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Apprentice answer

Why are trim flanges not enough to anchor a large exterior louver

3rd YearRoof Curbs, Louvers & Exterior AirStop / get direction

Trim flanges are not the structural support for big wind-loaded louvers. Stop and add the approved structural mounting angles/brackets into the building frame.

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Plain-English answer

Large exterior louvers take wind load across a big surface area. Decorative trim flanges may finish the opening, but they may not be designed to hold the frame under wind, vibration, or fan pull.

Check the louver submittal, wall opening detail, and structural anchorage path. If the frame is bowing, hold the install and add approved internal angles, clips, brackets, bolts, or blocking per the louver manufacturer and structural detail.

Ask Foreman

The large louver at [location] is bowing and appears to be held by trim flanges only. I checked the anchor path. Do you want structural mounting angles added per the louver detail?

Verify before acting

Use this as training guidance. Foreman direction, approved drawings, project specs, manufacturer instructions, employer safety policy, and AHJ/code requirements always control the final answer.

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