Is Cedar Waterproof?

Is Cedar Waterproof?

Handyman's World is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

If you are planning to build something for outdoor use, real wood is always a fantastic option to consider. That said, there are many different types of wood that you can use for purposes such as decks, fences, and furniture.

One type of wood that is quite popular for outdoor use is cedar, and this is true for many reasons. This material is fairly durable, looks nice, and handles the elements pretty well too. So, is cedar waterproof? How well does it handle the elements, and what happens if it gets wet?

Is Cedar Naturally Waterproof?

Just to be clear, while different types of wood can be water or moisture-resistant to a certain degree, no wood is 100% waterproof.

Although some types of wood do fine when constantly exposed to moisture, and sometimes even submerged in water for prolonged periods, even for years, all wood will eventually start to absorb moisture.

However, there are of course some types of wood that are much more resistant to the elements than others, and yes, cedar is one of them. In fact, as far as moisture resistance over the long run is concerned, this wood is one of the best options out there, and this is true both for softwoods and hardwoods.

Cedar is of course a softwood, which is why some people might be surprised that it is as moisture-resistant as it is. Yet, for things like decking, fencing, and outdoor furniture, cedar is a fantastic option to consider, especially if you seal or treat it for added waterproofing benefits.

Does Cedar Absorb Moisture?

Once again, all wood will start to absorb moisture with time. It may take a lot of moisture, even to the point of being submerged, and it may take many years, but all types of wood will absorb water given the right conditions.

That said, as far as moisture absorption is concerned, cedar is up there with the best of them, which is why it is such a good option for outdoor use. This material does not easily succumb to moisture, and this is with prolonged exposure to fairly high levels of water.

For one, cedar has a fairly tight grain, and it is somewhat dense. Because of this, moisture cannot easily penetrate the surface. If moisture cannot penetrate the surface easily, then the inside of the wood should be relatively well protected from the elements. Even if after a few years the outside may start to absorb a little moisture, the center of the cedar board should remain quite dry.

On that note, this wood doesn’t have a high moisture content to begin with, which is a definite bonus on this front. The moisture content of cedar is generally much lower than with most other types of softwood. Wood that has a low moisture content also doesn’t absorb moisture easily, which means that it stays much drier for longer, even in the face of moisture.

Finally, cedar also contains a good deal of natural oils that act as water repellents. The oils and resins contained in the wood are natural waterproofing agents, and on that note, are also ideal for repelling pests of all kinds.

Does Cedar Rot When Wet?

Just like with the other sections here, yes, cedar will rot eventually, just like all other types of wood will. This is an organic and carbon-based material, which means that it does eventually rot. However, when compared to other types of wood, cedar is much more rot-resistant.

First and foremost, cedar doesn’t have a high moisture content, nor does it easily absorb water, and of course, it takes moisture and humidity for the rotting process to occur. If this wood doesn’t absorb water, or at least not much, it means that it will also take a long time for it to rot.

However, what also needs to be noted about cedar is that it dries out very quickly. So, on the off chance that it does absorb a substantial amount of water, it should dry out fast enough to prevent any rot or decay from setting in. At the same time, the natural oils and chemicals in the wood help kill mold and fungus, therefore usually stopping those issues from occurring.

Does Cedar Expand When Wet?

Cedar may expand slightly when wet, just like all other types of wood. However, due to its low moisture content and its resistance to absorbing water, this problem should be minimal.

How to Waterproof Cedar

If you plan on using cedar outdoors, even though it is already very water resistant on its own, it is a good idea to seal it with an appropriate sealant. We could talk about a dozen different sealants that you could use, but there is really nothing better than linseed oil.

This type of sealant will last a long time, is durable, doesn’t require reapplication too often, and is clear, which means that it preserves the natural appearance of the cedar underneath. Follow the steps listed below to waterproof your cedar.

Step 1: Clean the Wood

Use a slightly damp cloth to clean the cedar boards being treated. You don’t want any debris present. You can then use a dry cloth to make sure it’s totally dry and free of any and all debris.

Step 2: Apply the Sealant

Place your cedar board on a flat surface and use a paintbrush to apply a thin layer of the linseed oil sealant. Wait for it to dry according to the instructions. You can then flip the board over and apply a layer to the other side and the edges.

Step 3: Reapply and Let Dry

If you want the maximum amount of protection possible, wait for the first layer to dry, and then apply a second layer.


In the grand scheme of things, cedar is one of the more water-resistant woods out there, but you do still want to seal it for the best results when using it for outdoor purposes.

Also, keep in mind that to an extent, the water resistance properties depend on the type of cedar you are using.