Mahogany is a type of wood that has been used for centuries. But these days “mahogany” is just tossed around to describe types of timber that have no relation to the true mahogany species. Currently, there are only three types of true mahogany. These three species are Honduran mahogany (Swietenia macrophylla), Cuban mahogany (Swietenia mahagoni), and Pacific Coast mahogany (Swietenia humilis).
Whenever you see the words “true mahogany,” “original mahogany,” or just “mahogany” in this article, we are referring to any of these three species as their characteristics and structure are all very similar.
Is Mahogany Naturally Waterproof?
Firstly, it is important to clear up the difference between waterproof and water-resistant. When wood is waterproof, it means that the timber will not allow water to penetrate the surface at all.
Whereas water resistance indicates that the timber will repel water for a short time but if water is allowed to sit on the surface for a prolonged amount of time it will eventually penetrate the wood.
When it comes to the waterproofness of mahogany, this timber is as good as it gets. True mahogany is pretty much completely waterproof due to having no pockets or grooves. If we compare it to other fake types of mahogany, such as the African or Philippine variety, then these are known to have a lot more pockets or grooves which make them less waterproof.
If you want to know the waterproofness of the mahogany you are dealing with, it is important to know exactly what species you are working with and if it’s the real deal.
Does Mahogany Absorb Moisture?
True mahogany has a distinctive structure that contains very little space inside its fiber vessels. This means that mahogany is so dense that it doesn’t have much space to absorb or release moisture.
So to answer the question: yes, mahogany will absorb moisture, but not enough to cause any problems. In saying this, we still do not recommend using mahogany in a wet area such as a bathroom.
Does Mahogany Rot When Wet?
To answer this question it is very important to know what sort of mahogany you are working with. This includes the species as well as the age of the tree your mahogany came from.
The reason for this is that (Swietenia) or true mahogany is much more rot-resistant than any of the fake versions. The age of the tree the timber came from will also matter for rot resistance. Older mahogany trees are much better at battling moisture than younger trees.
If we are talking about old, true mahogany timber, then no, it will not rot when wet and should be able to last externally for a very long time. But with other or younger types of mahogany, this is not the case.
Does Mahogany Expand When Wet?
As discussed above, mahogany has very little space inside its fiber vessels. This means that there isn’t much room for water absorption and also not much room for expansion or contraction. This causes humidity or temperature changes to have very little effect on the timber.
Back to the question: yes, mahogany will very slightly expand when wet, but this is nothing compared to other types of wood such as poplar, cedar, or pine.
Does Mahogany Warp When Wet?
We now know mahogany will not rot, will not expand, and absorbs very little moisture. But will mahogany warp?
The answer to this question is no. Because of the same fiber vessel structure that keeps moisture out, mahogany is also far less prone to warping. Warping is caused when the moisture content of different parts of the timber changes unevenly.
This does not happen with mahogany as there isn’t enough space for water to get into, therefore it will not warp.
How to Waterproof Mahogany Wood
If you have true mahogany timber, then there is really no need to waterproof it. Mahogany from the Swietenia gene has such a high natural waterproofing that adding any type of oil, wax, coating or paint would be a bit of a waste.
On the other hand, if you are not sure of what species of mahogany you have, or if it is even real mahogany, then it’s probably a good idea to use something to help its waterproofness.
There are quite a few different products you can use to ensure that your timber is waterproof, and they can all be applied in the same way. Here are a few product options to waterproof any type of timber:
- Linseed or tung oil
- Polyurethane
- Lacquer
- Varnish
- Stain sealant
- Stain-free sealant
All the materials above can be found at your local hardware store or building supplier. What product you use is your own preference. If you want something cheap and clear, go for polyurethane, or if you want something with some color that’s a bit more expensive, go for a stain and sealant combo.
These products can all be applied pretty much the same.
All you will need is either a clean rag or paintbrush. We recommend using a rag, as this will leave a streak-free coating. When using a paintbrush you can end up seeing the brush strokes and if this is the case you’ll have to sand the timber back and start again.
Summary
As you can see from the sections above, true mahogany is a very tough opponent when battling water. This type of timber is waterproof, rot-resistant, has very little expansion, and will not warp when wet. This is all thanks to its dense structure and the fact that it has no pockets or grooves.
When it comes to mahogany, it is also very important to make sure you are sourcing the real stuff. There are lots of so-called variants and also a lot of fake mahogany species going around. This can be confusing so be sure to check what you are purchasing.
Best of luck with your future projects using mahogany wood.