Pressure Treating Wood is an interesting process that has been developed and change over centuries. In order to pressure treat wood they load it into pressure cylinders. The wood is subjected to high pressure and vacuum cycles to force the penetration of the chemical mixture, and then extract the excess. The result is in a more resilient wood than it would have otherwise been, but generally not as resilient as Western Red Cedar.
The reason for this is that most of the wood that is pressure treated is Hem-Fir. It is classification of wood that includes both Western Hemlock and Amabilis Fir. These are good building materials, but do poorly if left outdoors untreated. Hem-Fir is very common, and grows well in most of British Columbia’s climates. However, it does not have the natural tendency to resist decay like Western Red Cedar. As a result, it is relativity cheap. With the addition of pressure treatment process it becomes more resistant to rot. It is prime candidate for pressure treating because takes the pressure treatment well, as a result of its high water content. This comes with some common problems. Checking, twisting and bending. This all occurs primarily as a result of the dry process, and is exacerbated by rapid drying.
It can be mitigated by reducing the speed in which it dries, such as having in under cover or a tarp. Or by having it attached to a structure such as fence. Having it attached in a structure will often keep it from going wonky because it is in a braced position. However it will not reduce the checking. As I have talked about in another blog post, checking is a natural occurrence for wood. It isn’t a result of any kind of defective product.
In conclusion, Western Red Cedar is certainly the more expensive of the two options. However, most consider it having a noticeable longevity over pressure treated on top of the preferred visual appearance. When it comes to a utilitarian approach pressure treated is definitely a serious option, especially if price is a large factor. However, if you are looking for more of a natural and refined look cedar is most likely the way to go for you. If the colour of pressure treated it doesn’t quite suit your taste you can always stain it with a large variety of stains to either maintain the natural look or to alter it to your stylistic taste. You may be surprised how a nice stain can protect and maintain the natural look of the wood. You can come in to our store and we can help and show you the many options or you can read a future blog post about what is the difference between all of our stains.