Laminate Flooring Installation Problems: Gapped End Joints + More

laminate flooring gapped joints | @GlennRevere

You finally bought your new laminate flooring! Congratulations! But remember, installing your new floor correctly is as important as — and maybe even more important than — the selection and purchase. You are paying cold, hard cash for that floor and expect the best. The installation should also be “the best.”

As a Certified Flooring Inspector, I see so many beautiful floors that have been “messed up” because of sloppy installation procedures. Every box of flooring contains detailed installation instructions. With the proper tools and a little training, it should be relatively easy to install laminate flooring. This is a do-it-yourself floor. You’d think professional installers would do it right every time. Well, don’t bet on it.

A major manufacturer of laminate and engineered wood flooring commissioned me to look at a complaint for them. The complaint was “planks loose and coming up in corners.” I made an appointment with the homeowner to inspect the floor.

The material was installed in a room that had been a back porch with a raised foundation. The porch had been enclosed and converted to a small family room. A small fireplace warmed the room. There were gaps between several of the boards. I also found a board with a high corner. I have copied the body of my inspection report here in order to show you the highlights of my findings:

Mrs. XXX stated that the family room was originally an enclosed porch. The dirt (no plastic cover) crawl space under the concrete subfloor has no access or ventilation. She said the installers used 4 bags of leveler on the subfloor prior to installation.

Claim History
Mrs. XXX stated they noticed the fractured board and proud corner immediately. The installer returned and said that the entire floor would have to be pulled up to do the repairs. The gapped end joints appeared a few weeks later.

I found 3 end joint gaps in the walkway between the back door and the kitchen entry. I found a proud corner adjacent to a board with a fractured end. I did not see any weighted deflection (trampolining).

Field Tests
End joint stagger varies from 8 1/4″- 10 1/2″. Where perimeter access is available, I measured perimeter gaps at 3/8”-1/4″. I measured 3 end joint gaps between .013″-.016″. The proud corner measures .023″. The floor is flat lengthwise to 1/16″ over a 10’ radius. It is out of flat 9/32″ over a 10’ radius widthwise. I used a 30X lighted scope to determine that the observed fractures are topical.

Manufacturer Instructions/Industry References
The manufacturer requires that the subfloor be flat to 3/16″ over a 10’ radius. Joints must be tight. Boards with visible defects must be culled before installation.

The severely out of flat subfloor does not give proper support for this floating installation. That is the cause of the end joint gaps. The visibly fractured board and the board with the proud corner should have been culled. Otherwise, these conditions are site related.

Glenn Revere IICRC #113098

So there you have it. The subfloor must be flat and smooth to the manufacturer’s tolerance for any type of hard surface flooring. This installation information is always included with the material. If it is missing, it is easy to get. One can call the retailer, distributor, or manufacturer. The manufacturer’s website also has the installation requirements. Ignorance is NO excuse.


Who is Glenn Revere?

Glenn Revere has been a carpet expert since 1973. He’s a certified flooring inspector and the author of All About Carpets, the only book written to protect and inform you about your carpet choices, from carpet buying and carpet warranties to carpet care and maintenance. You can find him on Facebook, Google+ and Twitter.

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