Woods that Don't Tolerate Exterior Wood Sealer Woods that Don't Tolerate Exterior Wood Sealer
While a wood sealer sounds like a must for any outdoor wooden structure, it may not be tolerated well by all types of wood. Some types of wood can actually be damaged by trying to use a weather-proof sealant.
While teak can be sealed, it's usually suggested that you don't. Teak has natural oils that permeate through the wood. It's naturally water resistant, and with proper care it can resist mold and mildew. If you must seal teak, you need to allow it to weather for a few weeks beforehand. This will allow a lot of the oils to naturally come up. The wood should be washed well, and only sealers that are designed to be used with teak should be considered.
Composite wood is popular to use outdoors since it will resist rot and is low maintenance. Even with this, many people will try to seal it. Composite wood is not made of solid logs, and as a result it can not accept the sealer. It can be painted, and some can be stained with some work, but sealing it is just a waste of money.