The DIY Guide to Curing “Countertop Cancer” During Your Sink Replacement

If your countertop is swelling, bubbling, or soft around the sink, you’re dealing with what many installers call “countertop cancer.” It’s a slow form of water damage caused by years of moisture seeping under the sink rim. Ignoring it can lead to total countertop failure—but fixing it during sink replacement can stop it for good.

Begin by removing the old sink and inspecting the cutout edges. Any soft, dark, or crumbly areas must be removed completely. Use a scraper or utility knife until you reach solid, dry material. Leaving even a small damaged section allows moisture to spread again.

Once exposed, treat the area with a wood hardener or epoxy filler. This reinforces weakened surfaces and restores structural integrity. After curing, sand the area flat so the new sink sits evenly.

Before installing the new sink, seal every exposed edge with 100% silicone or waterproof sealer. This step is critical—especially for laminate countertops.

At I Hate My Sink, we’ve saved countless countertops by addressing water damage at the right moment. Sink replacement isn’t just cosmetic—it’s your best chance to stop damage permanently.

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