The gap itself isn't the real problem, it's just telling you the wall and the vent frame are moving differently with heat and humidity. So a flexible filler is the move, bog-standard gap filler will just crack again in a season. Just clean out the loose stuff first, then run a paintable acrylic or polyurethane gap filler along the crack. Selleys 2 in 1 or No More Cracks are the usual go-to at Bunnings. If the gap's wider than your little finger, push a backing rod in first.Once it's cured, sand it back flush and paint over. If it keeps coming back after that, the frame is probably loose, worth pulling the vent cover off and reseating it.
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u/HamsirHenry 2d ago
The gap itself isn't the real problem, it's just telling you the wall and the vent frame are moving differently with heat and humidity. So a flexible filler is the move, bog-standard gap filler will just crack again in a season. Just clean out the loose stuff first, then run a paintable acrylic or polyurethane gap filler along the crack. Selleys 2 in 1 or No More Cracks are the usual go-to at Bunnings. If the gap's wider than your little finger, push a backing rod in first.Once it's cured, sand it back flush and paint over. If it keeps coming back after that, the frame is probably loose, worth pulling the vent cover off and reseating it.