Do your homework before building a synthetic sports field
December 6, 2013 By Mike Jiggens
Municipalities considering the construction of a synthetic turf sports field to help alleviate the amount of wear and tear experienced by their natural fields, or to have the means to increase their bookings, need to do their homework before taking such a major step.
Gord Dol, president of Dol Turf Restoration Ltd. of Bond Head, Ont., addressed an “introduction to synthetic turf” forum in November at the Guelph Turfgrass Institute, giving an overview of the construction, installation and maintenance involved with synthetic turf sports fields.
Presented by the Sports Turf Association and the Ontario Recreation Facilities Association, the forum attracted about 40 municipal sports turf managers and lead hands.
Dol, whose company has added synthetic turf field site preparation and installation to its array of services in recent years, said it is important to be familiar with all of the different products currently on the market before delving into something which may not be the right fit. Municipalities should also be adept with infill, basic construction methods and drainage.
“Always remember, the end product is only as good as the construction and installation,” he said.
Municipalities thinking about adding a synthetic field to their stable of natural fields would be well advised to visit sites in other communities which have already installed synthetic fields, he suggested.
When exploring a potential site for a field, it first needs to be tested by boring six to eight holes into the ground.
“You never know what might be hidden underground.”
From his experience, Dol said he has encountered such things as rebar, construction debris and buried topsoil beneath the surface of a proposed construction site.
Services such as storm sewers, water and gas must also be readily available at a proposed construction site.
If an existing natural field is being converted into a synthetic turf playing surface, it is vital to know its topsoil depth because it will need to be removed. Municipalities will need to be aware of existing irrigation and drainage as well as subsoil characteristics.
A detailed design of the project along with a good grading plan must be in hand before construction begins. Dol said it is important that an experienced design team be hired.
A typical drainage layout includes perimeter draining with various types of drainage in the field. It will be topped by about eight inches of clear stone and a couple of inches of various specific screens before the synthetic turf surface is installed. The field should be contained by either a concrete or rubber curb.
Disposal of existing topsoil and the addition of site structures are among other considerations to be made during the planning and construction stages.
“During the construction phase, it’s very important to have good quality control.”
Dol said this means hiring soils engineers to check compaction and the design firm to check grading to ensure everything is done properly and according to plan.
All design details must be followed, and specifications and materials must be tested to ensure they comply with the proper drainage properties.
When dealing with synthetic fields, grading has to be exact and is accomplished using GPS and laser systems.
“If you don’t have good grading, there are lots of things that can show up.”
One of the more challenging synthetic turf field projects Dol’s company undertook was the construction of a field at James Jerome Sports Complex in Sudbury, Ont. Built atop a swamp, the field’s site was not ideal, but the local council wanted it there and freed up the necessary funds to ensure the project would work.
Dol had done work at the complex in the past and found that frost heaving in the area could be as much as 14 inches. Synthetic turf will tolerate some heaving, but not 14 inches, he said.
It was found there was a foot of topsoil and another two feet of fine sand at the selected site, and it was the sand which posed the problem because it was at lake level. The three feet of material was taken off site and four inches of styrofoam insulation costing about $200,000 was put down. The styrofoam was designed to prevent from going too deep into the ground. Each inch of styrofoam prevents a foot of frost.
It took 11 tractor trailer loads of styrofoam to accommodate the entire site.
A drainage membrane was placed atop to channel all water to the outside. Six inches of aggregate was added along with a plastic product to provide dimensional stability.
Rock and tree stumps were among the material found at the site. Because of its location on a flood plain, the original grade could neither be increased nor decreased. Having to put down almost three feet of aggregate contributed significantly to the overall cost of the project.
Due to the site’s relation to lake level, a couple of large tanks were placed in the ground to allow for water collected from the field to be pumped into a neighbouring creek. One of the challenges associated with placing the tanks was to ensure they wouldn’t be displaced if the water table got too high.
Dol said that although the field’s location in the city was ideal, its particular site was not.
Once a synthetic turf playing surface is installed, it must be infilled with either a mix of all rubber or a sand and rubber mixture. It is usually installed with a typical topdresser and then brushed in by a machine similar to a miniature road grader equipped with a power brush. Seven or eight applications would normally be made to achieve the correct infill depth, with each layer brushed in before the next is added.
Often, static might be encountered on the field, Dol said, in which case a solution of water and Downey can be sprayed onto the surface ahead of power brushing.
Securing the field site is vital for vandalism prevention, he said, as there have been cases of motorists entering the grounds and willfully spinning their tires on the surface.
“Not allowing any vehicular access to the field is very important.”
