How can you tell if an exterior intake louver is installed the wrong way?

Stop before siding/sealing finishes. Louvers have drainage/weather orientation; verify label/blade direction and reinstall per manufacturer/detail if water can be driven into the building.

['An exterior louver is not just a grille. It sheds rain, blocks debris, and directs air. If the blades pitch the wrong way, the louver can collect water and dump it into the wall, plenum, or mechanical room.', 'Verify the manufacturer orientation, drain sill, bird screen side, airflow direction, and wall flashing before cover. The likely fix is to pull and reinstall the louver correctly, then reseal/flashing per the approved exterior wall detail.']

Stop if

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

Check

• A reversed louver can cause serious water intrusion, wall damage, equipment damage, and callbacks after the first storm.

Steps

• Check blade slope, drain sill, weep path, bird screen side, and orientation labels.
• Look from outside to see whether rain would shed out or funnel inward.
• Verify exterior wall flashing and sealant sequence.
• Stop adjacent finish work if the louver has to be removed.
• Photo the condition before correction.

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