Feature Article - May/June 2003
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Tread Lightly

A complete guide to selecting the right sports surface

By Margaret Ahrweiler


INDOOR

Thoughts on wood

When it comes to choosing indoor sports surfaces, the main choice that looms is wood vs. synthetic.

PHOTO COURTESY OF BSA ARCHITECTS
Red Morton Community Center in Redwood City, Calif.

Wood remains the gold standard for multipurpose spaces for a variety of reasons, notes David Ross, a partner with BSA Architects in San Francisco.

"It has a sense of quality that's hard to compare with," he notes. "People know exactly what they're dealing with. "

Wood is prized for its appearance, its ability to return energy—the level of "bounce"—and its durability. If properly maintained, it can last up to 70 years or more, although many architects put its actual life span closer to 40 years. It's a known entity with a long history of performance. Plus, the very appearance of wood can demonstrate a commitment to athletics.

"Don't even think of designing an Indiana school with anything other than wood gymnasium floors," remarks Sandra Kate, architect with Fanning/Howey Associates, Celina, Ohio, referring to the fierce dedication to basketball that permeates the state.

PHOTO COURTESY OF BSA ARCHITECTS
Marin Jewish Community Center in San Rafael, Calif.

On the other side of the ledger, though, wood requires precise, committed maintenance. It expands and contracts with humidity and temperature changes, requiring a constant ventilation system; it becomes damaged if it gets wet; it requires skill in installation; and as a hard material, it has no point-elastic, cushioning characteristics.

Next, wood floors can be installed three basic ways, although manufacturers have developed dozens of slightly altered systems. Typically, wood floors are installed over concrete bases. On top is the layer of wood strips, usually maple. Underneath is the subsystem, which provides the resilience. This can include wood "sleeper" support pieces, panels of plywood, foam underlayers or channeled synthetic support systems. The floor also can be free-floating, meaning it is not mechanically attached to the subfloor but isolated from the concrete by resting on synthetic cushioning channels or other systems. It can also be anchored, where the floor's sublayer, which usually also features some form of cushioning, gets bolted to the concrete.

According to Johnston, sleeper systems tend to be the least expensive but the least responsive biomechanically because testing has shown that sleeper floors do not deform under loading, which can increase the potential for injury.

Multi-sleeper systems, which can feature a grid of sleepers, perform much better, he notes. Anchored systems cost the most but can withstand changing environmental factors the best.

 
LEFT: PHOTO COURTESY OF FANNING/HOWEY ASSOCIATES RIGHT: PHOTO COURTESY OF BSA ARCHITECTS
Left: Zionsville Middle School in Zionsville, Ind. Right: Roseville Sports Center in Roseville, Calif.

The next choice is what type of wood strips go on top. Maple comprises more than 70 percent of wood floors, but other hardwoods can work well too. For example, York Community High School's new competition gymnasium will feature a beech floor because in rebuilding the 70-plus-year-old school, the architects wanted to create an older, established look.

It's all About the Motion

The best flooring choices match up a sport's actions with a surface's responses. Here are a few of the motions planners take into account:

Basketball
ball bounce
running
jumping
foot turning/pivoting

Volleyball
jumping
horizontal slide
falling/diving
ball bounce

Aerobics/group fitness
jumping
horizontal slide

Dance
foot slide
turning/pivoting
jumping
spike (heel) resistance
sound transmission

Soccer
running
turning/pivoting
ball roll
falling
ball bounce

Inline hockey
gliding friction/adhesion

Tennis
ball bounce
foot slide
controlled foot slide

Track and field
running
jumping
friction/grip

Weightlifting
dropping
standing
load bearing
sound deadening

Yoga/Pilates
sitting
laying
balancing
standing

Indoor baseball/softball
training
running
batting
pitching
catching
sound deadening

Next, wood's installation issues need to be examined. A skilled installation team is essential with wood floors. Wood often must "acclimatize" or become accustomed to the indoor environment, and the team must ensure room for expansion and contraction. On the other hand, some systems should not acclimatize, and the installation team needs to know which is which.