Dol said sports turf managers need to know the groups booking their synthetic turf fields and to be aware of their intentions. He said an unfortunate situation once occurred at Etobicoke’s Centennial Park Stadium after a weightlifting group was granted permission to use the field for an event. Afterward, when the field was inspected, about 40 holes were found throughout the field, each four to six inches in depth. The holes were filled with sand in a half-hearted attempt to cover them up. It was learned the array of holes was created by the frequent dropping of heavy weight-laden barbells onto the turf without the use of any type of protective buffer.
“This caused the field to be closed for almost three weeks.”
By the time the city got its quotes and went through the various procedures to get the repair work started, a football doubleheader was fast approaching, leaving little time for the patch work.
For each of the holes, the turf needed to be opened and the grade prepared. In several instances, the turf had been stretched from the damage which required form cutting. The cost of the repairs was about $ 20,000.
“That’s all because a bunch of bozos were dropping weights on the field.”
Even though synthetic turf sports fields can be classified as low maintenance, it does not mean they are no-maintenance. Litter, for example, will not go away on its own, and the turf manufacturer’s maintenance instructions should be followed to keep the field of foreign contaminants. A manual provided by the manufacturer will detail what types of maintenance should be done and which ones should never be attempted.
The Synthetic Turf Council has a good manual available, but Dol recommended the guide provided by the manfacturer be the preferred choice.
“You will have to broom the field from time to time.”
When the infill has become too compacted, a set of steel tines affixed to a machine similar to a golf greens groomer can be used to break up the rubber. Dol cautioned, however, that the tines should be removed when they’re not needed to avoid premature wear on the field.
“As far as I’m concerned, this is a necessary tool to have,” he said, recommending it be used only after a G-max test has been performed to assess how hard the field surface has become. If an individual qualified as a G-max tester finds the field to be slightly too hard, “that’s the only time you should bring those out.”
Grooming should always be done in different directions to minimize wear, and driving over the same spot over and over again should be avoided. Traditional high-wear areas of the field will likely require special attention.
Specially-designed sweeping units will pick up loose debris such as peanut of sunflower seed shells from the field while a magnetic attachment will collect small metallic objects such as pins or nails.
Dol warned not to overdo brushing, steel tining or sweeping because it will cause premature wear to the field.
One concern among those contemplating the construction of a synthetic field is the possibility of staph infections among its users. Bacteria that can lead to infections can get caught in the fibres, but Dol said he has found it is an issue much more common in the southern United States where it is warmer than it is in Canada. Most staph outbreaks, he said, usually occur in the locker rooms rather than on the field itself.
Indoor fields void of rainfall and sunlight that would help break down harmful bacteria are more susceptible than outdoor fields. The threat of staph can be addressed by going over a field about three times at a controlled speed with a device which emits ultra-violet light.
Synthetic fields designed around soccer and football can be utilized for other sports such as field hockey and lacrosse, but will require specially painted lines specific to those sports.
“Make sure you use the right paint,” Dol said. “If you don’t use the right paint, it may not come off. You also need to be aware that if you keep doing it over and over and over, chances are you’re going to get some ghosting.”
When a field is used for a high-traffic event such as a concert, temporary flooring can be placed atop the turf to protect it from damage.
Removing snow or ice from the surface must be done with extreme caution.
“If you’re going to clean snow off, be very, very careful that you don’t damage it.”
Dol said snow removal equipment should not dig in or gouge the surface, and blades should be fitted with rubber tips. Wheels should not be allowed to stick to the fibres, and de-icing agents should never be used.
Fields can get extraordinarily hot during the summer with surface temperatures greatly exceeding air temperatures. In Ontario, perhaps a half-dozen days each year will be deemed unbearable, and some municipalities may have watering systems installed to cool down the playing surfaces. Dol said it’s an expensive option, especially when only a handful of days might require the additional water.
He said there will occassionally be instances when some minor repair work may be required.
“Sometimes you’ll have to perform a little surgery on your fields if someone does some damage, so it’s important that you keep some material from the original installation.”
It’s also wise to keep on hand manufacturer-supplied adhesives and cutting tools.
In the event of stains, soap and water can usually take care of most, but municipalities have the opportunity to be pre-emptive to minimize the frequency and degree of stains. Some municipalities have enacted a zero-tolerance rule which prohibits food or drink to be taken onto a field, unless it’s water. Athletes will have to leave the field at an opportune time if they wish to eat.
For tougher stains, harsher cleaners may have to be used, but Dol recommended no one guess at the type of stain because some cleaners and solvents can melt the turf.
“Know what you’re dealing with and use the right products.”
Chewing gum can be removed by freezing it with an aerosol refrigerant and then chipping it off. Bodily fluids such as blood should be blotted first and then cleaned with soap and water and perhaps a disinfectant.
High-pressure cleaners should be avoided altogether because they will damage the turf and displace the infill. Solvents containing bleach should never be used because they are harmful to the fibres.
Municipalities should place an ample number of garbage receptacles around the field to encourage proper disposal of waste and minimize the amount of debris getting onto a field.
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