Cork Tile Flooring Inspection
The Hartford Public Library
500 Main Street Hartford, Connecticut

 

Commissioned by: Fletcher Harkness Cohen Moneyhun, Inc.
46 Waltham Street Boston, Massachusetts 02118

Concerns

 

This inspection report is prepared in accordance with an inspection proposal and contract submitted by Kenneth J. Frango on April 16, 2002. The proposal was approved and accepted by ________________________, Inc., henceforth to be referred to as FHCM. Kenneth J. Frango was commissioned on May 5, 2002 by FHCM to perform the inspection.

 

he primary concerns of FHCM are due to the possibility of overall system failure of the natural cork tile flooring installed in a new addition of the Hartford Public Library. This new subdivision located on the third floor of the new building will be dedicated as the Children’s Library. According to FHCM their concerns stem from a history of previous adhesive bond failures in the same area.  The integrity of the contractor performed replacement of the respective areas that had already experienced failure are in question.

 

FHCM is not pleased with the aesthetics of the entire area including the replacement work and are concerned as to whether the conditions exhibited in the finished floor will contribute to premature and excessive wear and or diminish the integrity of the bond. Their paramount concerns are of the likelihood that these characteristics may cause harm, injury, or loss.

 

 

  Inspection

A preliminary walk through inspection was performed on the evening of May 16, 2002 at 7 PM. A full inspection commenced on the morning of May 17, 2002 at 9 AM.

Figure 1

The area inspected constitutes approximately 9183 square feet of Wicanders brand agglomerated cork tile flooring installed in four separate sections over a concrete substrate. Dimensions of the tile are 12” X 12” with a total thickness of 3/16 inch. Forty tiles were measured for squareness and all complied with standards set forth in ISO 3813 (<0,10º/ <0,5mm) of the International Organization for Standardization.

 

Two sections (A & B as indicated in figure 1, above) are connected and accessed through thirty-six inch wide doors. The entry has a wide rolling door that separates the Children’s Library from other sections of the third floor.

 

Conditions at the time of the inspection were of a comfortable and appropriate temperature of 78° and 35% relative humidity. The north wall (top of graphic above) has windows that extend from the top of a low bench or shelf to the ceiling line. The south wall (bottom of the graphic) consists of floor to ceiling windows.

 

Inspection-flatness

The evening sun produced incident lighting that revealed undulations or a wavy appearance to the finished floor as figures 2, 3 and 4 indicate.

 

Figure 2

 

Figure 3

 

 

Figure 4

The photographs above depict a concrete slab that far exceeds the cork flooring manufacturer’s and the flooring industry’s maximum allowable tolerances for flatness of 1/8 inch in ten feet. Using a laser square (model SL-24) I measured the floor for flatness in various areas and the test results indicate no better than ¼ inch in five feet. This is four times the maximum allowable limit and a floor with the tendency to reflect light such as this one should have never been installed without using corrective preparation measures to the substrate. 

 

Not only is this floor unappealing to the eye, high and low spots may expose the responsible party to additional liability in terms of injury, and uneven wear. Furnishings that may not sit level or need radical adjustment to obtain level may also add to this liability.

 

This was the initial and most obvious sign that correct installation procedures have been ignored. This also leads one too wonder how a contractor can permit an interior concrete substrate to be poured that appears about as flat as exposed concrete found in a parking garage.

Inspection-obvious bond failure

 

The next few photographs depict obvious bond failure. This is a clear sign that the tile is not adhered to the floor in these areas.

 

Figure 5

 

The Children’s Library is a new addition to the building and presently it is unoccupied. The floor has never been subjected to normal foot traffic outside of the building trades. No toppings beside the factory finish have been applied to the flooring and no maintenance has been administered.

 

As per manufacturer’s recommendations this type of installation requires a low VOC, (volatile organic compound) latex based pressure sensitive contact cement applied to both the concrete and the back of the tile. Inspection indicates that the proper adhesive was used. Though in this part of the main section there was no indication that adhesive was applied to the back of the tile.

