All-Season Structures

Innovative, Nonconventional Structures for Recreation, Sports & Fitness

By Rick Dandes

Advances in architectural design and engineering, and the evolving technology of moveable building materials, have made less conventional structures, meant to enclose year-round sports programs such as soccer, tennis and swimming events, a viable, cost-effective alternative to a bricks-and-mortar build-out, for private and public clubs, municipalities, and even larger universities and state projects.

"Conventional construction is generally thought of as bricks-and-mortar," explained Jim Avery, vice president of a West Jordan, Utah-based international builder of structures that utilize their own unique fabric membrane. "Everyone would like a brick-and-mortar arena as their sports facility," he said. "We'd all like it."

But the reality is, it's not always financially feasible. Whether the structure material is fabric, plastic or metal, the cost is generally less than funding a brick-and-mortar structure.

So, yes, there is a definite cost benefit to these structures, Avery continued, "but there is more to it than that. It's a faster speed to market. And the structures today are also high-performance. I wouldn't even call them nonconventional any longer."

One solution for those wanting to expand are fabric building structures, said Nathan Stobbe, general manager of an Easton, Pa.-based manufacturer. These buildings, also known as tension fabric structures (TFS), which can be used as either temporary or permanent facilities, have many of the qualities of regular buildings, but are available much faster and for a fraction of the cost.

The first type of fabric structures is a bubble, or an air dome, Stobbe explained. "They tend to be the least expensive way to span a wider width and to give you fields of play inside the facility. Air domes tend to be popular because they are the cheapest way to get into a large span facility, where you can play sports."

The challenge with an air dome, Stobbe said, "is they have high, ongoing operating costs, both from an electricity standpoint, to keep the dome inflated, and secondly, from a heating and cooling aspect because there is no insulation at that dome. Since the facility is pressurized, you lose a tremendous amount of heating and cooling just through escape through the fabric and through any penetration, holes."

The other challenge with the air facilities is, because they are pressurized, they create an environment where people inside might not feel 100 percent comfortable, "just because it has that pressurized feel to it," Stobbe said. "There is a human comfort aspect that is lacking a bit."

The third challenge with the air domes is they are held up by air, so if the power goes out or if there is a big storm or snowfall, they tend to go down, Stobbe said. Then, you have to re-inflate them. One of the reasons why people have indoor sporting facilities is to function during bad weather. And the problem with the air domes is when the weather is really bad, and you need them the most, you could have problems.

That's the reason why some people have chosen to move on from the air dome, and many operators who have built an air dome in the past, in the second round go to a more permanent type structure, Stobbe said.

Fantastic Fabrics

A fabric building is basically a metal frame, either steel or aluminum, with fabric cover, Stobbe said. Often, in athletic facilities, they are lined and insulated to create an ideal plain surface. Such structures are generally much more air-tight, and the fabric has thermally non-conductive properties, so it does not transfer hot and cold through the insulation as much as other building materials.

"This kind of structure is efficient because of lower air leakage and better thermal properties." Stobbe said. "The other benefit is it creates a very clean, smooth, interior finish to the building. It gives it a nice appearance … and the interior liner aids in providing soft and continuous lighting throughout the structure." For applications where the players need to look up, what you don't want is for players to be looking directly into a light and losing sight of the ball.


Fabric structures have been around for 40 years, so there has been a lot of innovation and modifications. "The first fabric structures were in Canada," explained Geoffrey Ching, sales manager for a structures manufacturer based in Windsor, Conn. "Obviously the weather there is very harsh all year long," he said. "If they hadn't been able to come up with something that was incredibly strong and adaptable to four seasons then the concept would have never taken off. There are different fabrics that are used. We suggest a polyethylene because pound-for-pound we think it is as effective, but less expensive than vinyls. With fabrics, there is always the option of flame-retardant additive to it, which allows it to be in compliance with any fire building code requirement. I wouldn't say there is anything revolutionary or new in the past few years in fabrics. I'm seeing the standards even better through advanced testing and understanding how they can make the fabric stronger. For instance, if there is a little hole in the fabric, it doesn't rip ... rip stop is the term. It is very easy to patch up if there is an issue there."

Ching illustrated the adaptability of fabric structures to various climates. "We have a structure down in South Florida where we have a pavilion covered. We have open sides, and open ends promoting natural ventilation, reducing the amount of energy used for HVAC systems. We want nature and natural breezes to take over as much as possible. If condensation becomes a concern, there are ways to design the structure to ensure that the user is getting exactly the environment they desire."

Avery suggested products that are aluminum-frame-supported so there is no air support requirement. "It is a building, per se."

This type of structure might have translucent daylight panels. "Since they are translucent, they add a lot more natural light inside," he said.

"If you put a little bit of glazing or glass on the side of it, you can really drive the 'wow' factor. Brighter, quieter, acoustics are great, and it is more energy-efficient because it is more airtight than a conventional building. We don't have any definition between roof and walls. It is consistent from top to bottom. They are completely re-configurable and relocatable."

Creature Comforts

Advances in architectural design and engineering, and the evolving technology of moveable building materials, have made less conventional structures, meant to be a viable, cost effective alternative to a bricks-and-mortar build-out.

The earliest fabric buildings were simple enclosures consisting of little more than a frame and a fabric cover. Today, with rigid frame construction and proven engineering, there are countless fabric building features you can include to suit your needs, such as rooftop solar panels, available for facilities that want to decrease their carbon footprint or go entirely off the grid, Nathan Stobbe said.

"Climate control is necessary in occupied buildings such as sports centers and entertainment venues that require a specific environment," Stobbe added. "Heating, cooling and air conditioning systems along with the tightly sealed building envelope of fabric buildings help maintain a consistent temperature. The non-conductive properties of fabric structures also enhance the efficiency of the fabric structure."

