Excess mixing water can evaporate or trapped air can escape, leaving small voids in a joint. A few shallow holes in firm grout are usually surface defects, but deep holes, crumbling grout, or signs of leakage need attention.Repair defects in wet areas rather than covering them with sealer. Sealer can’t replace missing material or repair waterproofing behind tile.
Check the damage and make sure the surrounding grout is sound.
What Causes Grout Pinholes?
Small openings that appear soon after installation usually point to mixing, packing, or cleanup problems. Settling and movement more often cause cracks than round holes.
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