Wood is the traditional material used for deck construction. Even today nearly all decks use pressure treated wood for the deck frame. Pressure treated decking is still used for decking and railing for cost conscious builders. Cedar is a popular choice for decking and railings because it is naturally resistant to rot and decay, it is readily available, and is attractive. Redwood was very popular in the past but is now difficult to find outside of California, Washington, and Oregon. Exotic woods have become popular in recent years because of their beautiful lustrous colors. However exotic woods such as Ipe are very expensive, difficult to work with, and are harvested from the rainforest.
Thermally modified wood is a process that creates lumber that will not rot or decay naturally by applying heat without the use of chemicals. The material is affordable, easy to work with, attractive, and comes with a limited warranty.
All wood materials used for railings and decking will need to be maintained to prevent cracking and graying. Use an oil based stain to protect the wood from drying out to quickly. You can also clean and brighten your deck using products designed to restore the color of your deck. At the very minimum you should try to keep your deck clean by washing it off with a power washer or hose a few times each year.
Because wood is a natural product a certain percentage may contain imperfections or defects such as knots or warping. You should sort through your lumber and return defective material. The higher the grade the material the better quality. The most common material is #2. Select grade offers fewer knots and a straighter board. Look for stamps and tags to identify the species and grade.
Common deck materials are available in different lengths for 6x6 and 4x4 for support posts and rail posts, 2x10 and 2x8 for joists and beams, 2x12 for stair stringers, 5/4x6 or 2x6 for decking, 2x4 and 2x6 for rail parts, 2x2's for rail balusters, and 1x12 for fascia.