Caulking is essential for any home. Everyone, from seasoned property owners and managers to everyday folks like yourself, knows that caulking is as important as reroofing or insulation. In fact, you’ll find it hard to locate a single home in your own neighborhood that doesn’t have at least some level of caulk somewhere. And if applied well, that might just be the only bit of caulking you will need in years.

However, like everything else, this material deteriorates over time thanks to either wear and tear or the elements. At some point, you’re going to have to replace that old caulk. But some people tend to simply apply a new layer of caulk over the existing one. Should you do it, then?

In this article, I will cover everything you need to know about recaulking and why it might (or might not) benefit your home. But before we move on, let’s quickly cover what caulk is and what you can use it for.

Different Types of Caulk

Caulk is a type of material that you can use to seal seams or joints in pipes as well as various structures (buildings, houses, etc.). Normally, you use caulk to seal gaps in order to prevent water, dust, air, or insects from coming through.

Let’s just say, for the sake of argument, that you’ve never done caulking before in your life. As a complete beginner, you would need to figure out what the best type of caulk is, since there are so many to choose from when you enter the store or browse products online.

Before buying caulk, you need to figure out a few key details, such as:

  • Where you will apply it (wet vs. dry areas, outdoors or indoors, etc.)
  • What material you plan on caulking (plastic, wood, concrete, etc.)
  • How durable you need it to be
  • Can you paint over it or not

Best Solution for Wet Surfaces

Some areas of your home will always be exposed to a certain amount of water. For example, your entire bathroom is essentially one huge area that requires waterproof caulking, be it around the bathtub, the shower cabin, the toilet, the sink, the drain, or the window. Improper caulking can lead to cracks, peeling, and other types of damage, which is the prime reason why some people want to recaulk over the existing, damaged layers.

By far, the best two options for wet surfaces include polyurethane and silicone caulking. Each of these two options is known for its spectacular flexibility. In addition, they don’t crack or damage easily, even if you constantly expose them to water or generally moist environments. Plus it has the added benefit of not requiring a recaulking job for a long time after you apply it.

You may also like to know: What Happens if Caulk Gets Wet Before It Cures?

Best Solution for Submerged Surfaces

More often than not, you will require a good caulking material that can stay strong and durable when submerged underwater for long periods of time. For example, boat owners have to maintain the bottom of the boat and seal every point where water might enter. The same goes for people who own pools or fountains, both fixtures which have to contain a body of water 24/7. Even some large aquariums and garden ponds have this issue.

So, in order to keep those surfaces safe and caulked, you will need some strong polysulfide solution. It stays durable in both dry and wet conditions, but it’s most effective when submerged. Out of all the sealants and caulking material out there, polysulfide is the one you will probably not going to recaulk for a long time.

Best Solution for Molding

Wooden molding is prone to having gaps, which is why people need a decent, non-flexible caulking solution for it. So, if you want to fill in the molding gaps in windows, doors, and other areas around the house, you’ll need an acrylic latex product. Its main benefit is that it stays firm and durable for years. In addition, you can paint over it if you want to even out the colors between the caulk and the wood of the molding.

There are, of course, other various types of caulk that we can use in nearly every single facet of the building industry, from fireproofing to mortar repair. However, when it comes to recaulking, the four solutions listed above are the most common DIY choices.

Can You Caulk Over Caulk?

The short answer is Yes. However, you need to do some research before you decide on doing it.

For instance, some surfaces, like pure silicone, will not stick to anything (including silicone itself). In other words, you can’t really caulk over an existing layer of silicone and expect it to hold. Of course, that still shouldn’t stop you from applying a wide, thick layer of any other caulk, which will stick to the non-caulked sides around the silicone layer underneath. 

Recaulking 101: Things to Keep in Mind

Before you decide on recaulking, you have to make sure that the old layer of caulk is not dried up. However, if it is dried, and you have no other option but to apply a new layer on top, you’ll have to keep the following in mind:

  • Make sure that the surface you want to apply the new caulk on is clean and contains no dust. If you see some dust on the old layer of caulk, simply remove it with a dry, clean cloth.
  • There should be absolutely no water or any other liquid on the dry layer of the old caulk. When you spot any liquid, take a tissue or a dry cloth and gently soak the substance up with it. If you can, use a fan to dry up the wet spot a bit faster.
  • Only apply the new caulk once the old layer is clean. There mustn’t be any debris, liquids, dust, or other obstructions.
  • Make sure that the caulk you’re using and the old layer you’re covering are both made of the same material. If they aren’t, the new layer won’t ‘stick’ and you can end up recaulking the whole thing all over again.

The Pros and Cons of Recaulking

As you can see, putting new layers of caulk on top of the old ones is entirely possible. In fact, more people do it than you’d think; a search for the phrase ‘can you caulk over old caulk’ gets over 36 million hits on Google.

Of course, recaulking has its benefits and its flaws, so let’s go over a few right now.

The Positives of Recaulking

Let’s say that you’ve used acrylic caulk for your kitchen sink, and that you spotted a gap where there’s a leak. When you use the same material (i.e. acrylic caulking) to go over the old layer, you are guaranteed to cover that leak swiftly.

In addition, by applying a new layer of caulk, you’re covering deep, wide leakages and filling them up. With the previous caulk acting as a strong basis, you will have no problems with future leaks.

The Negatives of Recaulking

Of course, not even the best caulk on the market can stay firm and durable forever, and not every new layer of caulk will stick to the old one (even if they are made from the same material). In time, they will separate, and if the old layer is particularly weak, they can separate as soon as a few hours after you’ve applied them.

Once again, I have to stress that you need to clean the old layer of caulk carefully. Any speck of dust or dirt can create a ‘bubble’ that leaves the material open for leakage.

When Should I Avoid Recaulking?

Two of the biggest reasons for recaulking are cracking and mold growth. People often ask if they can and, more importantly, should apply a new layer of caulk on these surfaces.

In terms of cracks, you first need to check the condition of your old layer of caulk. It’s important that the basis is stuck to the surface and well-placed. If it doesn’t move about, you’re good to go. However, you should still check the caulk for any signs of mold.

And speaking of mold, never try to apply a layer of new caulking onto the moldy basis. The mold will stick to the new layer of caulk, but it will continue to grow and eventually, it will split the two layers and you’d have to recaulk everything all over again.

Recaulking: the Conclusion

Simply put, applying a new layer of caulk over an existing one is not just possible, it’s something that literally millions of people around the world are doing. As long as your base caulk is clean and relatively whole, feel free to apply as many new layers of caulking as you want.

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