Flatness and Fastener Verification Before Base Coat
You are inspecting a steel-stud EIFS wall on a two-story addition before the base coat is applied. The sheathing is exterior gypsum, and the stud spacing is 16 in. (406 mm) on center. You check flatness with a 4 ft (1.2 m) straightedge and find a 1/4 in. (6 mm) deviation over a 4 ft span in one area, and a 3/8 in. deviation in another. The fastener pattern appears to be 12 in. on center at panel edges and 16 in. in the field, but you cannot confirm the fastener type from the ground. The contractor says the deviations are within 'normal framing tolerance' and that the EIFS lamina will bridge them. The specification references the manufacturer's flatness tolerance and requires the correct fastener type and spacing.
1. How do you evaluate the two flatness deviations against the manufacturer's tolerance?
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The deviations must be measured against the manufacturer's published flatness tolerance, not against generic framing tolerance. A 1/4 in. deviation over 4 ft may or may not comply depending on the system's stated tolerance; a 3/8 in. deviation over the same span is more likely to exceed it. The inspector should obtain the manufacturer's tolerance, record each measurement with its location and the straightedge length used, and compare. The claim that the lamina will 'bridge' the deviation is not sufficient: excessive deviation can cause the base coat and finish to crack, telegraph, or bond poorly, and it can affect drainage. If either deviation exceeds the tolerance, require correction, such as shimming or adjusting the framing or sheathing, before the WRB and base coat are installed. Document both measurements and the disposition separately so the record shows which condition was accepted and which was corrected.
2. What do you do about the unverified fastener type and spacing?
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Fastener verification cannot be left to assumption. The specification requires a specific fastener type and spacing, and the inspector must confirm both. Since the type cannot be confirmed from the ground, require access, such as a lift or ladder, or require the contractor to expose a representative area, and check the fastener head type, length, and spacing against the manufacturer's instructions and the specification. Record the actual edge and field spacing and compare them to the required pattern. If the fastener type or spacing is wrong, it is a substrate-verification nonconformance that must be corrected before covering. Do not sign off the wall based on the contractor's verbal assurance; the inspection record must reflect verified conditions, and any item that could not be verified should be noted as unverified pending access rather than recorded as compliant.