Search Articles:

How Did This Wood Floor Rise Two Inches Off the Subfloor?

By Drew Kern
February/March 2008
print  Print          Download PDF

The Problem

Recently, I was called to inspect a floor for homeowners who had just moved into a five-year-old house. After living there for six months, their dining room floor buckled approximately 2 inches off of the subfloor.

The Procedure

The floor was solid ¾-by-2¼-inch factory-finished red oak. It had been installed professionally by flooring contractors approximately three years prior. The installation was a standard staple-down over OSB. The homeowners contacted several local flooring stores and spoke to many contractors trying to find an explanation, never receiving a satisfactory answer.

The Cause

After arriving at the home and visually inspecting the floor, I noticed that the installation began tight against the existing ceramic floor in the hallway. Initially, I imagined that this inspection would be an easy case of the floor expanding with nowhere to go on the opposite wall, causing it to buckle up. However, when I removed the wall base, I found a ½-inch expansion space had been left. Okay, now further investigative techniques were needed. Why did this floor buckle three years after the initial installation? All moisture readings and humidity levels on the main floor were within acceptable levels on the day of inspection. The nailing schedule was checked with "rare earth" magnets and found to be perfect. The basement was also inspected and found to be finished and completely furnished, except in the furnace room area, which was located directly beneath the buckled area upstairs. There was a sump pump present next to the furnace. Moisture readings taken from the basement framework were approximately 2 percent greater than those taken on the main level.

The homeowner and I then sat down and began the interview stage of the inspection. My curiosity spiked when I learned that part of the basement was not finished when the homeowners moved in; in fact, they had closed in the furnace room when they first took possession of the home. I then continued my inspection and found that the final three rows in the buckled area had been glued to the subfloor with a premium construction adhesive.

This floor had nowhere to expand to across the widths of the boards. Red oak has a dimensional change coefficient factor of 0.00369, so it doesn't take much moisture change for this floor to move. After the furnace room below had been closed in, moisture concentrated in this area, and the weakest link allowing the floor to move was up.

How to Fix the Floor

The first corrective measure was to ventilate the furnace room to circulate the air and existing moisture so that it was consistent with the rest of the home. The dining room floor was repaired by removing the three glued rows and by removing and replacing the buckled area. I recommended new boards for the replacement, as reinstalling the same boards could cause further issues—the integrity of the board tongues may have been jeopardized by the original staples. The removed rows could then be replaced in accordance with the manufacturer's instructions and without the use of construction adhesive over the last rows.

In the Future

Don't underestimate the movement of hardwood. Any species of wood flooring requires expansion— especially across the board widths. This floor had the appropriate gap left for expansion; however the construction adhesive prevented the boards from taking advantage of it.

Drew Kern is a Toronto-based independent wood flooring inspector, consultant and claims advisor; and is an NWFA-Certified Professional Installer and Sales Counselor.



should professional laminate floor dealer with 30 year sell someone a laminate floor and provide installation for same to a homeowner without attending the home whereby he was unable to see the site conditions? How would the dealer/installer know whether screw the existing sub-floor down to eliminate any squeeks, or to determine if there is a need to provide leveling compound to the sub floor or if new plywood sub floor was required before the under pad and laminate flooring were installed? if this was the action oif a 30 year professional flooring dealer, what would you say? thanks art
art field    6/7/2013 3:30:33 PM

Job Title:
Email (not published):
(maximum 2,000 characters)  

Related Articles: Troubleshooting

Sweaty Situation: Steamy Job Causes Unusual Stain Problem (August/September 2014 - Charles Peterson)
I was called by a high-quality flooring contractor recently because in 24 years of doing wood floors, he had never seen marks ...

Mysterious Moisture: This Moisture Meter Reading Didn’t Make Sense (June/July 2014 - Brian Gerello)
I was contacted by a hardwood floor installer in South Carolina to determine why his moisture meter was displaying...

Incompetent Installers Lead to 'Crackling' Wood Floor (April/May 2014 - Aaron Roworth)
We were called out to do an inspection on a floor that we had sold but had been installed by a third party. The ...

Q&As: Wood Species ID, Squeaks and Applying Hardwax Oil (April/May 2014 - HF Editors)
I need to do a repair on a floor where I can’t figure out the species...

Cupping by the Key: An Unexpected Source of Moisture in a Gym Floor (February/March 2014 - Kjell Nymark)
I was called to repair a gym floor previously installed at an elementary school here in the...

How Many Wood Floor ‘Failures’ Start Before the Sale (February/March 2014 - Roy Reichow)
Awhile back I was hired to do sales education training for a big flooring retailer, so ahead of time...

Heel Accessories Prevent Dents in Wood Floors (December 2013/January 2014 - Karly McMillan)
Fun fact that many wood flooring professionals are all-too-familiar with: A 125 pound woman...

Coming Undone: Do Climate Extremes Really Cause Delamination? (December 2013/January 2014 - Dr. Dirk Lukowsky)
As engineered wood flooring becomes more prevalent, we are seeing increasing numbers of cases of delamination...

Coming Apart at the Seams: The Dry Season Is Hard on this Bamboo Floor (December 2013/January 2014 - Joe Tedder)
A complaint came in that the planks from a floating strandwoven bamboo floor were pulling apart at the seams...

Bubbles in a Strand Bamboo Floor Create a Sticky Mess (October/November 2013 - Jason Cantin)
About six months after installation, bubbles started to appear on top of a strand bamboo floor...