Merbau wood is great to use for decking timber. Tough, durable and visually appealing, it has become a favourite of builders and homeowners. But it has one particularly annoying quality; merbau timber “bleeds” which can stain surrounding structures.
The problem is that Merbau (and many other timber species) tend to discharge sap and tannins. There are no worries when the deck is built directly on top of the soil, because the discharge is simply absorbed into the ground. But if the deck, screen or fence is built atop concrete, for example, the oils and resins that leach out may leave ugly stains on the surrounding concrete. These Merbau wood stains can also affect furniture, clothing and other materials that come in contact with the timber.
The discharge itself is harmless. It’s just ugly. There are a couple of ways to deal with Merbau wood stains.
First, you can avoid the discharge by ensuring that the timber is thoroughly dried up even before you start building with it. To do this you have a couple of options. First is you let time and nature take its course and wait it out while the tannins completely drain out of the timber. The good news is that the tannin inside the timber is not infinite so it will run out eventually. But this could take a few months.
Or you can force the tannins out using a pressure wash or even with a commercial product such as a deck cleaner. This significantly cuts down the time needed to flush out the tannins.
If you have already built your structure and installed the Merbau timber and it still leaches tannins, then you will need to deal with the resulting stains directly. Again, you have two options. The first also involves time and nature — simply ignore the stains and they will eventually fade away. Eventually.
Or simply buy yourself some bleach, the type you probably have and use in your home already, and a stiff brush. Then apply some elbow grease and scrub away at the Merbau wood stains. They should be erased from existence soon enough.