There is nothing like natural wood to make outdoor spaces look vibrant and fresh. Wood looks particularly good on gazebos, garden furniture, and bridges. Alas! Wood also attracts fungi and insects, causing it to rot.
Some woods are more prone to rot. You can take the natural path by choosing those woods that are less prone to rot for your wood projects to last many years to come. If you want your outdoor wood to resist insects, weather, and fungi, then you also need to treat it with certain chemicals.
Most Rot-Resistant Woods
Here is a list of the most rot-resistant woods that you can find. They are dense, hard, and have tightly woven fibers that make the wood resistant to water. The result is rot-resistant wood that you can use outdoors without fear that your wood will deteriorate fast. Although these varieties of wood are more expensive, they turn out to be cost-effective in the long run thanks to their long life.
An all-time favorite, teak sapwood has a rich honey-gold color and tight fibers that keep water out, thereby resisting rot. Another reason for teak’s high resistance to rot is the natural oils it secretes that keep insects at bay. Teak can be rough on tool blades, and therefore difficult to work with. The high price of teak also serves as a deterrent from using it freely.
This wood is reddish-brown and it darkens with age. A special feature of mahogany is that it exhibits “chatoyancy,” a three-dimensional, iridescent appearance when cut in a particular way. The degree of rot resistance of mahogany varies according to the growing conditions of the trees. You will find this wood to be very durable and versatile for all of your woodworking projects. However, this variety of wood is also quite costly.
Spanish cedar has the appearance of mahogany with a reddish-brown color. The wood secretes natural oils through pockets that keep insects at bay and make it water-resistant. Spanish cedar has a low density and is a soft wood, which reduces its strength.
The light brown color makes this type of oak a popular choice if you need good-looking wood. The tyloses that white oak contains create a closed-cell structure that resists moisture from seeping into the wood. The water-resistance of white oak makes it preferred by shipbuilders and homeowners who require a durable wooden finish to their interiors.
The flaming red color of redwood gives it a good reputation. The level of rot resistance of this wood depends on the age of the tree. Older trees tend to be more durable than younger ones. But a drawback of the older trees is that there is a tendency for cracking, and that can allow moisture to enter, thus causing rot. The solution here is to apply a suitable sealant or apply oil regularly to the wood.
Cypress comes in an extremely light shade of brown that is almost white. It may show patches of darker brown. Like redwood, cypress also varies in its level of rot resistance according to the age of the trees, the older ones being the most durable. Applying a water-repellent sealer can add to the water resistance of this wood.
Composites are a class of material that combines wood and synthetic materials and the resultant material looks like wood. Wood/plastic composites (WPC), for instance, contain wood fiber, sawdust, and thermoplastic resins. Some of these composites contain recycled material, but whatever the case, they are all rotproof.
WPCs are devoid of defects and are not prone to compression. However, the low density and high expansion and contraction rates can cause problems. Also, they lack a high mechanical strength. But, the main advantage of WPCs is their complete resistance to rot. WPCs are much cheaper than natural wood, so they are fast gaining popularity today as a durable and cost-effective option to regular wood.
Reasons for Wood Rot
To prevent rot from occurring in the first place, you need to understand why rot occurs. Once you know why it happens, you will be better placed to avoid it from occurring. Let’s take a closer look at some of the primary reasons for wood rot.
The main culprit in the process of wood rot is a fungus. Insects will also gravitate towards the wood but will do so only if the wood is already wet and rotting. It is the fungi that first strike, which is followed by termites and other varieties of insects that destroy the wood.
We call the fungi that destroy wood decay fungus. Fungi are plants devoid of chlorophyll. Such organisms cannot make their food because they need chlorophyll to do this. Moisture in the wood serves as food for the chlorophyll-less fungi.
Conditions Conducive to Rot
Four conditions will enable rot to grow:
The moisture level of the wood should be at least 20% to 30% for rot to thrive. Wood being porous will soak up water. If the wood soaks up excess water, then the fungi will find it difficult to breathe and it will not survive as its oxygen supply is cut off. Using a moisture meter can help monitor wood and determine just how wet it is (just touching the surface can be misleading).
A fungus is a living organism that needs oxygen to breathe. It will only survive if the oxygen level in the air is at least 20%.
Temperature is another governing factor that allows the continued existence of fungi. Most fungi will get killed at temperatures over 130°F and will become dormant if the temperature falls below 40°F.
If the wood is suitably laden with moisture, fungi will not only use the wood as a food source but will thrive thanks to the warm temperature and moisture.
If you choose your wood carefully, you can ensure that you get wood that does not rot. The requirement for wood that does not rot depends on where you are going to locate the wood. If you need wood for indoor purposes, then you may not have to worry too much about rot.
However, even while indoors, there are certain places like the kitchen (as under the sink) and in the washroom where circumstances exist that can promote rot in wood. Therefore, you need to select your wood according to where you will be using it, and you can select some of the most rot-resistant woods that we have highlighted here for the wood that you use in your woodworking projects to last a long time.
Here are some of the most frequently asked questions about wood rot, how it occurs, and the ways to prevent it:
Q: Is wood rot reversible?
A: Once wood rot occurs, you cannot reverse it. The only remedy is to replace rotted sections of wood with new wood.
Q: How does wood rot occur?
A: The primary cause of wood rot is a fungus that thrives in the presence of moisture.
Q: How can we prevent wood rot?
A: We can prevent wood rot by keeping it away from moisture.
Q: What type of wood never rots?
A: Highly rot-resistant woods include cedar, redwood, and cypress. We use them in moisture-prone areas like decks and saunas. They produce natural chemicals that prevent the wood from rotting.