The house we just bought has an old, partially rotted wood deck at the rear yard that we want to remove and replace with a new one.  Although the deck is redwood, it is only 12 years old, and many of the deck boards are twisted and bowed.  Are there any other materials that we can use instead of redwood?  Someone suggested that we use pressure treated lumber or go with a hardwood like mahogany.  Any suggestions?

B. L., Richmond

Redwood is by far the most common decking material on the west coast because of its natural decay resistance, beauty and affordability.  However, if it is not properly installed and maintained, it will deteriorate.  Your letter did not go into detail about the installation of the deck, but if many of the deck boards are twisted and bowed, it was probably not installed or fastened correctly. 

To answer your question about other types of materials for decks, there are actually several options for the home owner and contractor.  Besides pressure treated lumber and select hardwoods, there is also plastic, vinyl and wood-plastic composites. 

Pressure treated lumber is most commonly used for deck supports, girders and joists.  The advantage of this material is its excellent ability to resist rot; it is even designed to have direct contact with the earth. One of the disadvantages of this wood is that it tends to crack and split, leaving splinters and a rough surface.  Sometimes these boards also tend to twist and bow, which can affect the aesthetics of the deck surface.  Painting and staining can prevent some of the cracking and splitting, but it must be done on a routine basis to keep the deck looking good.

Besides using pressure treated wood or redwood, you could also consider the use of tropical hardwoods.  Tropical hardwoods (commonly a type of mahogany or teak) have rich colors, are naturally decay resistive, and have a high density.  They are also more expensive than either redwood or pressure treated wood, and require more care and skill in the installation.  For example, if nailing the boards by hand, they usually have to be predrilled.  These decks also require more maintenance than other decks because the surface of the boards must be coated regularly with a water repellant to prevent the boards from splitting and turning grey. 

A new alternative to wood decking is synthetic decking, decking material made from recycled plastics and wood fibers.  These materials look and feel like real wood, and are a little more expensive than redwood.  However, they have several advantages.  These boards are impervious to moisture and will not split, crack, warp or rot.  They can be worked with standard tools, and do not require staining or sealing