13 DIY Tips for Caulking Your Bathroom Sink

Is the caulk around your bathroom sink stained and discolored? Worse yet, are there cracks in the caulk around your bathroom sink? Or does the caulk show signs of mildew? Then it’s time to re-caulk that sink and improve the look of your bathroom with this easy and inexpensive project.

TIP #1 – Check the caulk around your bathroom sink and faucets regularly.

You should re-caulk if:
– there are any cracks in the caulking
– the caulk around your bathroom sink is becoming hard and brittle
– the caulking is pulling away from the sink or the counter-top
– there is mildew on the caulking that cannot be washed away, or returns soon after being cleaned
– there is moisture under the sink and there are no leaks in the plumbing or fixtures

You may want to re-caulk if:
– the caulking around your bathroom sink has become stained and discolored from soap scum and grime

TIP #2 – Never ignore damaged caulk around your bathroom sink.

The caulk around your bathroom sink has an important function. It keeps water from leaking onto surfaces below the sink or adjacent to it. If the caulk is cracked or damaged then those surfaces will be damaged. It doesn’t take a lot of water to do a lot of damage. Over time even a small crack in the caulk can allow enough moisture to penetrate to allow mold, mildew or rot to take hold. Mildew and water damaged wood is more susceptible to insect attack.

The bad news is that ignoring damaged caulk around your bathroom sink can lead to expensive repairs and serious health problems.

TIP #3 – Re-caulking your bathroom sink is an easy inexpensive DIY project.

The good news is that there is no reason to avoid re-caulking your bathroom sink. It’s an easy DIY project for a novice to tackle. Most of the tools you need are ones that you probably already have. This is an easy inexpensive DIY project that will improve the look of your bathroom and can prevent the kind of serious damage that leads to expensive repairs down the road.

TIP #4 – Surface preparation is everything!

The most important thing I can tell you about re-caulking your bathroom sink is that surface preparation is everything! I cannot emphasis this enough. You must completely remove ALL the old caulk; carefully clean the surface; and completely dry the surface before applying the new caulk.

TIP #5 – Choose a caulk with a mildew killer in the formula.

There are a lot of choices for caulk and some of them are specially formulated for kitchen and bath areas. This is an inexpensive project so there is no reason not to pay a bit extra for a good product. I recommend you either use a PVA (polyvinyl acetate) caulk or a Silicone caulk. Both have advantages and disadvantages. A 100% Silicone caulk has a very long life. It is completely waterproof, which makes it ideal for the bathroom. But it is difficult to work with and very hard to completely remove if you ever need to replace it. Nothing (including new Silicone caulk) will stick to it once it has cured. A better choice may be a PVA caulk. Several of these have mildewcides added. That’s a good thing in a caulk for your bathroom sink. If you decide to go with a Silicone caulk, look for GE Silicone II with BioSeal. Two good PVA caulks with mildew killer are Polyseamseal Tub & Tile Adhesive Caulk and DAP Kwik Seal PLUS Kitchen & Bath Adhesive Caulk with Microban.

TIP #6 – Use caulk in a squeeze tube for this small project.

The traditional large tube of caulk and a caulking gun will work fine and by all means use it if you have one available. But the smaller squeeze tubes are easier for a novice to control. Re-caulking a bathroom sink is a small project and most homeowners will not use up all the left-over caulk in the larger tube before it goes bad.

TIP #7 – Remove soap scum and grim from the surface before you remove the old caulk.

It seems odd to do this now. You may wonder why you shouldn’t wait until after removing the old caulk since the surface will need cleaned then anyway. But this two phased cleaning is important. Before removing the old caulk, clean the surface thoroughly with a good bathroom cleaner. Get all the grim, and especially the soap scum. Then rinse with clear water several times. Dry well. By doing this before removing the old caulk you avoid getting the newly exposed surfaces wet. A dry surface is critical when applying the new caulk.

TIP #8 – Use this inexpensive formula for killing any remaining mildew.

Mix 1 quart of liquid chlorine bleach with 3 quarts of warm water and 1/3 cup of powdered laundry detergent. Mix well and either apply with a sponge or a spray bottle. Rinse well with clear water.

It’s very important that you have adequate ventilation when you use this solution. You should also wear gloves and eye protection!

TIP #9 – There’s no replacement for elbow grease but there’s help on the way.

Removing the old caulk is the most time consuming part of this project. It’s important to remove all of the old caulk and it mostly just takes time and perseverance. However, there are several products available that can help. Which one depends on what kind of caulk you are removing. If it’s still a bit pliable and soft then it is probably Silicone. Otherwise it is a latex or PVC. Armed with your best guess, visit your local home improvement center and ask which caulk remover to use. Three common ones are Dap Caulk-Be-Gone, 3M Caulk Remover, McKanica Silicone Caulk Remover Gel.

TIP #10 – After removing the old caulk, clean the surface with alcohol, not water.

Make sure you have removed all the old caulk from around the bathroom sink. Then wipe the surface with denatured alcohol. If the joint is deep, vacuum it out first. By using alcohol instead of water, the surface will be nice and dry when you apply the caulk.

Unfortunately, if there is any remaining mildew, you will have to use the bleach formula again. Use as much as necessary to kill the mildew but try not to saturate the surface. Remember, you will have to dry it thoroughly.

TIP #11 – A hair dryer will speed up the drying process

The surface must be absolutely dry before applying the caulk. You can use a hair dryer on the surface if you can’t wait until the next day.

TIP #12 – Less is more when applying caulk.

When you cut open your tube of caulking, make the opening small. You can always make it bigger if necessary. You want to lay down a small bead of caulk around your bathroom sink. If you apply too much it will make the clean up process much more difficult.

The bead of caulk should fill the joint. If you miss a spot, go back and fill it. Don’t leave any air pockets. Work quickly before the caulk develops a “skin”. After applying the bead of caulk use your slightly moistened finger to lightly press the caulk into the joint between the sink and the counter-top. This will also give it a nice finished look.

Let it cure overnight (or according to the product directions).

TIP #13 – enjoy the fruit of you labor.

Congratulations – You did it. You caulked your bathroom sink and it looks great.

Allen, Benjamin W., ed. New Complete Guide to Home Repair and Improvement. Des Moines, Iowa: Meredith Books, 1997
Polyseamseal Tub & Tile Adhesive Caulk“, Polyseamseal home page
DAP Kwik Seal PLUS Kitchen & Bath Adhesive Caulk with Microban“, DAP home page

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