How should inactive sections of a louver be blanked off?

A louver blank-off needs to be rigid, sealed, weather-aware, and mechanically fastened. Cardboard/tape is not a permanent blank-off panel.

['Partial louvers often have active and inactive areas. The inactive area still sees wind, rain, fan pressure, and pressure changes, so a temporary patch can blow out, leak water, or bypass outside air.', 'The fix is to fabricate/install the approved blank-off panel or insulated panel detail, fasten it to the louver/frame properly, and seal the perimeter for weather and air bypass. Confirm drainage/weep paths are not blocked.']

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 bad blank-off can blow out, leak water, bypass outside air, and create noise or comfort problems.

Steps

• Identify active vs inactive louver area and what duct/plenum connects behind it.
• Check pressure direction, weather exposure, drain/weep path, and insulation needs.
• Remove temporary patch material and inspect frame attachment points.
• Fabricate/install approved rigid blank-off panel and perimeter seal.
• Restart/check for air bypass, rattle, and water path.

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