You might not know that you can add both active and passive ventilation options to a fabric structure, ranging from simple mesh eaves for intake to large powered fans, Stobbe said. Ventilation systems help the building breathe and supply a fresh source of cool air throughout the building.

Plastic Fantastic

Architects at Populous are using plastic cladding in their structures. Populous is an international architectural firm, based in Kansas City, with a reputation of building sports structures around the world, including at Sochi, Russia, for the 2014 Winter Olympics.

This particular cladding, ETFE, or ethylene tetrafluoroethylene, is one of the exciting new materials of the last few decades, said Ron Van Sluijs, associate principal at Populous. Van Sluijs, in one of his blogs, went into great detail explaining more about this versatile roof cladding system, which was initially used in greenhouses, but is now an increasingly common feature of stadiums and large atria.

Though ETFE is expensive per square meter, he said, the savings are considerable, because less steel structure is needed and installation time is much faster.

"It's a weather-resistant thermoplastic, which is UV stable with a high light and UV transmittance," Van Sluijs said. "The system is comprised of two or more thin foils sealed around its perimeter, internally inflated to form an enclosed cushion which is then inherently rigid, lightweight, capable of spanning large distances without immediate supports, and also is capable of bearing substantial loads, as well as being self-cleaning … to a degree."

The term "fantastic plastic" comes to mind when working with ETFE, Van Sluijs said. "The material is versatile and can look spectacular, particularly when used as a roof over a large venue. The material is interesting architecturally, structurally, thermally, ecologically, and is likely to be used more and more as a roof cladding option in the future. As a roof engineer and architect, I believe there is also a future for ETFE in public buildings where it can be applied in combination with newer trends such as green-wall-architecture, or as part of an internal atrium, enclosing a semi indoor-outdoor public space while positively adding to the climatic conditioning of the particular space."

Moveable Metal Structures

A retractable aluminum frame structure can also meet your facility needs. "With aluminum frame structures … one of the main benefits is the structure itself can handle, if it is an aquatic facility, all of the chemicals, moisture, condensation and humidity in the air without protection," said Cihan (Geon) Ozdemir, project engineer and owner of a Crown Point, Ind.-based manufacturer of retractable pool and patio enclosures. "From that aspect the structure itself doesn't need to be protected. To take it further, the fact that it is retractable can allow for outdoor use in an outdoor space within minutes and multiple times in a day can be open and closed so you can have that indoor-outdoor facility in one building or with one pool or just with one structure rather than having two separate facilities."

The structure's panels are made of polycarbonate, which does provide a greenhouse effect, Ozdemir said. From an energy-saving perspective this kind of a structure can be a huge benefit.

A retractable frame structure was just the solution decided upon by the town of Highlands, N.C., to enclose a pool. "We had discussed, in year's past, an air bubble," said recreation director Lester Norris. "But for a pool the size we had, a junior Olympic pool, we ultimately did not feel comfortable with that. We looked at an enclosed pool, where just the ceiling would open up. A retractable structure. The one we picked splits in the middle and it opens to where about 80 percent of the pool is wide open. Twenty feet on each end is covered. You also can close it and use it year around."

Consider the entire package of capital cost, reliability, performance long term and engineering safety, as you're looking at the occupancy of that facility."

As for financing, Norris admitted, "we wouldn't have had the money for this, except we had a donor in town who gave us the funds to buy the dome, have it constructed, and make some changes to our pool that would facilitate that.

"The donor stepped up and said, 'I'd like to see an indoor pool,'" Norris said. "We got together with our architect and started doing some investigation, and this was the only product we could find that would cover a pool this size and do what we wanted it to do.

The result is a retractable, aluminum dome. "It's on tracks, it splits in the middle. It is in six sections … it's a stable structure. We love it. Our patrons love it. We advertise it as an indoor pool in the summer. We would do this again in a heartbeat."

Bottom Line: Do Your Research

Before you get started, you need to know what you are trying to accomplish and what you expect at the end of the day. Know all this as you approach an architect or manufacturer. "Our first question to a potential client," Ozdemir said, "is always: What is it we are covering? And what are you trying to get out of it? We may not always be the best solution, but whenever we are called, we dive further into a client's needs, their wants. Literally, your savings can be in the millions of dollars by having your architects do their due diligence. Consider the entire package of capital cost, reliability, performance long term and engineering safety, as you're looking at the occupancy of that facility."

In some cases, money may not be a deciding factor. Geoffrey Ching recalls attending a meeting in Miami where the principals weren't as concerned about cost as they were about the architectural look. "How is this going to fit into the neighborhood landscape? For them, it isn't about the lowest cost per square foot, it's about wanting the residents in the area to look at the structure and say it's beautiful."

There are, however, some basic factors every municipality or organization (such as a YMCA, college or large university) has to consider in choosing a so-called non-conventional structure, Avery said. "And it begins with, does it meet your budget? It also must work, that's basic. In a lot of membrane-type structures one size doesn't fit all. In other words, an air-support structure may not be appropriate for a diving facility, but it might be appropriate for tennis."

Match the suitability of every product, Avery noted. "There are some lower-cost fabric structures in the market that don't provide proper insulation or membrane tensioning, and they are truly temporary.

"You cannot apply a temporary structure as a permanent building solution," Avery added. "You might, but you will be disappointed with the result not giving you the refined finish, the energy performance, the long-term performance, in that the membrane won't be tensioned.

"If you get wowed by low cost, you'd better go see the structure in person," Avery warned. "You need to go see whatever you are buying in fabric structures because there is a wide range of quality out there. If you go for too low-end a product, you'll never want to use another fabric building again, and you are setting yourself up for disappointment."



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