Is Clay Waterproof?

Have you found yourself wondering if clay is waterproof or not? Maybe you are wondering if your clay sculpture could survive outdoors in the rain?

Or are you curious and want to know more? No matter what your question is that brought you here today, we have the answer for you!

Is Clay Waterproof (1)

When it comes to clay, it is common to have questions about it. After all, if we transform it from a malleable ball or block into works of art, we are bound to wonder about its properties!

But is clay waterproof? You head online in search of answers but are met with conflicting information and unhelpful articles. How is this supposed to give you the answers you need? And what are you supposed to do now?

Well, you can stick with us! Today, we are here with the answers that you need. Keep reading to find out if clay is waterproof and everything else you need to know about it! 

What Is Clay And Its Different Types?

Before we get into today’s article, let’s have a quick recap for those that need it. Clay is a type of fine-grained soil material made up of clay minerals.

It forms as a result of erosion and weathering of rocks that contain feldspar (the mother of clay) over long periods. 

Clay has been used for generations to make things, from bowls and plates to bricks and even musical instruments! It’s an incredibly diverse material and one we are sure will continue to be used for generations to come too. 

Clay changes depending on what is exposed to, becoming hard and brittle when fired (heated by fire or kilns to extremely high temperatures), develops plasticity when wet, and drying out when left out in the open.

It is these changes in clay that make it diverse and so useful to us! 

These days, clay is commonly used in pottery or ceramics, where the clay is cut and molded into the desired shape before it is fired, painted, and glazed.

The result is a shiny finish on the product like a bowl or vase that is sure to stand the test of time! 

There are lots of different types of clay, but they will all fit into one of these three main categories: porcelain, stoneware, and earthenware.

You can identify what type of clay you have depending on the temperature they need to be fired at and the qualities of the clay.

If you are purchasing the clay from a store or online, the type will be printed on the packaging along with any information you need about firing the clay. 

Now that we have covered what clay is, let’s move on to see if clay is waterproof or not! 

Is Clay Waterproof (1)

Is Clay Waterproof?

Let’s get straight into it! Clay that we find as a result of weathering and erosion is waterproof. Clay soil in its natural state might absorb a fair amount of water, but as water or rain falls on the clay, it should simply run off!

Clay used in ceramics and art is also waterproof, when we fire clay in a kiln or glaze it, the clay does become waterproof! 

The heat that clay is exposed to in the kiln, or the properties of any glaze you put on the clay will change the clay’s properties. In these cases, the clay will harden and become waterproof.

The glaze provides an added layer of protection, and you will see that the water cannot enter the clay, instead, it will roll off the clay. 

When selecting a glaze to use on your clay, be sure to look for one that promises to make your clay waterproof. This is essential if you are putting your clay structure or sculpture outside.

The glaze will provide added protection from harsh winds or rains and ensure that it won’t be damaged by water. Of course, if there is an adverse weather warning, it might be best to move your clay structure indoors or cover it and tie it down if necessary.

The last thing you want is to wake up and find it damaged or blown into your neighbor’s yard! 

Different types of clay are waterproof in different states. Clay soil, as we mentioned earlier, can both absorb water and keep water out!

It will absorb water at a rate of less than ¼ inch per hour, which means it would take a lot of consistent rainfall or water to be sitting on top of the soil for it to be absorbed!

It can also hold onto this water tightly, which can make it difficult for plants in clay soil to get the moisture they need. 

Polymer clay is waterproof before and after it is baked (or fired in a kiln). This is due to the oil in the material, but it is still recommended that you don’t leave it in water too long.

After all, even the most waterproof of materials can eventually be undone by water! It is best to keep your clay away from water where possible, even if it has been baked and glazed! 

Clays that air dry and aren’t fired in a kiln can also be made waterproof providing you treat them with the correct paint or glaze. This will help them repel water rather than absorb it.

If your clay has any water or excess moisture in it, it won’t dry correctly and those fired in a kiln can even crack when the water and heat meet! It’s not a chance you want to take!

Final Thoughts 

And there you have it, clay is indeed waterproof! How waterproof clay depends on the type of clay and whether it is in its natural state, air dried, or fired in a kiln.

By adding a resin, paint, or glaze to our clay we can protect it from the elements and make it waterproof, but where possible avoid overexposure to water to keep your clay items or sculptures intact.