"You need to investigate past installations and ask how they've performed for the owner," advises Gary Miller, assistant athletic director of operations at the University of Illinois Urbana/Champaign. "Then you have to ask who's going to install this floor and make it very clear in your contract. "

Miller has learned the hard way about how wood floors react to humidity and climate changes, having had an unanchored floor fail recently. As a result, he now specifies only anchored systems.

Finally, planners also need to select the coating, the finish applied to protect the surface. Johnston says his firm specifies only oil-modified polyurethane whenever possible, since these do not side bond or panelize, although water-based and moisture-cured polyurethanes also are available, with water-based the easiest to apply. A caveat, Johnston adds: Some jurisdictions do not allow oil-modified coatings due to environmental concerns.

Synthetic ideas

While wood often seems the most obvious choice for gymnasium and multipurpose floors, it may not always be the best solution, experts advise. Building owners should also consider the wide range of synthetics, which can be a better fit in many cases.

Synthetics, which cover anything but wood, generally fall into three categories: urethane, rubber and PVC (polyvinyl chlorate).

Synthetics also can be installed three different ways: either poured on as a liquid, rolled out in long sheets or put together like a puzzle as interlocking tiles.

These types of systems may represent the best choice in facilities for whom "multipurpose" means more than just a mix of basketball, volleyball and indoor soccer; it might mean a day filled with youth sports and adult recreational leagues, then spaghetti dinners and teen dances at night.

In these cases, clients may need to be talked out of a wood floor, says Indoor Courts of America's Scott Knackstedt, because the architect or consultant knows it's not appropriate and can't be cared for properly.

"Why would I give you a Porsche if I know you're never going to change the oil, let it get banged up and ultimately trash it?" he says. "It's the same thing with floors. "

PHOTO COURTESY OF MOOSE SPORTS SURFACES
Parkside Athletic Club in Pekin, Ill.

Architect David Ross agrees, noting that heavily used multipurpose spaces often don't see enough down time for the maintenance involved with wood floors. For those reasons, Ross specified a synthetic floor at the Roseville Community Center in Roseville, Calif., and the system garnered rave reviews from the owners.

"It would be in use nearly constantly, and at 11,000 square feet, it was to be one of the few spaces of that scale in Roseville," he adds. The vinyl flooring with fiberglass backing features a simulated maple pattern that looks "pretty convincing," Ross says, and promises a lifespan of about 20 years, with far fewer maintenance costs.

Synthetic sport surfaces' durability also can create interesting combinations for multipurpose facilities.

For example, the Parkside Athletic Club in Pekin, Ill., primarily serves as an indoor tennis center but also houses horses and cows (no kidding) during the town's fair.

PHOTO COURTESY OF RB RUBBER PRODUCTS
Salem Family YMCA in Salem, Ore.

"We recommended PVC sheet goods," Cottingham says, "and they've been unbelievably durable and easy to clean—they go in there with a power washer. "

A caveat, however: When selecting synthetic floors that will be used for court sports, Knackstedt cautions, building owners must look carefully at the floor's bounce.

"You can check the manufacturer's specifications, but the best way to find out is to visit another installation," he recommends. "You may discover their bounce range is all over the map."

Synthetics have tended to be too frictional with not enough "slip," Johnston says, adding that manufacturers have revised their products to reduce friction. At the other end of the spectrum, even more frictional synthetics can become slippery when dusty, Cottingham says.

Owners must also consider the chemicals and aromas involved with installing synthetics when making their choices, Cottingham adds, especially for facilities that remain open 24 hours a day or get constant, heavy use.

As area-elastic systems, the performance issues involved with synthetics differ from wood. Whereas wood floors create worries about dead spots and resilience, synthetics raise issues of loading, where the cushioning "bottoms out," making a heavy impact on users' joints. According to Johnston, synthetic surfaces that are 9 mm or less will bottom out. He recommends synthetic systems of a minimum of 15 mm for users' comfort, based on biomechanical research. Other industry pros have offered the opinion that the tendency to bottom out varies according to sport and intensity, so that 9 mm is sufficient.