When it comes to color-matching, Composite Decking wins. However, when we look at arguably more significant issues such as hardness, fire ratings, heat, and slip resistance, Exotic Hardwoods come out on top. So far, we’re looking at Composite Decking with a score of 1 versus Exotic Hardwood Decking with a score of 4. Let’s explore a few more characteristics, and of course, we’ll continue keeping score.
Exotic Hardwood Decking Is a Strong Contender
Let’s start with a caveat: Not all Composite Decking products are created equal; they’ll vary by manufacturer. And the latest technology is definitely allowing these products to gain when it comes to the strength department. However, it’s still a bit of a gamble. By contrast, real lumber species have predictable strength, based on species. (In fact, Ipe boardwalks are probably overbuilt.)
One way to gauge the predicted strength of a Composite Decking product is by taking a look at the recommended joist spacing; most will suggest a 12-inch center (as opposed to 16-inch centers). The recommendations are just that, but they’re designed to allow for little to no bounce — something that becomes even more important with the higher the volume of traffic you expect on your decking surface. So again, this issue is even more significant for a public dock or boardwalk.
When it comes to strength, the plastic component of Composite Decking products again bears consideration. First, the “memory” of plastic means that once deformed, it simply won’t regain its original form. Second, the wood flour core of Composite Decking lacks structure and strength of its own, causing it to rely heavily on its plastic outer shell. If the strength of the outer shell is reduced, the overall strength of the Composite Decking board is severely weakened.
Score Update: Composite Decking=1, Exotic Hardwood Decking=5
Exotic Hardwood Decking Withstands Moisture
Early Composite Decking products were made from more homogenous mixtures of wood flour combined with polyethylene or PVC; the mixture was then extruded into boards. However, since the wood flour still absorbed moisture (just as intact lumber does), mold issues were the unfortunate but unavoidable result. The related deluge of class action lawsuits motivated a change in composition: today’s Composite Decking is made with a wood flour core surrounded by a plastic “cap stock” to protect the wood flour core.
While the shift in manufacturing solved one issue, it also served to create a new — and arguably more significant — one. Now the outer plastic shell can easily become cracked or separated from the core as it responds to temperature fluctuations and use. (Remember, plastic has a memory and won’t return to its original shape once it has been deformed, and it easily can be deformed in response to heat and other elements.) The cap stock is also quite thin and can easily be punctured, exposing the wood flour core. (Of course, puncturing necessarily occurs during installation.)
Although Exotic Hardwood Decking boards certainly absorb moisture as well, they retain the complex natural structures by which the tree absorbed nutrients for the tree. With those cellular structures intact, along with resins inherent in Tropical Hardwood lumber species, decking boards are protected from damage by both mold and insects. Such is not the case for Composite Decking boards. In fact, without those natural structures intact, the broken down structures actually serve to encourage mold growth.
Score Update: Composite Decking=1, Exotic Hardwood Decking=6
Continue with Part 4.
Learn More About the Lumber Industry
J. Gibson McIlvain Company
The McIlvain family has been immersed in the premium import & domestic lumber industry since 1798. Headquartered just outside of Baltimore, the J. Gibson McIlvain Company is one of the largest U.S. importers of exotic woods. As an active supporter of sustainable lumber practices, the J. Gibson McIlvain Company has provided fine lumber for high profile construction projects worldwide. Call (800) 638-9100 to speak with a J. Gibson McIlvain representative.