Inspection-obvious bond failure

 

Figure 6

 
The area in figure 6 outlined by the circle indicates poor adhesion. Notice also that what is often referred to as a saddle or narrower width of tile was installed at the threshold of the door. The site cut tiles were compacted against the factory cut tiles forcing the tiles up. This type of pressure sensitive contact adhesive normally holds the tile firmly to the substrate. Applying pressure to the surface of this bubble forces the tile to lie flat temporarily but the bubble returns within a short period.

 

The lack of adhesion in this critical high traffic area indicates an obvious disregard for standard and proper installation procedures. 

Inspection-obvious bond failure

 

Figure 7

This photo of a tile in the main area shows a tile lifting at its edge. Something under the tile is forcing it up and has telegraphed through to the surface creating a pimple. There are many areas such as this throughout the installation. This is yet another example of the disregard for quality installation.

 

Figure 8

Inspection-obvious bond failure

 

Figure eight shows the debris (a small piece of cork) causing the pimple in the tile. The tile was obviously not bonded and lifted with minimal effort. It’s important to note here that this was the first indication of adhesive legs. Legs tell the installer that the adhesive is working as it was designed. The small piece of cork is well bonded to the concrete substrate. The adhesive is on top of the cork debris and on the bottom of the tile. Lifting the tile produces the stretching of the latex based adhesive forming adhesive legs.

 

This test proved a number of things. The adhesive is not defective and that the cork can be well bonded to this concrete using the recommended adhesive. There was some left over adhesive on the job site that I tested and it performed flawlessly.

 

These legs also tell another story. Knowing how this installation should be performed this small piece of cork debris should not be holding this tile up off of the floor. It will form a pimple but considering the strength characteristics of this adhesive the tile should be well bonded all around the cork debris. There should be no adhesive on top of the debris because this is a dry installation. In other words the adhesive is applied to the concrete and it is applied to the cork. When the adhesive has dried to the touch on both sides the tile is set and pressure is applied forming a permanent bond.

 

In order for cork debris to get under the tile it must have come from the cork tile as it was being placed or when adhesive was being applied to the tile before such placement. Not when adhesive was being applied to the floor. I’m surmising that the tile was placed in with wet adhesive on it’s back and possibly wet adhesive on the floor. This would explain adhesive on top of the debris. It would also explain why the tile around the debris was not bonded. Wet adhesive will not bond because of its inherent moisture. Though if the debris held up the tile enough to let the moisture escape or flash off it would bond to what it was in contact with. Which in this case was the small piece of cork debris as the inspection photo indicates.

 

Laying the tile into wet adhesive will cause other installation related problems such as gapping, shifting and double shifting creating windows. These problems are apparent throughout the installation. 

 

Figure 9

 

Laying the tile into wet adhesive will cause the tile to inadvertently slide as the installer works on top of them. He must work on top of the cork because he would contaminate the adhesive that had been applied to the concrete if he worked on it. This is a common problem as production installers who mainly install VCT (vinyl composition tile) are not accustomed to applying adhesive to the back of tile. They also have no patience and are not able to coordinate a job so they can be productive as the adhesive flashes off.

Inspection- shifting & gapping
 

Figure 10

 

Gaps and wedges similar to what this photograph shows can be found in numerous places throughout the installation. Soil will collect in these gaps and normal maintenance and use will dislodge these wedges. This will inevitably cause bond failure.

 

It’s important to note that witnesses to the installation describe the installers as starting on the far east side of the main section and working towards the west side. This installation should have been started in the center of the main section and preceded diagonally to finish in the corners of the four quadrants working the tile through the doorways of sections A and B. Separating the areas into equal quadrants and working across diagonally will significantly reduce tile run off in a straight lay installation. The industry standard loose lay and compaction installation method should be followed to accommodate tile and sub floor variations. See tile setting diagram (figure 11) on the next page.

 

Figure 11

 

Figure 12

Shifting of tile that occurs both vertically and horizontally causes a gap known as a window. In figure 12 the installer closed the window with a small piece of cork tile that will work it’s way out over time.

Figure 13

Figure 13 depicts ledging or lippage. This is when the edge of the tile is raised to a higher level than the adjoining tiles. This is a bond failure and is apparent throughout the installation. Normal use of this floor will cause these tiles to be kicked up and broken.

