Overflow holes are necessary to prevent your sink or tub from backing up. The problem is that they can become clogged over time, which leads to leaks and sewer backups. In this guide, we’ll show you how to seal overflow holes in the drain so that you don’t have to worry about a hefty plumber bill every time one of them gets clogged!
How To Seal Overflow Holes in Drain – Temporarily
Sometimes, you may want to temporarily seal the overflow holes in your tub drain. An example is when you are doing work on the pipes beneath the sink or tub.
Use a Drain Cover
Use a drain cover of the right diameter to fit over the drain hole. You can find metal or plastic drain covers at any home center, hardware store, or plumbing supply house. Most come with rubber gaskets that fit into the drain opening and help prevent leaks.
Install the drain cover into the overflow hole. Apply the plumber’s putty around the outside of the drain cover before installing it so it will not leak when water flows down through it.
Use Waterproof Tape
You will need a soft cloth or sponge to clean the area. Use it to remove water, soap, or dirt from the overflow holes. After cleaning the area, dry up all water to prevent it from getting into the tape when you apply it.
You can use any waterproof tape for this next step. Ensure you have enough tape to seal every inch of your drain hole without running out of material before finishing your job.
Apply the tape around the hole in a circle. Make sure that you apply the tape with enough pressure. You should not need to press hard, but you should be able to see the tape sticking to itself and not curling back up as you apply it. Repeat the process at different angles for more protection.
How To Seal Overflow Holes in Drain – Permanently
If you have a problematic overflow hole in your bathtub or sink, you may consider sealing it up permanently, especially if it leaks water. Overflow holes can be a hazard if they leak. Here are a few options:
Attach a Metal Plate Around the Hole
One way to seal the overflow hole in your drain is to use metal plates. You can buy them at any hardware store.
Step 1. Get a metal plate big enough to cover the hole
If your overflow hole is small enough (like 1/4” in diameter), you can use a piece of sheet metal and sealant for the best results.
Step 2. Use a file to remove any sharp edges around the hole
Use a file to remove any sharp edges around the hole so that they don’t damage anything when they come into contact with other objects while fixing it. You can use a file to ensure there are no burrs on edges or corners, as these can be very sharp and can cause injury if touched by bare hands or feet.
Step 3. Attach the plate to the appropriate place
Attach the plate to the right place to cover your overflow hole completely. If there are screws provided with your plate, use them to secure it. Otherwise, use other fasteners such as nails or glue to hold it in place.
Step 4. Apply sealant on the underside of the plates
Using a sealant will ensure that water doesn’t leak through the plate. Simply run a thin bead of silicone around the hole using a sharp instrument to apply it evenly. Press firmly on the plate with your fingers until the silicone starts to set up (about 10 minutes).
Apply Sealant – Alone
If you are still wondering how to seal overflow holes in the drain, we recommend acrylic-based silicone caulk. Silicone caulk is waterproof and will not allow any water to pass through it.
Other caulks, such as latex-based caulks, will eventually dry out and crack or peel off the surface, making them ineffective at keeping water out of your drains. Here is how to seal the overflow hole in the drain using nothing but sealant:
Step 1. Remove old caulk
You will need a putty knife or razor blade to remove the old caulk. A good quality putty knife will have a sharp edge that can be used to scrape off the old sealant.
A razor blade is also a great tool for removing things like dried paint, but it’s ideal for more delicate surfaces like glass and porcelain. Once you cut the sealant from the hole, pull it off using a pair of pliers.
Step 2. Clean out mold and grime
Remove mold and grime with a stiff brush. Wipe off any remaining mold with a cloth. If you have used mild detergent to clean the drain, it is time to remove it now. Use an old rag or paper towel to wipe down the inside of your drain and remove all traces of soap residue.
You can also use bleach if you want to disinfect your drain at this point, but be careful! Bleach can discolor some materials like metal or plastic, so make sure that you don’t put too much in and rinse well before proceeding with sealing up your overflow holes.
Step 3. Get the right amount of sealant
You should aim to use a sealant about 1/4 inch thick to form a complete barrier around the drain hole. If your drain has an overflow hole at the top, it’s best to use a tub-and-tile silicone caulk.
If your drain has an overflow hole at one end or side, you’ll need to use other caulking materials like GE Flexible Clear Sealant or DAP Ultra Flexible Silicone Sealant & Grout Sealer. These products have more flexibility than other types when applied around curves in pipes and drains.
It’s important not only to apply for enough coverage but also correctly so as not to leave gaps between layers where water can leak out over time!
Step 4. Apply the new sealant
Now that you have cleaned the drain and prepared an appropriate amount of new sealant, it’s time to apply it. First, place your finger in the center of the hole—this will help guide where you put your finger while applying the sealant.
Next, apply sealant and gently push down on all sides of the drain circumference with enough force to make an airtight seal. Apply a second sealant layer while ensuring even distribution around both sides of your hole to create a robust bond with the first layer.
Let this second application dry before using your bathtub or shower again. If there is water flowing through before it dries, then mold or mildew can grow inside it!
Step 5. Smoothen the sealant and let it dry
After the sealant has dried, you can use a putty knife or other tool to smooth it out. This step is important. If you don’t do it, your sealant will be rough and could be more likely to crack in the future.
Let the sealant dry for at least 24 hours before using your shower again. You may want to give it longer so that any odors emitted by new caulk will dissipate before they can annoy visitors or pets!
How Much Time Do You Have?
In summary, there are a few ways to seal overflow holes in your drain. The method you choose will depend on how much time and effort you want to put into the project. After all, sealing an overflow hole aims to prevent unwanted water from coming through it when using your tub or shower.