Why does silicone on the outside not fix a leaking louver splice?

A louver splice needs a drainage path, not just face caulk. Install or correct the internal gutter/splice channel per the louver detail.

['Water can migrate through the joint between louver sections. If the joint is supposed to have an internal gutter or splice channel, smearing silicone on the outside can trap water or fail after movement.', 'Open the inside joint if accessible, check for missing gutter/splice parts, and rebuild the joint so water is captured and routed to the sill/weeps. Use the approved sealant inside the joint, not as a cosmetic band-aid on the face.']

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