How to Clean Black Shower Mold Permanently

Posted by John on November 28th, 2012

Keeping with our bathroom theme… Unless you routinely scrub your tub or shower, you’re bound to get a good amount of black moldy build-up in those tough to clean areas. We’ve all seen it. Sorry if I’m starting to sounding like a commercial. It happens. It comes from years of trying to sell my ideas to Lisa. So, our master bathroom shower has seen some better days. Surprisingly, we actually DO clean it often enough that we shouldn’t have any issues with black staining mold or hard water stains, but nonetheless we do. Here’s how I was able to get our shower mold free and looking new.

How to Clean Black Shower Mold Permanently

First, I always start with a cleaning product that contains bleach. We typically use Tilex. The chemical odor can be pretty overwhelming, so whenever I use it, I try to keep the windows open to let some fresh air in and I wear a mask.  I aggressively work the cleaner into the problems areas with a stiff bristle brush.  If you still have some black mold after this step, then you’ll need to remove and replace the caulk.

Here’s what our shower looked like after the best cleaning it’s ever gotten.

shower mold

shower mold 2

black shower mold

Still pretty gross. To remove the moldy caulk, I used a box cutter with a sharp blade and a flat bladed box cutter, which is like a window scraper, to score it. Once all the caulk was scored, you can usually peel it out. Be sure to get all of the caulk out of the joints. Some of the more stubborn caulk may harden to the point that it’s like grout. The hardened stuff may need some more persuasion. I used a flat head screw driver. You do need to be careful that you don’t damage your tile or shower basin. Also, wear safety glasses. Proceed with caution and at your own risk.

Once all the moldy caulk was scraped out, it looked better.

caulk removed

after removing shower caulk

removing shower caulk 2

With all the caulk removed, it’s time to prep for the new caulk. Be sure to clean up the area where the caulk was previously. It will also need to be nice and dry in order for any caulk to adhere well.

Now, if this were a latex based painter’s caulk, I’d dive right in. The latex caulks are pretty easy to work with and are fairly forgiving. However, your shower and bathroom applications require a silicone based caulk. Silicone caulk is notoriously difficult. So, to make it easier on ourselves, we’re going to use some painter’s tape to mask off the area. I leave a good 1/4″ gap in the area where the caulk will be applied.

tape caulk joints

tape the joints

Once the tape is in place, we’re set.

Now, you can buy high quality silicone caulks that are specifically designed for a shower or bathroom application, as opposed to a window or door for example. The caulk we used for this repair guarantees several years free of mold. Hopefully, with normal cleanings, we won’t need to repeat this procedure.

Here’s a link to the caulk I’d recommend if you are considering this project.

The caulk can be applied in a thin bead and can then be smeared with your finger.

apply caulk

smear the caulk

While smearing, I try to get a seamless look. Pull your finger smoothly across the caulk line and don’t stop until you get to a corner. Once you’ve smoothed all the caulk, remove the tape. Very gently, re-smooth out the caulk lines again. You’re done. Let it dry according to the caulk manufacturer’s directions. You usually need to wait around 8 hours after you apply the caulk until you can shower.


clean white silicone caulk

fresh shower caulk silicone

Now, my assumption is the builder didn’t use a high quality caulk the first time around. We’re going to be more vigilant this time and hopefully can clean the shower with a less caustic cleaner, but I’m hoping I won’t need to repeat this for a long, long time. And if you do spot some small black mold spots in your caulk, don’t fret. Try letting the Tilex cleaner soak for a little while (few minutes) before you plan on re-doing it.

The hardest part of this whole process is removing the old caulk. Plan on this whole fix taking at least a couple of hours. It will be time well spent.

Anyone else dealing with some crappy caulk? I wrote an entire post about caulk and didn’t make one juvenile joke. #itskillingme’

This post contains one Amazon affiliate link, but feel free to purchase caulk wherever you’d like. :)

Posted in DIY Projects,Fixes,Plumbing. Tagged in ,, , , ,

Caulking the Trim

Posted by John on July 16th, 2012

Hope everyone had a great weekend! Lisa, the baby and I went up to Northeast PA on Friday evening to visit my mom and to spend some time at the local church bazaar. We’ll be posting about that stuff later this week… CAUTION: There will be pictures of delicious ethnic food. Consider yourself warned.

Saturday was my 33rd birthday!! Yikes. Getting knee deep in the 4th decade of my life here. Crazy. To celebrate, I took it easy, playing some video games and getting Thai with the family for dinner. If you’ve never had Thai food, you need to try it. I just had it for the first time in May on a work trip and I’m officially addicted. The Thai sweet iced tea is unbelievable. I’m also a big fan of Thai curries and the sticky rice. Two thumbs up.

Yesterday I managed to sneak in a little bit of house work. I caulked half of the dining room wainscoting. I’ll finish the rest of it later this week. My window sill router bit arrived in the mail early, so I may get to those caps as well.

Caulking is almost always a necessity when dealing with trim that will be painted. It’s usually applied right before you paint to close up any gaps that might otherwise be visible. You normally wouldn’t use it on stained projects since it doesn’t absorb stain. Painter’s caulk comes in a variety of colors and there are companies online that can ship you a color matched caulk if you really need it..

Whenever I use painter’s caulk, I try to use a product that has silicone in addition to the normal latex. The silicone gives the caulk some added flexibility, which means it will shrink and expand along with the wood. You won’t have to reapply it in the future or hopefully, ever again. It’s only a little more money than the plain latex painter’s caulk. Bathroom and kitchen caulks are mostly silicone. The more silicone though, the harder it is to paint.IMG_4168-e1342384234926-682x1024


For filling wider gaps, like in my wainscoting corners, I cut the top of the caulk tube further down the tube to give me a wider nozzle.IMG_4167-e1342384542596-682x1024



I try to squeeze the caulk gun with an even amount of pressure over the entire seam and I judge my application speed by how much is coming out, that way the corner gets an even amount without it getting all over the place. I’ll follow the caulk gun with my finger to even out the bead.IMG_4170-1024x682



For smaller seams, I’ll cut the caulk tube to a fairly small diameter. It’s easier to junk smaller seams up with caulk, so a small nozzle makes it easier to deliver the perfect amount and it helps to avoid a mess.

Here’s a helpful tip: Carry some paper towels with you to catch the excess caulk from the gun and to wipe off your fingers. I usually go through a lot of paper towel when I do a large room. Now matter how careful you are, it tends to get all over the place.IMG_4203-1024x682



The molding on the left in the photo below has just been caulked. The molding on the right has not.IMG_4202-1024x682


You can see a small seam on the right molding. That will need to be filled before it can be painted. You can’t assume the paint will fill those small gaps.

Here’s a close up of that un-caulked trim.IMG_42041-1024x682


If you’re not a fan of using a caulk gun, you can just put a dab of caulk on your finger and rub it into the seam. Once it’s filled, I’ll go back with a little sandpaper and sand it very lightly to knock down any high spots from the caulk. Then it’s ready for paint.IMG_4205-1024x682


You know you’ve done a quality job with the painter’s caulk if you can’t see it when it’s painted. You want the caulk to be invisible. Ideally, you won’t need very much of it. If you have large seams between molding cuts, it may be a better idea to try re-cutting them than loading them up with caulk. If you’re having trouble identifying a tough angle during a trim install, you can try this t-bevel method we posted about some time ago.

How was your weekend? Did you get any work done this weekend or did you lounge around?

Posted in Carpentry,DIY Projects. Tagged in ,, ,

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