFS Substrate Preparation & Surface Compatibility 2 — Questions and Answers
Question 1: Which of the following conditions on a metal stud-framed wall assembly is MOST critical to verify before EIFS installation?
- Stud color coating
- Sheathing panel joint gap width (Correct answer)
- Stud manufacturer's country of origin
- Metal stud gauge less than 25
Correct answer: Sheathing panel joint gap width
Sheathing panel joint gaps must not exceed manufacturer-specified tolerances because excessive gaps can cause stress concentrations leading to cracking in the EIFS finish.
Question 2: When preparing a stucco substrate to receive EIFS, what condition requires complete removal rather than simple patching?
- Hairline crazing on the surface
- Delaminated or hollow-sounding stucco (Correct answer)
- Surface weathering and chalking
- Color variation from age
Correct answer: Delaminated or hollow-sounding stucco
Delaminated stucco has failed its bond to the substrate and cannot support EIFS; it must be removed and the area recoated properly before EIFS installation.
Question 3: What is the recommended minimum drying time for new concrete before EIFS can be applied?
- 7 days
- 14 days
- 28 days (Correct answer)
- 60 days
Correct answer: 28 days
New concrete must cure for a minimum of 28 days to achieve adequate strength and allow excess moisture to dissipate before EIFS adhesive application.
Question 4: An EIFS inspector finds that OSB sheathing has been installed with the grade stamp facing outward. What is the correct action?
- Accept it as is since OSB is acceptable facing either way
- Reject it because the grade stamp side must face the framing (Correct answer)
- Apply additional primer to compensate
- Increase fastener count to compensate for improper installation
Correct answer: Reject it because the grade stamp side must face the framing
OSB must typically be installed with the grade stamp side facing the framing so the smoother, factory side faces outward to provide better adhesion for EIFS.
Question 5: Which fastener pattern is critical to verify during sheathing inspection for an EIFS substrate?
- Fasteners installed at panel centers only
- Fasteners flush or slightly below the sheathing surface without breaking the facing (Correct answer)
- Fasteners driven through the sheathing face by 1/4 inch
- Fasteners placed at 24 inches on center along edges
Correct answer: Fasteners flush or slightly below the sheathing surface without breaking the facing
Fasteners must be flush or slightly countersunk without breaking the sheathing face to maintain substrate integrity and avoid creating stress points.
Question 6: When inspecting a substrate for EIFS application, what does a 'hollow' sound when tapping indicate?
- Properly cured concrete
- Delamination or voids behind the surface (Correct answer)
- High moisture content
- Correct installation of drainage cavity
Correct answer: Delamination or voids behind the surface
A hollow sound when tapping indicates delamination or voids, meaning the substrate layer has separated from the backing and cannot support EIFS application.
Question 7: What is the maximum out-of-plane tolerance (flatness) typically required for an EIFS substrate?
- 1/8 inch in 10 feet
- 1/4 inch in 10 feet (Correct answer)
- 1/2 inch in 10 feet
- 1 inch in 10 feet
Correct answer: 1/4 inch in 10 feet
EIFS substrates must be within 1/4 inch in 10 feet of plane to ensure uniform adhesive coverage and prevent stress concentrations from bridging irregular surfaces.
EIFS Substrate Preparation & Surface Compatibility 2
Which of the following conditions on a metal stud-framed wall assembly is MOST critical to verify before EIFS installation?