Engineered Flooring Requirements

Over the past decade there has been huge controversy over engineered vs. solid wood flooring. Engineered flooring was designed to be more dimensional stable than solid under certain conditions. Most manufacturers have found by maintaining proper relative humidity (typically between 35 to 55%) engineered flooring remains reasonably stable where solid flooring will see side affects like gapping. Engineered will also see side affects but at lesser amounts.

If engineered flooring is exposed to high or low RH conditions one may see irreversible affects like checking, splitting, shear, delamination, dry cupping, etc. When environmental conditions go beyond the caution zone and into the guaranteed to fail zone these side effects will become permanent. Where solid wood flooring will see side affects as well but usually will just have larger gaps between the planks.

Listed below is a chart which helps outline some of the relative humidity boundaries by the flooring manufacturers. Retailers should educate their clients in pre-sale regarding proper relative humidity requirements and the possibility of the effects in the “Guaranteed to Fail” zone.

To download the factory finished performance document click here.

Floor Inspectors Guild of North America

I recently attended the Guild to learn more about engineered construction flooring materials.  Professor Hindman and Professor Loferski from Virginia Tech along with Professor Phil Mitchell with N. Carolina State University led the course.  The course was attended by leading inspectors and manufacturers around the country.  The professors broke down the subject matter(s) into terms that we could understand while providing the wood science behind it.  The subjects taught in this course are listed as follows:

• Material Properties of Wood vs. Engineered Flooring
• Mechanical Properties
• Moisture Content Measurement in Engineered Wood Products
• Understanding Balanced Construction
• Failures in Engineered Flooring
• Radiant Flooring
• Testing Standards for Engineered Flooring
• Moisture in Buildings (Building Science)
• Lab work at Virginia Tech—Microscope Evaluation of Engineered Flooring, Moisture Measurements, Janka testing and bondline testing

This 3 day course provided extended knowledge of wood dynamics and how it relates to in service usage.  It is evident by the course titles they are very in-depth subjects.  One example is Dr. Loferski (as shown below) explained free vs. restrained expansion theories of engineered flooring, modulus of elasticity, advantages of microscopic cell evaluation, plus much, much more.

Cell Evaluation

Understanding Free vs. Restrained Expansion

Free expansion is the movement of solid wood, while the plys of engineered restrict expansion movement.

I give Selva Lee Tucker (course administrator) many thanks for putting this program together and bringing continuing education to another level.  For those who couldn’t make it or those who are thinking of attending the Guild, I would highly recommend the next one.  It was well worth the time and money invested. 

3M Has Found the Gold

It takes companies like 3M who strive to become leaders within the industry.  With the latest flooring and sandpaper technology, “3M Has Found the Gold”.  We’re talking about the “Easy Change Floor Sanding Discs” in various grits ranging  up to 150.

We tested the 120 grit Gold Easy Change disc backed up with the 3M thin white driver pad.  This parquet floor (photo below) was drum sanded to 120 grit in both directions.  The normal process would have included hard-plating or screening to remove drum marks.  In many cases over screening produces dish-out which does not happen using this soft-plate technique with the gold easy change discs.  As you can see in the photo below there is not one sanding mark in the floor. 

NWFC has personally tested and used this system for the past two years.  We have not used screening techniques since that period.  I highly recommend the 3M Easy Change Gold 120 grit for those who stain or finish wood floors. 

I guarantee you this system works. If you have any further questions regarding this product contact your 3M representative. 

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