The best fix is to cut them out and replace them.
Replacing cabinet bottom under kitchen sink.
The sink cabinet measurements are going to determine exactly what size sink you can install.
Remove the cabinet door or doors for a double sink to allow better access to the area under your sink.
The flimsy particleboard bottoms in most kitchen and bathroom sink bases are often swollen and moldy from leaks.
Replacing the bottom piece of wood.
Damp rotten particleboard holds water which promotes mold and mildew.
We ll never understand why cabinetmakers use.
When replacing a sink it s important that your new kitchen sink be the same bowl size sink width and sink depth of your current sink.
Replacing the bottom piece of wood under the sink with a mold resistant pressed cement.
How to replace the bottom piece of wood under my kitchen sink.
Let s face it it s easy to get water on the floor of your sink base cabinet.
Damp rotten particleboard holds water which promotes mold and mildew.
Moisture destroys the particleboard most cabinets use for the floor below a kitchen sink.
If you have a particle board floor underneath your sink that is showing signs of water damage you can tear it out and replace it to prevent the growth of mold.
Btw some sink areas have a gap in the framing bottom panel connecting to a forced air vent or rarely to a hydronic heating loop or bare pipe or radiator be sure to leave that open if you have such because that is designed to keep the under cabinet area and pipes warm to prevent pipe freezing.
Moisture destroys the particleboard most cabinets use for the floor below a kitchen sink.
The space beneath the kitchen sink is exposed to high levels of humidity and may even be exposed to water through leaky plumbing.
Over time this can cause the wood under the sink to rot.
Otherwise you may have to replace your cabinet too.
Then cut the caulk.
Start by measuring the depth of your cabinet.
If the caulk is too hard to cut hammer an old putty knife.