Category: Interesting

Lauan plywood is a controversial flooring underlay.

I went with 5.2mm lauan plywood from my local Home Depot with a recent flooring project because it seemed like the “obvious” choice. It’s recommended all over the internet on seemingly reputable sites, the University of Massachusetts recommends it, a major tile manufacturer recommends it, and my Home Depot Home Improvement 1-2-3 book recommends it.

However, after going through six and a half pounds of 6d 2″ ring shank nails and hours upon hours of work with my wife, I found some web sites highly critical of lauan.

Some allege that lauan board is inferior to regular plywood for various reasons, including inability to resist indentation, hygroscopic properties, oils in the wood, and so on. This is generally the opinion taken by an author for Floor Covering International.

I freaked out. We were in the middle of a major weekend project, we had no time for major problems, and going back would be a giant setback.

To add insult to injury, when we were finally ready to apply the tiles, we found instructions inside the box. The very first line of instruction read, “Do not use mahogany plywood.” AAAUUGGHH!!! (While technically incorrect, “mahogany plywood” commonly refers to lauan.)

We went ahead and finished the project as is because we had no better alternative.

Since then, I’ve calmed down. My experience working with the wood and further thinking suggests:

1. Lauan plywood resists dings well. It took a solid, direct hammer blow to dent it, and those blows didn’t dent it too badly.
2. Running our refrigerator over some bare lauan didn’t do a thing to it.
3. The criticisms of lauan aren’t objective, nor are they quantitative. They appear to be both communally reinforced and based on fuzzy memories. I also suspect that confirmation bias may influence these detractors to blame lauan for bad projects that may have been affected by other factors, such as bad installation practices.
4. The only lauan in the plywood is actually an extremely thin top surface. As far as I could tell, the rest of the plywood is regular wood you might find anywhere.
5. Lauan is used in boatmaking because of its water resistant properties.
6. We primed the wood. While this isn’t a sealer per se, it should act as an additional barrier, reducing any moisture-related problems.

I am not flooring expert, but the evidence suggests that lauan is actually a fine underlay choice as long as you get the right quality.

The only valid criticism might be that lauan is a tropical wood and its use may contribute to tropical deforestation. However, even then, there are lauan tree farms, so this might be able to be managed?