Does Wood Rot In Salt Water?

Does wood rot in salt water?

Wood is a natural material that will eventually degrade and go back to the earth. Although the length of time wood takes to fully decompose will depend on several factors and in some cases, it can take upwards of a century!

When you’re building a wooden structure along the coast, there is no getting away from the fact that it’s going to go through some battering since the elements in these areas are far from forgiving. But one thing that worries a lot of people is that the rotting process for wood will be sped up when it is exposed to the sea. But does wood rot in salt water?

When salt water gets into wood, the salt particles will remain long after the moisture has dried up. These particles can prevent the natural expansion and contraction of the wood, breaking apart the fibres and causing it to deteriorate more quickly

But that shouldn’t put you off using wood in coastal areas or where it may be heavily exposed to salt water. By using the correct treatments, you can still get a good lifespan out of wooden products regardless of their contact with salt.

How Does Salt Water Affect Wood?

It is clear by now that salt water will speed up the decomposition of wood. If you are using timber to build a coastal structure then you also have to consider the fact that the UV rays from the sun will also play a part in the deterioration of the wood. As this happens, cracks will form and these will soon become filled with salt as well as allowing moisture to soak through. Once this starts to happen, rot won’t be far behind.

However, you should keep in mind that the speed at which the wood deteriorates will be based on how much contact it has with the salt water. Things like decks that protrude over the water and boat docks are much more at risk than a coastal house that may occasionally be splashed by a large wave.

Wood is very absorbent and will wick the sea water inside. Once the moisture dries up, crystals of salt are left behind and these gradually push the wood fibres apart. But you don’t need to be too concerned about this since even with this type of exposure, you can still expect deterioration to take up to 30 years to become problematic.

How Can I Protect Wood From Salt Water?

30 years sounds like a long time but when you’re talking about a structure degrading, time can pass pretty quickly. While it is possible to replace panels and refresh the structure, prevention is better than cure!

When you are building with wood in coastal areas, especially right on the water, you will need to make sure that you use a treatment that offers protection against both water and UV damage. These treatments will stop the wood from splitting when exposed to the sun and will ensure protection against the effects of seawater. But even when you have applied these treatments, it is still essential to keep an eye on the condition of the wood to make sure you don’t miss any signs of degradation. The sooner you deal with problems, the less work you’ll have to do.

There are lots of different wood treatments to choose from and this can make it difficult to know what to use. When it comes to salt water, you’ll want to look for something oil based or creosote.

However, there is an alternative which involves far less maintenance and will put your mind at ease over the coming years. Composite timber is much more resistant to the elements including sea water and UV rays. But you don’t have to sacrifice appearance as you still get that beautiful, natural wood look.

Composite timber is also incredibly durable so it’s ideal for constructing things like coastal homes, decks and docks. It is also possible to buy aluminium cladding but this doesn’t have the same aesthetic appeal.

How Were Wooden Boats Protected From Salt Water?

Think back to days gone by and there were hundreds of sailing vessels that were made from wood. For example, in Viking times or when pirates sailed the seven seas, they were pretty limited on what they could build with and wood was a go-to option.

But since the wood will deteriorate quickly when it isn’t treated, how did these boats not fall apart after a couple of years? The secret was pitch waterproofing or tar which was extremely common and helped boats to last much longer.

This method ensured that the vessel was water resistant and involved putting tar into the boat’s hull. This created a seal between the wooden panels used to make the ship and made sure that water couldn’t get in.

Does Salt Water Preserve Wood?

We have been looking at the ways in which salt water can cause damage to wood but there is a flip side to all this and it feels very contradictory.

If you leave the wood in regular water, this will speed up the process of deterioration. However, if the wood is submerged in salt water, this almost acts as a protector against the organisms that break down wood. So, in theory, the wood would have a longer lifespan.

That said, if you were to build a boat out of wood and leave it in the ocean, you’re still going to have to replace panels over the course of time as no amount of moisture is ever going to do the wood any favours.

What’s more, when the wood is constantly exposed to water and then dries out again, you’ll find that fungal problems are common. But since fungi cannot grow in salt water, this won’t be an issue when creating coastal structures.


There may be a few occasions that salt water is good for wood but by and large, it’s not going to do it any favours. In fact, as salt and moisture get into cracks in the wood, this speeds up the degradation process and any wooden structures affected by this will need maintenance much sooner than anything else.

So when you ask does wood rot in salt water, the answer is yes. Wood will rot in any type of water but much more quickly when it’s salty. The best way to prevent problems from occurring sooner rather than later is to use an appropriate wood treatment.

Does Wood Rot In Salt Water?

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