After a recent chapter meeting of our local chapter of CFI, a colleague of mine, Mark Violand of Inspections, Corrections and Repairs, was describing a situation he had encountered where lauan had been used. Of course, we all understand the reasons why this type of underlayment is not recommended by manufacturers, but as Mark gave more in depth information, everyone at the table started to ask questions.

Comments like "I've never seen that before" and "Are you sure that's what happened?" were followed by "I've got to see this." The following information is presented to you in an effort to educate and enlighten your better sense of judgment. This is a residential vinyl job where an existing vinyl was first covered with lauan underlayment prior to the installation of a new paper/felt/mineral backed vinyl floorcovering. On the second day of installation, the job was stopped due to the underlayment warping and heaving itself off the old vinyl floorcovering. We always seem to show the effect but this time you get to see the cause.

The lauan panels were easily removed leaving the fasteners in place. Photos 1, 2, 4 and 5 show the old vinyl (subfloor) with the fasteners still in the surface. Photo 6 shows the backside of the lauan after it had been removed. Do the photos indicate a manufacturing, installation or in-service (site related) condition? See if :

You can Make the Call!

Photo 3 shows the degree/level of penetration the fasteners had into the lauan underlayment. Photos 7 & 8 show just how far the 7/8-inch staple went into the lauan.

It measured out at just pass the half way mark. So the fasteners were half way through the lauan. But what else is not quite right about these photographs?

Where's the patch? "What patch?" was the answer I got! There was no patch used at underlayment seams or in the field. So what causes do we see so far? We see fasteners so deeply recessed that they have gone through the top layer, and into the core. We see spacing of the field fasteners on or about 6 inches on center. Sure the underlayment seams got 1 fastener per inch, but the field of the panel should have been 4 inches on center, and no patch.

So what caused the lauan to buckle, heave and warp? Moisture! That's right moisture. Where did the moisture come from? The adhesive. Why did the moisture in the adhesive cause the lauan to swell and heave? Because that's what moisture does to wood. Especially the very porous, soft core of lauan. But what if a patch had been used?

Would've could've and should've used a patch.

But even if a patch had been used would that have made a successful install. We have all been asked at one time or another to make a silk purse out of a sow's ear. Or to shine on a cloudy day.

But due to the surface of the lauan being compromised by the depth of the fasteners, I don't believe any type of patch would have kept moisture out. And the moisture in the patch could very well have caused the same condition.

I would assume that a cement based patch would not wet out the lauan as much as a gypsum based patch could. But for all the wrong reasons, sub-par materials where used. All the money saved by using lauan and not patching was thrown out the window. Using recommended products that have been tested by the manufactures to work, giving you and your customer a warranted, successful and professional job is the only option we should all consider. So the next time you grab for the lauan and not the Accuply, think to yourself; "'Am I all wet for using this?" or "Am I willing to take a bath on this one?" Thanks again for your time, and thank you Mark Violand for sharing.