Sealing the carpet edge with thermoplastic.


Finished staircase installed without unsightly staples.

In the spring of 1993, I met Michael Hetts, CFI Master #30, who at that time owned Smiling Tiger Enterprises in Chicago, Illinois. He attended the AMOCO-sponsored FCICA seminar that I was conducting. He was very interested about becoming more involved on a national level with installation.  Shortly after that meeting, CFI was founded in Kansas City, Missouri with the first certification scheduled for the following September. He called after reading about this and was insistent that he attends. It was somewhat difficult to convince Michael that the first certification was only open to the members of the four CFI Chapters. After a lengthy discussion, he appeared in Kansas City for the first open certification in October of 1993.

At the time, he had taken a position with Roberts and it was quite a competition between him and Ralph Richins, also of Roberts to receive the highest scores for the written and skills test. There was a point where members of the Team were not real sure about Michael. During the seaming of the berber, he constructed his seams with a glue gun!



Seaming the carpet.

This was interesting to me and as most installers have heard me say many times, “If you have something that will improve or add to our skills, I’m taking it to share with others I meet.” This technique presented real merit because at that time many installers faced difficulties with the seaming of berbers. He sold me! And, of course he and Ralph #28, both received their CFI Master with no difficulty. I don’t remember who scored the highest, but I’m certain if you ask them, they know!

Our company began using this technique and added it to the installation of stairs as a way to avoid the ugly staples that can ruin a beautiful creation if not meticulously used. Since that day, this technique has been shared with thousands of installers through CFI. The detailed stair installation demo prepared by Fred Chastain, Jerry Miller, Roy Davison and other CFI members is available at www.CFIinstallers.com. Thousands of installers were using this procedure for years before it became an industry-recognized technique.

Michael has shared his expertise with the readers of FCI magazine and installers worldwide of the use of thermoplastic to eliminate seam peaking. It is a common fact that direct-glue or double-glue seams do not peak. Peaking occurs when the carpet is stretched. If you follow the guidelines in the CRI-104 or 105 for every backing, you will encounter seam peaking. Carpets are like people; they all have their own characteristics and the installer must understand this for cutting, seaming and stretching. Seam peaking and seam elevation are inherent characteristics of hot-melt seaming when carpet is stretched.



Sealing the seamed edge with thermoplastic.

Use the glue-gun to weld the seams together during the sealing of the seam edges during the initial installation or refer to the following procedure:

I recommend that during the initial installation if it is known that the particular style of carpet is susceptible to peaking, that the procedure be incorporated to avoid a callback. Let me add one thing, the correction of seam peaking as well as the inclusion of this technique in the original installation are chargeable items and are not considered part of the base installation cost.

Seam peaking and seam elevation are inherent characteristics. This condition occurs when the carpet is stretched. The hinging motion causes the seam to become elevated because the thickness of the two separate backings is not welded together when using hot-melt tape. They are laying as separate sections on top of the tape. When the carpet is stretched across the tape, the seam becomes elevated, which created the peaking effect.

Seam tape profiling is created when a low-profile seaming tape is not selected. The width of the tape telegraphs through to the face pile. There are certain conditions that make this more prominent. When the artificial or natural light source falls across the seam rather than running parallel to the seam, seams should be constructed on a hard surface using a low-profile tape to achieve the correct transfer of thermoplastic.

The use of radio-wave technology is another step to eliminate seam peaking because the two sections of carpet are welded together when using a glue gun with the seaming tool.

When seam peaking occurs, it can be solved IF the cushion is acceptable. This procedure works only with cushions that have a scrim to support the applied adhesive. This procedure will not correct the appearance of the seam if it is not constructed in an acceptable manner, but it will correct seam peaking or seam elevation.  It is important to note that the cushion will have an effect on the success of this procedure. The recommended cushion is to be manufactured with a scrim and a minimum density factor of six-pounds. The room is to be empty.



  • 1. Remove carpet from tackstrip and pull it back to where the seam tape is visible. If the seam was originally constructed improperly on top of cushion, the tape left an impression on the surface of the cushion. Move to the right or left of this impression six inches and cut cushion. To identify seam location later if it was correctly constructed, place masking tape at each end of the seam on wall base BEFORE removing the carpet.

  • 2. Pull the cushion back and apply the pressure-sensitive adhesive using a 1/16”-by- 1/16”-by-1/16” square-notched trowel. Apply adhesive under the impression left on the cushion approximately one foot on both sides of where the cushion was cut. Allow the pressure sensitive adhesive to become tacky before positioning the cushion into the adhesive.

  • 3. Do NOT take the seam apart. Lightly sand the back of the seaming tape to remove the silicone, as it is not compatible with the adhesive.

  • 4. Apply an adhesive that is designed for double-glue applications to the top of the cushion the width of a trowel (1/8”-by-1/8”-by-1/16” U-notched trowel), approximately 10-12 inches, directly over the impression of the tape. If six-inch tape has been used, apply the adhesive 14-16 inches.

  • 5. Position the carpet in the adhesive while it is wet in order to have sufficient slip time when stretching the carpet.

  • 6. Immediately reinstall the carpet using the power stretcher. If necessary, stretch more on the length and less in the width. Stretch the carpet across the seam back to the original stretched position. DO NOT OVERSTRETCH!

  • 7. After the carpet has been edged into the gully, stretch the length of the seam using the required pressure to obtain a flat seam.

  • 8. Roll the seam with a flat seam roller (not to exceed 35 pounds) to ensure that the adhesive has been transferred into the backing of the carpet.

  • 9. A flat weight, such as a 2-by-10 or 2-by-12, should be positioned over the seam for approximately 45 minutes. This will allow time for the adhesive to become tacky and pull the seam down.

  • 10. Advise the customer that the area is not to receive foot traffic for 24 hours.
Remember, this procedure will not work if the cushion is manufactured without a scrim or the density factor is not sufficient. The adhesive will migrate into the cushion causing it to collapse. Before this procedure is attempted, always identify the cushion!