Decades ago, when I first started installing synthetic turf, the turf was very different than it is now.

The turf itself was more like an outdoor short pile carpet look. You know, the green outdoor carpet that many put all over their porches. Most pile heights maxed out at ½” unless they were made for sports, and even the sports turf products were very short. Your compaction had to be very smooth, or all imperfections would reveal themselves through the turf. We either placed Coal Slag or Dirty Silica to keep it from blowing away, which we now call infill & ballast. Over the years, fiber configuration and pile heights have changed dramatically as well. Internal textured thatch was added, which assisted the stability of the product. However, one thing that has not changed: seam ruptures.

This month, Ask JW will express the importance of adhesive compression and why it is crucial for the longevity of the entire system.

Adhesive compression allows the adhesive to be forced into voids and capillaries within its adhesive zone and ensures the bonding performance. When the turf is laid upon the seaming tape, the stitch rows on the back of synthetic turf are elevated above the backings surface which leaves gaps running along the stitch rows itself. When the correct application of adhesive and total compression is applied, the compression will cause the adhesive to fill these stitch row gaps and voids. The compression will also push out any air that may cause future seam separation/rupture.

The images show close-up and cut views of how compression forced the adhesive up and through the stitch rows, gauges, and backing. Compression prevents voids and air pockets from occurring between the seaming tape and the backing of the turf, which gives longevity to the system. Optimum performance is when the synthetic turf adhesive is applied with the correct tool, at the correct thickness, with even compression throughout the curing process.

I recommend installing seaming tape and adhesive early in the morning or late in the afternoon to prevent yarn shrinkage. The heat of the day will not only cause the seam to expand and contract, but it will also cause the adhesive to cure too quickly. When adhesives cure before compression can be achieved, possible separation/rupture will occur.

I have seen so many ways that contractors try to achieve adhesive compression. Many of them I do not agree with, and there is a reason behind it. I had mentioned above “total compression”. Depending on the width of your seaming tape and adhesive application, you will need to figure out what you will need to use for the compression method. It is important to ensure that the entire seam line is compressed equally and evenly. I have seen contractors use everything under the sun for compression, and they will likely experience some type of seam separation if the adhesive is not cured and equally bonded throughout the seamline.

Depending on the adhesive and manufacturer’s instructions, compression may vary. When using the Superseam Adhesives (Pro 444 and 283C) and 12” seaming tape, I recommend using a 50-pound infill bag for seam compression. This will give the compression approximately 25 pounds of force per foot at 1/8” application thickness.

Input Interpretation

300 in lbf (pound-force inches) to feet = 25 ft lbf (foot pounds-force)

Believe it or not, placing bags on lumber will not give you equal and even compression.

The image to the left shows how thermal expansion will “call you out” on uneven compression. The entire seam line must be evenly compressed to prevent crowning of the turf. This contractor had to make costly repairs.

Emptying out turf infill and piling it on the seam is not a good method of compression. The piled infill may cause the infill to contaminate the adhesive during the curing process.

Using wooden pallets to bridge both sections of the seam line does not give enough force to compress the adhesive properly. It is also backbreaking to move from seam to seam and uncontrollable while maintaining the seam inspection during curing.

Water-rolling, depending on the length of the seam, may cause uneven curing of the adhesive. When urethane adhesives cure, they expand. The water roller may not stay ahead of the curing process and will leave behind elevated areas. Water-rolling of the seam may produce ripples in the seamline. A water roller may cause the turf to “wave” in front of the roller and cause the turf to lift. Be very careful and go slowly if you choose to water-roll.

When it comes to adhesive compression, timing is everything. I have witnessed contractors take off the compression too early and experience seam separation. I also have seen installations that were ruined due to the contractor leaving weight on the seam line overnight. DON’T DO IT!

The image to the left is showing many things that possibly went wrong during the application and compression process.

1. Adhesive thickness may have been too thin. It is crucial to read the adhesive manufacturer’s thickness chart, application rates, and curing times.
2. The adhesive was allowed to “skin” before compression was applied. Skin time is the time required before the surface of the adhesive is dry to the touch. If you have very long seams, it is important to have enough labor to assist in getting the adhesive applied and the seam line compressed before the adhesive starts to “skin”.
3. The seam did not have enough compression for the adhesive to compress, seep, and bond to the turf backing. You can see this by how clean the backing and stitch rows are.

The image to the left shows great compression, but one must be careful not to leave compression on too long.

It is imperative that you have enough team members to achieve successful seam installations. If you are short in manpower, you will be short in quality.

Most landscape synthetic turf needs ballast and Infill. I recommend using the infill bags (50lbs) to compress your seamline.

Having enough help will allow the “bag man” to camouflage the seam with the JW bagging trick mentioned below.

For more information regarding placing synthetic turf for putting green, or to schedule a training, please contact J.W. at  (888) 846-3598 or email AskJW@SGWcorp.com

Suggestions for the use of ASK JW installation techniques are solely at the end users’ discretion; however, the user should determine suitability for the intended use by his/her own evaluation. Because the use of the materials is beyond our control, neither ASK JW nor SGW shall be liable for the outcome of any use of said materials including any injury, loss, or damage, direct or consequential, arising out of the use or inability to use these techniques and products.