Why Does Cedar Wood Split? 10 Causes and Fixes

It’s a common problem: you bring home a new cedar board or beam that starts to split after a few weeks. You may be wondering why this is happening and what you can do to fix it. Here’s everything you need to know.

Cedar wood splits when the water leaves the cells faster than it can be replaced. This usually happens when the wood is exposed to sunlight or left in an uninsulated barn in the winter. It can also happen if the wood is stored near a heat source for a prolonged period.

This article will explore the most common causes of cedar splitting and how to remedy them. Read on to keep your cedar wood in the best possible shape.

What Is Cedar Wood and Why Does It Split?

Cedar is a softwood that is light in color, ranging from pale yellow to reddish-brown. And it has a distinctively fresh, evergreen smell. Cedar is often used for its beauty and durability in outdoor applications such as fencing, decking, siding, and shingles. A deck substructure can last up to 40 years if it’s made of cedar. [How Long Does a Deck Substructure Last?]

Why does cedar wood split

Cedarwood is also popular for indoor uses such as furniture, cabinets, and paneling because of its lovely scent and resistance to rot and pests. Unfortunately, this wood also has a tendency to split. I have seen it split after only a few months in storage. 

So why does cedar wood split?

The simple answer is that cedar wood splits when the moisture in it evaporates faster than it can be replaced. This causes “rapid” contraction, which leads to cracking and splitting.

You’ll usually see long, jagged cracks running along the wood grain when it splits. The cracks may start small but will quickly grow larger. In some cases, the wood may even break into pieces if left unattended.

The 10 Most Common Causes of Cedar Splitting

Now that we know why cedar splits, let’s explore the most common causes.

1. Exposure to Prolonged Sunlight

If you have cedar furniture or siding exposed to direct sunlight for more than four hours a day, it will eventually start to split. The heat from the sun dries out the wood, causing the cells to collapse and the wood to split.

I had this happen to me once when I left a cedar chest outside in the sun for too long. The whole top of the chest split, and I had to do a lot of work to put it back together.

How To Prevent

To prevent this from happening, apply a UV-resistant finish to any cedarwood that will be exposed to direct sunlight. You can also move the wood to a shady location if possible. If the damage is already done, use wood glue and a couple of clamps to fix the cracks.

However, providing shade does not mean you can leave your wood unsealed. The heat will still cause the wood to dry out over time, so applying a PEG protects the wood from heat and moisture.

2. Exposure to Prolonged Heat

Cedarwood should also be protected from prolonged exposure to heat sources such as fireplaces, wood stoves, and radiator pipes. The intense heat will cause the water in the cells to evaporate, leading to warping and cracking.

How To Prevent

Always use a heat guard when exposing cedarwood to intense heat to prevent heat damage. If possible, you can also try moving the wood away from the heat source, or moving the heat source away from the cedarwood.

3. Exposure to Prolonged Cold

Cedarwood is also susceptible to damage from prolonged exposure to cold temperatures. When the temperature drops below freezing, the wood contracts because of the moisture difference between the wood and air.

This is why it’s important never to store cedarwood outside in the winter. If you have cedar furniture or siding, bring it inside before the first frost.

How To Prevent

If you do happen to store cedarwood in a cold location, make sure to apply a heavy coat of wax before bringing it inside. This will help protect the wood from moisture and prevent it from splitting.

4. Excessive Moisture

Too much moisture is one of the most common causes of cedar splitting. When the wood absorbs too much water, the cells will expand and contract as it loses the water. This movement causes cracks that can be a big issue.

This can happen if you live in a humid climate or don’t properly seal your cedarwood furniture or siding. Water can also seep into the wood if stored in a damp location such as a basement or garage.

How To Prevent

The best way to fix this problem is to make sure your cedarwood is properly sealed. This will help protect it from moisture and prevent the cells from expanding and contracting.

If you live in a humid climate, you may also want to consider using a dehumidifier in your home. This will help keep the air dry and prevent your cedarwood from absorbing too much moisture.

5. Improper Storage

If you store cedarwood without much care, it can split and crack. For example, if you store cedarwood in an attic or garage, the fluctuations in temperature and humidity can cause the wood to expand and contract, leading to cracks.

How To Prevent

To fix this problem, make sure to store cedarwood in a cool, dry location. You should also avoid storing it near heat sources or near windows and skylights. If your storage space tends to get very humid, consider getting a dehumidifier to prevent any issues. 

6. Improper Fastening

Let’s say you want to attach two pieces of cedarwood using screws or nails. If you don’t use the proper fasteners, the wood may split.

For example, if you use screws that are too long, they will protrude through the other side of the wood and cause it to split. Or, if you use nails that are too thick, they may end up splitting the wood.

How To Prevent

To prevent this from happening, use the proper fasteners for your project. For example, if you’re attaching two pieces of cedarwood, use screws that are long enough to go through both pieces without protruding.

You should also use nails that are the proper size for the thickness of the wood. If you’re unsure what size to use, ask a hardware store employee for help.

7. Applying Too Much Pressure

If you apply too much pressure to cedarwood, it can cause splitting. For example, the wood can split if you hammer a nail into a cedarwood and hit it too hard. This is also a common problem when sanding or carving cedarwood. If you clamp it too hard, it can crack.

How To Prevent

To prevent this from happening, use the proper amount of pressure when working with cedarwood. When hammering a nail, for example, hold it at a 45-degree angle and tap it lightly with the hammer.

When sanding or carving cedarwood, apply enough pressure to remove the material. If you’re unsure how much pressure to use, have an experienced friend help you with the project.

8. Using the Wrong Tools

If you use the wrong tools when working with cedarwood, it can cause the wood to split. For example, using a saw with big teeth can split wood. Chiseling is also another big issue with cedar wood. If you are not careful, you might end up with a split. 

How To Prevent

To prevent this from happening, use the proper tools for your project. This includes choosing the right saw blade and using a chisel that’s the appropriate size for your project. If you’re unsure which tools to use, ask a hardware store employee or look it up online.

9. The Impact of a Hard Object

Cedar wood does not take impact very well. So dropping a heavy object on cedarwood will likely crack or split the wood. Also, if you hammer a nail into cedarwood and miss, the impact can split your wood.

How To Prevent

To prevent this from happening, make sure to handle cedarwood carefully. When carrying it, hold it close to your body, so it doesn’t swing and hit something. And when working with nails or other tools, be careful not to miss and hit the wood.

10. Dry Rot

Dry rot is a type of fungus that can cause splitting in any kind of wood. This fungus typically grows in damp conditions, often in basements or garages. If this stuff gets into your wood, you’ll lose structural integrity and have a higher chance of splitting. That’s why you want to prevent dry rot in the first place.

How To Prevent

Avoiding moisture and water is the best way to prevent wood rot. If you’re storing it in a basement or garage, put it on a shelf or in a container so it doesn’t get wet. You should also avoid using cedarwood in damp areas, such as near a pool or in a bathroom.

If you think cedarwood has dry rot, you can treat it with a fungicide. This chemical is available at most hardware stores.

Final Thoughts

Cedarwood is a beautiful and durable material that can be used for various projects. However, it’s important to take the proper precautions to prevent it from splitting. By following the tips above, you can avoid cedarwood splitting. And if you do split the wood, you can usually fix it with a bit of glue, clamps, and a truckload of patience.

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