How to deal with bulges and wrinkles in football fields?

During the construction of artificial turf for football fields, bulging and wrinkling are one of the most frequently reported problems by customers. These problems not only affect the appearance, but may also affect the service life and sports experience in the later period. UNIGRASS summarizes the common causes of these problems and proposes effective countermeasures to help construction parties and operators quickly solve the problems and ensure the quality of the venue.

Important Warning Signs

When artificial turf on a soccer field develops bumps or wrinkles, it's not just a simple aesthetic issue. It's a clear "ground warning" that may indicate:

• Athlete safety risks: Bumps can easily lead to sprains, trips, and other serious sports injuries.

• Impaired fairness: Unpredictable bounces in the ball's trajectory affect the quality of the game.

• Accelerated damage: The problem can quickly escalate, causing premature damage to parts or even the entire field, resulting in greater economic losses.

• Legal risks: The venue management may be held liable for failing to provide a safe field.

Types and Causes of Deformation

An accurate diagnosis must be made before any repair work is carried out:

• Local circular bulges: Local subsidence or frost heave of the base layer; accumulation of infill granules.

• Long strip bulges: Cracking or expansion at the turf seams; excessive tension applied to this area during turf installation.

• Wavy wrinkles: Low temperature of the base during installation, causing the turf to be in a contracted state; arching in summer due to no room for expansion after heating.

• Cracking/bulging at the seams: Failure of joint adhesive; poor quality or improper pasting of joint tape; insecure fixation of edges.

Common causes of bulging

Bulging is the phenomenon of local bulging and unevenness of the lawn, which affects the visual and foot feel. The common causes are mainly:

Improper transportation:

The grass roll is not fixed well during transportation, resulting in loose or deformed structure.

Unbalanced lifting:

Improper operation of the lifting equipment makes the center of gravity of the grass roll unstable, causing uneven structural stress.

Poor winding process:

The grass roll is not tightly rolled according to the standard during the production process, or the tightness is different.

Improper construction method:

The lawn is not laid or stretched as required, resulting in uneven stress release and bulging.

In addition, if the lawn is stored for a long time in a low temperature environment, bulging may also occur due to shrinkage and deformation.

Troubleshooting Methods

• Tactile and visual inspection: Step on the bulged area to feel whether it is hollow or solid underneath? Lift up the turf to check if the base layer is damp or loose.

• Drainage system: Check if the drainage outlets are clogged and if there are traces of water seepage around them.

• Edges and fixation: Check if the fixing nails and adhesive strips around the site have fallen off.

• Infill layer: Check if the rubber granules are compacted, unevenly distributed, or severely lost.

• Tool-assisted inspection: Use a level to measure slope changes, and a tape measure to measure the area and height of wrinkles.

Solutions to the bulging problem

The bulging problem can be solved in three ways according to different ambient temperatures:

1. When the ambient temperature is higher than 25°C

Open the grass roll and dry it naturally to soften the grass carpet;

Flatten the raised part repeatedly with uniform force along the direction of the grass roll unfolding;

If necessary, repeat the unfolding and flattening several times until the bulge disappears.

2. When the ambient temperature is lower than 0°C

Reroll the lawn in the original direction for about 50 meters and unfold it again to observe whether it is restored to flatness;

If there are still bulges, pour hot water at about 80°C evenly on the raised part;

Then cover it with a quilt or cloth for insulation, and step on it lightly with your feet or heavy objects to help the lawn return to flatness.

3. For small bulges at the head, tail or edge

Apply a proper amount of glue at the bottom of the bulge;

Press the lawn tightly with a roller or tool and squeeze out the glue;

Wait for the glue to solidify before performing seam treatment to ensure flatness.

Causes and effects of wrinkling

Wrinkling is similar to bulging, and is mainly manifested as wrinkles on the grass carpet surface. Common causes include:

Construction flipping or improper handling;

The glue at the joints of the lawn is not completely cured, causing movement;

The curling edge is nailed too tightly or the force is uneven, resulting in a "wood ear edge" effect;

Long-term stacking causes local deformation of the bottom layout.

Wrinkling will affect the leveling effect of the lawn, and then affect the service life and beauty of the lawn, so it needs to be dealt with in time.

Solution steps for wrinkling

Similar to bulging, wrinkling problems also need to be dealt with from the aspects of laying, unfolding, and placement:

1. Lay the lawn in an orderly manner

Align the lawns one by one and unfold them in sequence according to the direction of the design drawings;

Ensure that the direction of the grass fibers is consistent, and avoid tilting and reverse laying;

After unfolding, it should be placed on site for 24 hours to release the lawn stress naturally.

2. Evenly unfold and move

During the unfolding process, use even force to push the lawn smoothly;

Avoid pulling or loosening of the lawn during movement to reduce the risk of wrinkling;

Do not stop or fold it midway after unfolding.

3. Correct handling and stacking

It is strictly forbidden to throw, drag, or drop the grass roll;

Do not roll in the opposite direction to avoid damage caused by reverse stress;

The storage site should be flat and ventilated to avoid heavy pressure and tilted stacking.

Emergency Repair for Small Areas

If minor wrinkles or seam openings are suddenly found in a small area before a game, you can try the following steps:

1. Lift up the turf in the problematic area and thoroughly remove old adhesive, dust, and granules from both the base layer and the back of the turf.

2. Stretch the turf flat towards both sides as much as possible. If the edges are damaged, trim them straight vertically with a utility knife.

Alignment: Place the turf back to its exact original position, ensuring the turf fiber direction and splicing pattern are aligned.

Bonding:

Method 1 (Seam Tape): Place the seam tape under the seam, apply adhesive to the back of the turf and the seam tape, then press firmly.

Method 2 (Direct Adhesive Application): Apply adhesive evenly to the base layer and the back of the turf, let it stand until tack-free, then bond the turf.

3. Immediately place heavy objects (e.g., sandbags) evenly over the seam and press for at least 2–4 hours to ensure a firm bond.

4. Remove the heavy objects, evenly brush the surrounding infill granules back into place, and groom the turf fibers with a stiff turf brush.

If a large area of ​​lawn needs restoration, it is best to seek help from professionals.

Conclusion

The laying of artificial turf seems simple, but in fact every step requires careful handling. Although bulging and wrinkling are common, most problems can be effectively prevented and solved as long as they are operated according to professional construction standards. UNIGRASS is committed to providing high-quality turf materials and technical support to help you create a flat, beautiful and professional sports venue.