 

Figure 14

Inspection- Adhesive bond

 

Figure 15

 

Figure 15 shows many of the issues already reported. In addition there is glue on the face of the tile in numerous areas throughout the installation. At this point dried adhesive is difficult to remove and this is just another statement of a low quality, sloppy installation.

 

Notice how some of the tiles have proud edges. This problem is due to a combination of adhesive bond failure and over compaction of the tiles. This is one of the areas that have been replaced and chances are that the installer attempted to force tiles into a space that was too small.

Figure 16

 

In a separate replacement area Figure 16 also shows proud edges and an insufficient bond. These edges will receive excessive wear that result in tile cracking and soil penetration. Eventually these tiles will dislodge leaving voids and a tripping hazard.

 

The tile inside the white circle is one of many that have a color differential. Cork is a natural product and no two pieces are identical. Though this replacement lot had color variation that was obviously different. Adding to the obvious conclusion that this is nothing more than a poor patch job.

Figure 17

 

Forty pull tests were performed throughout the installation, 90% failed. There was at least one test performed in each section on the floor plan. The location of these tests are defined by black dots and indicated on the floor plan located in figure 1, on page three. Pull tests simply indicate how much force is required to remove the tile from the floor. In figure 17 a four-inch diameter circle was cut from the middle of a tile selected at random.

 

A good bond would be defined as a tile that would need to be scraped out in small pieces. An overwhelming majority of tests proved that little to no bond existed between the tile and the substrate. This particular test above is one that failed but did exhibit a very small amount of adhesive bond. Most tests exhibited a bond no better than that found with masking tape. Figures 18 and 19 show the typical bond that is present in this section of the library.

 

Figure 18

Corners of these tiles were effortlessly removed with little adhesive left on the concrete and no adhesive legs at all. No evidence of excessive moisture vapor emission was discovered and the slab measured an adhesive friendly pH of 6.

 

Figure 19

Five percent of the pull tests performed exposed a foreign substance on the slab that resembles paint used by contractors for marking. The following photo shows one of these pull tests. This is yet another indication of poor installation practices.

 

Figure 20

 

Paint acts as a bond breaker between the finished flooring and the substrate. Also the discovery of a foreign substance on the slab in 5% of the pull tests may indicate a disregard in adequately preparing the concrete to accept finished flooring.

Figure 21

 

Figure 21 demonstrates a pull test that clearly indicates no bond. Zero adhesive residues on the concrete with a thick layer of adhesive on the back of the tile. As previously described on page ten, per manufacturer’s instructions adhesive is applied to both the floor and the tile. The adhesive is dried and the tiles are then permanently placed. Bond is achieved on contact so care must be used to place tile in the correct position, as adjustment is not possible. I believe the tiles were set into wet adhesive. Moisture from the curing water based adhesive escaped into and around the sides of the porous tiles, as moisture will find the path of least resistance.

 

Premature setting of the tile retarded the adhesive flash (moisture evaporation) and caused it to cure abnormally. The adhesive exhibits cohesion and adhesion to the tile but no adhesion to the concrete slab. My explanation for this is that the wet adhesive not only acted as a bond breaker but also reactivated the adhesive on the concrete causing it to produce only cohesive characteristics.

 

Figure 22

Figure 22 shows a pull test in that the adhesive can and will bond to the concrete. Notice the bonding agent on the concrete and also observe the texture of the adhesive on the back of the tile. No adhesive bond was discovered in this test but the texture is indicative of what will form if the tile was wet set.

 

Figure 23

 

In figure twenty-three I used the sharp edge of a utility knife blade to scrape away the topical concrete sealer. This test revealed a dry flaking concrete slab that chipped away with little effort. This could indicate over watering of the slab as it was poured. Between this and the horrible leveling job I would be concerned with the integrity of this floor. I suggest that a reputable concrete testing company be used to take core samples and test the slab for overall integrity.

Conclusion

 

The adhesion of the same cork product in other sections of the library proved to be at the very least, adequate. This leads me to conclude that the flooring, adhesive and sealer system have been properly matched.  No evidence of excessive vapor emission or intolerable pH exists.  For inevitable flooring system failure to occur in the Children’s section, one or more of the components would have to be improperly applied. Currently without lab analysis of the collected samples it would be difficult to pin point the element(s) of the system that was applied or mixed improperly. Though not enough time given to the adhesive to flash is a common bond breaker and one major cause of shifting tile that is evident throughout the installation.

