For years the default material used for decks and most porches has been pressure treated pine. It is readily available at any big box home repair store as well as any building supply. Virtually all non custom houses have decks built with PT pine. It is a cost efficient material, but has it’s issues.
All deck materials should be sealed to lengthen their lifespan. Treated pine, especially in the more sunny areas, even when sealed will misbehave more than any other wood. We have all seen the buckled handrails, splits, twists, cracking and overall instability. Not to mention the splinters!
Of course, we are talking about the horizontal surfaces. In general, the vertical application of PT pine, at least as it pertains to decks, is not so bad. You will still see some warping in the rail designs. That can usually be offset by carefully choosing the pieces that will be used, trying to eliminate any that are showing early signs of bowing. And, as the only real option, at least cost wise, for the actual frame of the deck, PT pine is a winner.
Other options for decking include more expensive woods such as cedar or redwood. You can find comparisons on Consumer Reports regarding these woods as well as the more exotic rain forest woods such as ipe (pronounced e pay).There are still more options including metal, plastic and the relatively recent development of composites which are generally speaking, a blend of plastics and wood products and are also more expensive.
Oddly, though, one of the most durable, long lasting, rot resistant, bug resistant and beautiful woods is left out of the mix! Cypress! It could be that cypress is not readily available in all parts of North America, but neither are the exotic woods imported from South America.
One could go on and on about the virtues of cypress. Deck builders South Shore MA It has been used for boat building for centuries. It has been used for head”stones” in cemeteries! Though you probably won’t be able to read the inscriptions, you will find these wooden grave markers in older cemeteries in coastal locations around the South. They are usually well over 100 years old! Do your own search for cypress and be astounded!
Cypress grows in swamps and wet areas. It is acclimated to harsh conditions from birth. The product that results after milling is smooth and stable. Most of what would be used for deck flooring is already pressure treated in addition to the natural preservatives already in the wood. If left alone, it would weather to a light gray color. Like all decking material, however, it is not maintenance free if you want it to last as long as possible. It is recommended that it be sealed with a penetrating sealer the same as other woods.