Comparing Pressure Treated Lumber to Other Decking Lumber
Composite decking is getting a lot of publicity lately, but it still makes up less than 25% of decking sold. For those traditionalists, for whom wood is the only proper decking choice, there are many types and species from which they can choose. Let's look at the pros and cons of each:
Cedar and redwood
Made from a renewable resource, they are light weight, easy to work, naturally resistant to rot, decay and insects and have a tight-grained, naturally attractive appearance.
Due to the tannic acids in cedar, stainless steel fasteners are recommended. Both should be stained or sealed at least every two years if you don't want the surface to go gray. They can be difficult to find in some parts of the country and cost considerably more than pressure treated. Depending on the sapwood/heartwood ratio the decking may need replacement in as little as 10 years.
More info: http://www.wrcla.org/; http://www.calredwood.org/
Tropical hardwoods (Ipe, Mahogany, others)
Ipe is a clear winner, aesthetically. Very tight grain and few, any knots. Extremely durable.
Very hard to work; pre-drilling required to fasten. 4-6X or more the cost of pressure treated lumber. The many varieties of mahogany require very careful shopping, as the attributes and drawbacks vary widely depending on the exact species. More info: Aljoma decking and fencing.
Pressure treated lumber
At less than half the cost of cedar or redwood, and a fraction of the cost of tropical hardwoods, it's far and away the economical choice. With the newest micronized copper treatments, such as ProWood Micro CA, a lifetime limited warranty comes with a bonus of a lighter, fresher appearance and a compatibility with fasteners that rivals untreated wood. Available in various color tints. Widely obtainable.
Cons: Although it will be perfectly serviceable for decades you may not like how it looks after a few years if you don't seal it at least every other year. More info: ProWood pressure-treated lumber.