Is there a standard way to apply caulk and is it difficult to do?

November 17, 2023 9:46 AM

I have now attempted several times to apply caulk in my bathroom and each time the final results are terrible. Here's a particularly embarrassing but representative example. My question: Does applying caulk actually take a bunch of skill and experience or is it straightforward and I'm just doing it wrong?

The interwebs are full of "caulking hacks" and contrary advice. I'm wondering if there's a simple set of instructions that Just Works.

posted by O Time, Thy Pyramids to Home & Garden (18 answers total)

Yes, cauking neatly is a skill and requires practice. A few tips, but, mostly, try stuff out on a practice surface, or be prepared to rip out and re-do. These are general tips and all of them may not apply to this specific situation.

• Small beads are preferable unless you need to fill a giant gap. Cut the tip at a 45 degree angle, and as small as you can--you can always make it larger.
• If you have a truly large gap, you should not be filling it all with caulk. Use foam backer rod of the appropriate size.
• Lead with the tip, don't follow (this is confusing and I've heard the same advice stated in different and possibly contradictory ways; it's a good one to pick up from videos).
• If the surface you're caulking is uniform and will accept the adhesive, try masking the bead with painter's tape.
• To smooth a bead, spray both the uncured caulk and your finger with water plus a very small amount of dish soap, and run your finger along it. You can buy little tools for this but I feel like fingers always work better and are more responsive unless you need to smooth a bead that's the wrong size or inaccessible to your hand.
• Work fast, or in short sections if you're slow. If the caulk forms a skin it will hang up and not smooth out acceptably.

posted by pullayup at 9:54 AM on November 17, 2023 [15 favorites]

Also, latex caulk is a lot easier to apply than silicone. So if you can use latex, give it a try.

And some caulk guns are just no good and make it impossible to apply a consistent bead. If you can borrow a nice one from a friend or local tool library it may make the difference.
posted by pullayup at 10:02 AM on November 17, 2023 [2 favorites]

Tape it.
posted by bluesky78987 at 10:11 AM on November 17, 2023 [1 favorite]

It's hard to tell scale of that pic but I wonder if the gap is too big for caulk alone, or too big for the size hole you cut in the caulk tip. If the former, you need backer rod to fill the gap first. If the latter you can cut the tip farther back so the hole is bigger. I can do ok with small gaps but big ones always look like shit for me.
posted by misskaz at 10:41 AM on November 17, 2023

When redoing our (and a friend’s) bath/shower, the thing that was most useful was taping, then spraying with a soapy water mixture and using a clean finger. Other specialized caulking tools helped, but were harder to get a feel at times.
posted by raccoon409 at 10:47 AM on November 17, 2023 [1 favorite]

Using a wet finger to smooth the caulk is Top Tip #1.
posted by Dr. Wu at 11:15 AM on November 17, 2023 [5 favorites]

Caulking is pretty straightforward. Just squirt a bunch in the crack and then immediately smooth it all out with your finger. Don't worry about getting too much or too little — too much and you'll wipe the excess away with your finger, too little and you can just caulk again.
posted by TurnKey at 11:33 AM on November 17, 2023

Hello, I am an apartment maintenance person and I do caulk regularly. I am not as professional as a construction worker who does it for hours at a time but I'm pretty good at it!
It does not matter if you lead or follow with the caulk gun, because you want the smallest bead you can do at a time. Do a couple feet and then swipe it gently with your wet finger. You do not need soap, just a little water. You're foing to want a bunch of rags to wipe your finger off with, because the caulk will dry around the sides of your finger. I have started doing the swiping with a wet rag around my finger, and then for the next swipe i use the next couple square inches of wet rag.
I do recommend those little swiping tools made of silicone like a weird kitchen implement, because they'll make it look uniform. They're just hard to clean so i don't use them habitually.
Put a small bead down of 1-2 feet, then swipe it along the seam. Some of the caulk will disappear into the seam, some will get pushed along the seam a little farther than you initially put. If any of it got spread too thin, you can add more little beads or dots, then swipe over it again and again. You want it to disappear into the corners a little bit if there's space for it.
If your bead is too fat, it will collect on the sides of your finger/tool instead of going into that little 90 degree corner, and end up making two little extra trails on either side. That's why i say to initially apply the smallest bead you can. If you cut the application end of your caulk tube very small, it will take a little longer to squish out, but it will be very controlled.
Just do it a couple feet at a time. Most caulk will begin to dry around the edges of its bead within 5-10 minutes so you don't want to be dealing with little dried flakes while you're smoothing it. So only add more bead once you've finished smoothing a 1-2 foot stretch.
It's an art, not a science! Worst case scenario, dried caulk should be able to be peeled off and scraped off.
I don't like using silicone because when it's cut or removed it disintegrates into a million dirty fragments of rubbery yuck like some kind of used up Nickelodeon goo. I prefer caulk which stays in large pieces.
posted by panhopticon at 11:33 AM on November 17, 2023 [17 favorites]

This guy's video on caulking is going to be my primary source of aid and comfort if I ever get to the 80+ caulking projects all over the house.
posted by Don Pepino at 1:21 PM on November 17, 2023 [1 favorite]

(He also has this one on which caulk to pick.)
posted by Don Pepino at 1:24 PM on November 17, 2023

Hi!
I watched approximately 20 videos on caulking during a very very frustrating project recently.
this one was helpful
this one, too

My takeaways from everything were:
1) cleaning and prep are more important than I'd like them to be
2) push the caulking into the cracks (by angle of application) where possible
3) GET THE SPECIAL SPREADER TOOL

the last one always seemed so ridiculous - I've done this type of job with wet finger and/or tape a dozen times, but this time I used neither and the results were the best I've ever accomplished.

