Selectwood Perspectives

Exterior Siding: Wood and Composite

Wood Versus Composites on Building Exteriors

Even with the economy off there is still excitement in the building material industry. At Selectwood we are constantly being introduced to new and innovative composite materials that promise to perform better than the last generation of products. Some products are not on the market long before a better product is introduced. Our customers are always curious but do not automatically embrace new materials until the advantages are fully understood and to some degree field tested. At Selectwood we are constantly trying to evaluate the performance and environmental appropriateness of the products we choose to sell. How “Green” can many of the newer composite materials be since they are not natural or sustainable. Conclusions can be tricky and certainly subject to on going debate.

One argument for composite materials is they are “Earth Friendly” since they consume fewer trees. Some are made from recycled materials. Unfortunately evaluating materials as to what is more “green” is too complex to reach a quick conclusion. Creating plastics typically consumes more energy than harvesting trees. Plastics come from non-renewable resources whereas trees are renewable. Wood is also biodegradable so ultimately wood may turn into compost. Plastics will last forever in landfills and should ideally be recycled.

Another argument favoring composites goes that if the composite product requires two to three times less energy to maintain than its wood counterpart. The initial energy used to create the composite may be a worthwhile investment. Even though wood is natural, it typically requires nonrenewable energy to harvest, transport, manufacture and maintain.  If the composite material can be recycled at the end of its life cycle then the composite product may be the an appropriate choice especially if the maintenance over it’s like span is relatively low.

Almost all arguments relating to the use of composites focus on exterior applications. Poor construction practices including no back priming, faulty flashing techniques and moisture trapping especially during the building boom of the last twenty years have contributed to wood’s poor reputation with siding and trim. Home owners are increasingly reluctant to hire contractors or use valuable free time painting or staining a house every three to five years.

For those customers who want more authentic exterior details many of the new cellular PVC or composite materials perform extremely well outdoors. They hold a paint finish for fifteen to twenty years without blistering or peeling and require minimal prep work before a new finish is applied. Fiber cement lap siding while popular in the southern U.S. for many years due to its termite and fire resistance has now started to make serious inroads into the Northeast market. Typically fiber cement will hold a finish longer than wood siding. Most factory finished fiber cements have 15 to 20 years coating warranties. Fiber cement like wood is subject to paint failure when moisture gets trapped on the back side. Fiber cement needs proper flashing to achieve coating performance.

The good news for wood is material researchers continue to find new and exciting ways to use wood as an exterior building product. At Selectwood we have successfully sold Miratec Exterior Composite Trim for many years backed by a twenty-five year warranty. Miratec researchers discovered how to blend wood fiber with epoxies and treat the blend with Borates to create trim and sheet stock that is superior to almost all finished wood species in outdoor conditions. When it comes to composite decking, researchers at Master Mark Plastics developed a method to take waste wood saw dust blended with recycled plastic milk jugs and proprietary ingredients to create Rhino Deck. Rhino Deck continues to be the favorite “Green” composite decking at Selectwood because it is made almost entirely with recycled products.

New for Selectwood in 2009 is a beautiful wood decking called Cambia. Cambia is made from eastern Poplar which untreated is highly susceptible to rot and decay. The Cambia process turns Poplar into a stable, decay resistant exterior decking. All this is done through a heat treating process called Torrification. Without adding harmful chemicals, the Torrification process changes the woods characteristics. Torrified wood absorbs less moisture and is unaffected by microorganisms.

At Selectwood we take our role as product pioneers very seriously. Even though the role of some wood products in exterior application is shrinking, wood scientists continually come up with exciting new ways to utilize wood. We believe we are entering an era where we will be more product specific for interior and exterior applications. A properly primed and painted finger-jointed pine moulding may great for indoors but may not be a good choice for exterior use. Conversely a painted cellular PVC moulding may outperform any wood moulding outdoors but may not be cost effective for interior use. We do expect a home built with the newer composite materials to require far less maintenance than a home built just ten years ago.

One final benefit: There is no question the use of composite materials has slowed the consumption of old growth lumber for siding and trim. In Selectwood’s case we prize our inventory of old growth Western Red Cedar, Douglas Fir and Redwood. This wood is valuable and should be used in applications where it can be appreciated for its natural beauty. Today it may be easier to bring our old growth lumber indoors and not consume it in painted outdoor applications. The beauty of old growth wood should be admired and appreciated for years to come.