Advertisement

Search Articles:



Dark Spots Take Over an Engineered Wood Floor

By Jerry L. Kuehn
August/September 2009
print  Print          Download PDF

The Problem

Last January, I was commissioned by a flooring manufacturer to inspect a prefinished 3-inch engineered oak floor that had developed dark spots. The homeowner was convinced the flooring was defective and wanted the floor replaced.

The Procedure

The Gulf Coast-area home was late-1970s construction with a concrete slab. The homeowner had moved into the house in 2002; the home had been vacant for a year before the sale was completed. Prior to move-in, she hired a contractor to replace all the floor coverings with engineered wood flooring adhered directly to the slab.

The homeowner observed several small dark spots begin to appear in the floor 10 months prior to my inspection (about six years after move-in). These dark areas increased in size and now covered a large portion of each room in the home. She said she used the cleaning product recommended by the wood flooring manufacturer and never mopped the floor with water.

The Cause

By the time of inspection, the dark areas in the floor encompassed about 40 percent of the floor. Moisture content readings revealed the flooring was saturated with moisture. However, the flooring was not delaminating, and no cupping was evident. No visible water entry was observed, and the homeowner stated there had been no broken pipes. Interior relative humidity was above 75 percent and the temperature was 74 degrees Fahrenheit.

An investigation of the exterior of the home revealed the soil line was above the first brick row around the home's perimeter. A black plastic soaker hose was placed adjacent to the slab under the soil. Drainage of the flower beds was toward the concrete slab, with only a minimum amount of open areas for water to flow away from the slab. The homeowner said the previous owner suggested using the soaker hose to water the slab for an hour once a week to help prevent the slab from cracking in the summer.

Because the home had been vacant for a year before the new owner moved in, the slab may have been at an acceptable moisure level when the new flooring was installed (the installer for this job was long gone by the time of the inspection, so no information about moisture testing at the time of installation was available). After completion of the installation, the homeowner introduced moisture to the slab as suggested by the previous owner, but the new wood floor did not allow the moisture to evacuate through the surface as did the old carpeting.

How to Fix the Floor

The flooring had to be replaced at the homeowner's expense and the slab watering technique discontinued. Because the soil was above the level of the slab, the new flooring had to be treated as a below-grade installation. Unfortunately for the homeowner, she did not have recourse with the installer or the manufacturer of the wood floor under the terms of the warranty.

In the Future

Water and wood flooring do not mix. Even if a home is more than 30 years old, that doesn't mean the slab is dry. Seasonal changes affect the moisture content of a slab, and so does the grading around the house. Flooring installers should always perform a moisture test on a slab prior to installation, check the grading around the home's foundation and educate the homeowner about what moisture can do to a wood floor. Adding water to prevent slab cracking is often recommended but seldom needed in the Gulf Coast area. This was an expensive lesson learned by the homeowner.

 


Jerry L. Kuehn is a 40-year wood flooring veteran, an NWFACP CWFI, and technical services manager for T&L Distributing LP in Houston.



                    dark spots   

 Comments:

i too have dark spots which are spreading. installer claims moisture which didn't show at time of installation (less than 1 yr ago.) homeowners assoc. put in french drain & plumbers say no pipes are leaking under slab. don't know where to turn. now i find out that hardwood floors should not be glued to concrete slabs without some type of sub floor. is this true?
Jean  hardwood over concrete slab  10/12/2011 6:09:08 AM


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

Related Articles: Troubleshooting

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...

Early Finish Wear Results in an Unhappy Customer (August/September 2013 - Mark Mukosiej)
A contractor in the Southeast received a call two weeks after he put the final coat on a resand and refinish...

12345678910...>>
CONNECT WITH HF
FEATURED SUPPLIERS