Ipe vs. Black Locust

Posted June 14th, 2013 in Exotic Hardwoods, ipe, review, wood by ipemadeira

Black locust is rising as a potential substitute for ipe in commercial applications. This is a pretty big deal, since ipe has long enjoyed the title of “world’s best decking material”. It stands to reason that black locust must have some impressive specs if it’s being considered for major city boardwalks. Let’s take a look.

Black locust has a janka hardness rating of 1700. Not too shabby, but that’s still less than half of ipe’s rating. In fact, if you judge based purely on which wood boasts the highest numbers, ipe’s going to win every time.

So what does black locust have going for it? The big thing is that it’s a domestic hardwood, so it doesn’t have to be imported. This not only saves resources involved in transporting the lumber, it also helps to preserve tropical forests (or so environmentalist groups would have you believe–more on that in a later post). A domestic source is also cheaper for consumers than an exotic one, although the exact price can vary based on region.

Thus far, as long as you don’t mind sacrificing some structural performance, black locust seems like an acceptable alternative to ipe. However, the facts don’t stop there. Let’s take a look at availability. Black locust trees themselves are plentiful enough, but not all of them are suitable for making deck boards. Small trees produce narrow boards full of knots, and larger trees have been reported to have hollows inside them.

Finally, you have to look at how the material performs in the real world. Black locust doesn’t have the greatest track record. Proponents will tell you to be very careful when drying or acclimating the wood. In practice, this means that black locust is extremely susceptible to warping and checking.

Black Locust Warping

Think about it. Black locust is being pushed as a replacement for ipe on major public works projects like boardwalks. Literally millions of people will walk, run, work, and play on these surfaces–do you really want to use anything weaker than the most proven material in the world?

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