This floor has experienced system failure since it’s installation. It continues to fail and will continue to fail as long as it remains. Not only is it aesthetically unattractive all of the characteristics outlined in this report that describe it as so will eventually lead to further continuous failures. My recommendation is that a competent and reputable flooring contractor replaces the flooring.

 

Performing bond testing at each level of the installation will insure a long lasting satisfactory installation, as it originally should have been. Prepare the concrete substrate using one of the following methods: shot blasting, mechanical sanding or scarifying to remove the adhesive residue and sealer. I believe the integrity of the concrete to be suspect and I recommend core samples be taken and tested. Install self-leveling cement with primer to bring the floor as close to the flooring manufacturer’s tolerances as possible without adversely affecting adjoining sections of the library. Install new cork flooring from the center of the large area working across diagonally to the corners of the quadrants, as outlined in figure 11.

I had an in person private consultation concerning this project with renowned and respected flooring expert ___ ______ on 5-22-02. Mr. ______ has over forty years experience in the flooring industry and has achieved worldwide recognition as a professional installation consultant and inspector. We are in complete agreement as to the nature of the problem and the recourse required to rectify it.

 

In truth,

Kenneth J. Frango

To see a step by step narrative pictorial of a residential Cork Tile Installation performed in Paradise Valley, Arizona click here.

Credentials

 

·       Twenty-two years experience in the flooring installation business.

·       Member of the United Brotherhood of Carpenters and Joiners of America from 1982-1987. Experience installing various commercial floor coverings throughout the New York City metropolitan area.

·       Independent floor covering contractor based in New York from 1987-1994 installing high end and exotic floor coverings through out the NY metropolitan area and Long Island’s Gold Coast.

·       Relocation to the Phoenix, Arizona metropolitan area in 1994.

·       Arizona State licensed, bonded and insured floor-covering contractor since 1995. License# C-08 108-590 with zero complaints reported.

·       Certified member of the International Certified Floorcovering Installer Association in 1998 CFI #6126

·       Certified at the flooring industry’s highest installer certification level, Master-II in 2001. Only 25 installers out of 14,000 are certified at this prestigious level.

·       Recipient of the prestigious Charles R. Gress memorial award in 2001. In recognition for unselfish contributions in promoting quality floor covering installations.

·       Charter member and founder of the local Arizona State Chapter of the Certified Floorcovering Installer’s Association.

·       Present Treasurer and immediate past President of the The Grand Canyon State CFI Chapter.

·       Winner of the World Floor Covering Association’s 2000 Northwest Regional flooring installation contest for best installer in the northwest United States.

·       Winner of the World Floor Covering Association’s 2001 Southwest Regional flooring installation contest for best installer in the Southwest United States.

·       Winner of the World Floor Covering Association’s 2002 National flooring installation contest for best installer in the entire United States.

·       Presently the Certified Floorcovering Installer Association’s Chapters and Media committees co-chairman.

·       Member of the Installation Assurance Program assessment team. The flooring manufacture’s products are submitted, tested and accessed for install-ability.

·       I presently have a seat on the Certified Floorcovering Installer Association Board of Directors until 2004.

·       I’m a Pergo laminate endorsed commercial contractor 1999.

·       WilsonArt laminate factory approved installer 2001.

·       CFI certified inspector for floor covering installation 2002.

·       Installation trainer for the Certified Floorcovering Installers Association, Karastan Carpet Mills, Roberts Consolidated Industries, and the World Floor Covering Association’s Regional Installation Training and Education program.

·       2001 Trained and practicing the art of carpet dye application, correction and color blending.

·       Invited guest seminar speaker relative to solving the floor covering installation crisis at Surfaces. The largest annual floor covering industry trades show in the nation.

·       World Floor Covering and Arizona State Floor covering Association member.

·       Attendee of numerous and varied training and educational seminars.

·       Proficient in the installation of all types of floor covering.