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Turf Flatness and Sub-Base Problems


June 10, 2019 0 comments Technical
Synthetic Turf Flatness Field Check – Photo shows an 18 mm (3/4 in) depression in a 1 year old field.

In many ways the most important part of a synthetic turf field is the sub-base. They control drainage and help maintain a flat playing surface. Owners and architects often take for granted that their installation will have a properly installed sub-base system. However, poorly installed sub-bases are more common than many realize and they lead to problems when the field is new and as it ages. This article focuses on how the sub-base effects the flatness of the field.

The following observations were from a recent filed inspection. This field had a depression that was nominally 3/4″ deep by only 2 ft wide. It ran across the field for 20-30 yards, and is likely associated with an improperly compacted or installed drainage system. This settling occurred in less than 18 months. It is unknown how much more or how quickly this area will continue to settle.

So, what happens if and when your field has similar conditions? First, owners should know that there are typically no requirements for the flatness of a finished field in North America. A flatness of 1/4 inch in 10 feet is commonly included in North American specifications, but that is typically applied to the sub-base level. Typically there is nothing in the spec that defines the required flatness of the finished turf field, or a specification for the field to remain within that flatness tolerance throughout the life is even more rare. FIFA certified fields are the only fields that contain such a specification with regard to the finished field, but such fields are expensive and generally unnecessary within North America.

There is no rule or standard that states a certain degree of un-evenness of a synthetic turf field is excessive, or unsafe. Sometimes, a turf installer will fix/fill the area on newer fields, and owners can request older fields to be fixed. In either case, owners should realize that in order to fix the field the turf will need to be removed and re-installed. Considering the benefits of the repair versus the potential damage from removing and re-installing the turf must be done on an individual basis.

Contact ASET Services if you have questions about the performance or appearance of your synthetic turf field, or any other sport surface. We’ll discuss your project and develop a unique test or inspection program with your needs and budget in mind.

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