Good luck!
posted by Acari at 1:30 PM on November 17, 2023 [2 favorites]

I'm sure there are many ways to apply caulk, but here's how I do it:
-Lay down blue painter's masking tape on either side of where you want the caulk to be.
-Use the caulking gun to put down a bead of caulk that doesn't quite reach the edges of the painter's tape
-Wrap a fingertip in a piece of plastic bag and run it along the bead of caulk to smooth it. If you're smoothing a lot of caulk - say, a shower enclosure, you may want to have several pieces of plastic bag ready as they may load up with excess caulk.
-Pull up the painter's tape before the caulk dries.
posted by zombiedance at 2:14 PM on November 17, 2023 [1 favorite]

It is definitely a skill that requires practice. If it's something you only do once or twice a year there is going to be some frustration involved.

I can be sloppy so I put down tape on either side of the line where I'm applying caulk. The idea is to have the caulk, having been smoothed with a wet finger, barely touch the edges of the tape. There should be minimal visible edges when you pull off the tape.
posted by Tell Me No Lies at 6:58 PM on November 17, 2023

As mentioned above, a poor caulk gun makes the job so much harder. The cheap $5 models with like a 3:1 or 5:1 thrust ratio take a lot of grip strength to use, which can make for sloppy beads. It's worth spending a bit more to upgrade to a model with a thrust ratio in the neighborhood of 10:1 or 12:1. With the higher-ratio guns, you'll generally dispense a bit less goop with each squeeze, but they are so much easier to use that I think the tradeoff is worth it. The ratios do go higher, but those are really for thicker materials like epoxies and construction glues. For a home DIYer, don't bother with the battery cordless models; they still require the same set of skills to use well, and are 10x the price.

As others have said, you want to snip off as little of the tip as possible from the tube, to produce the smallest dispensed bead of caulk. A gun with a higher thrust ratio will make it easier to squeeze the caulk from that smaller hole, and do so with better control.
posted by xedrik at 9:56 PM on November 17, 2023

If you are skilled, you can "push" a clean and concave bead with the tip and you don't even need to do the finger thing. I achieved this exactly once in my life and I've been chasing that high ever since, plan accordingly.
posted by dbx at 4:33 AM on November 18, 2023

Champions, I very much enjoy watching @martyncoops on TikTok who does nothing but post videos about applying mastic (what we call caulk in the UK). He swears etc - he works on British building sites - so I leave it to you whether he might be your cup of tea. But I often find him funny and his technique is unstoppable.

This video is his general how-to.

You're best off watching his videos for tips, but contrary to what others say above he'd tell you to keep your "meat spanners" well out of it and use a piece of wood, cut at an angle (here's how), or a tool designed for the task. Spray it and the mastic with dilute water + washing up liquid.

My results have got a lot better since following this. Plenty of room for improvement though.
posted by fabius at 8:46 AM on November 18, 2023

mastic (what we call caulk in the UK).

Sorry, just to correct myself - we do have caulk in the UK, as well as mastic and sealant... the definitions, differences and overlaps between the three seem to vary depending on what I read.
posted by fabius at 4:47 PM on November 18, 2023

Getting a consistent, perfect line without tape takes a lot of practice. For someone that just does it occasionally (eg me), I use the following method and get great results:

1. Clean the surfaces thoroughly, particularly making sure there's no old caulk around the edges of the caulk line.
B. Tape off the whole thing, so there's a line of tape down each side of every part of the corner or whatever you're caulking. Use a very sharp blade around internal corners so the whole thing can be done at once.
3. Get everything you need ready to hand - caulk and gun, rag/s, water with a little dish soap in a spray bottle and one of those silicone tools designed for this job.
IV. Cut the nozzle to a size where you can get a decent bead in one sweep of the gun.
5. Squirt the bead in one line at a time (eg one corner in a shower), then run the silicone tool along to make a neat bead (spray just the tip of the tool with the water before and frequently during after wiping the excess caulk off the tool with the rag). Do this to all adjoining joints in one go.
6. Quickly, but carefully, pull all the tape off and put it somewhere it won't spread goo all over the place.
7. Spray all the joints you just pulled the tape off with the water.
8. Run the silicone tool over all the joints - the aim is to just flatten the edges of the bead without squeezing too much out and this will remove the sharp lines at the edges left by the tape.
9. Stand back and marvel at your skill.
posted by dg at 8:10 PM on November 19, 2023