London’s Wembley Park includes a covered play area to attract families—with a coated fabric that resists dirt.
Wembley Park has a long history. An urban renewal success story, it’s been transformed again and again to fit the needs of the times. In 1880, the Metropolitan Railway opened a line across what was then an estate. Chairman Sir Edward Watkin had a vision to create a new kind of leisure destination for Londoners on the grounds that could be accessed by rail. In 1894, Wembley Park opened with a music hall, sports fields and a lake for boating.
The first Wembley Stadium opened in 1923, and Wembley Arena in 1934. It was the site of the Olympic Games in 1948 and 2012, and remains a destination for sports, music and cultural activities.
Now Wembley Park is undergoing another redevelopment to turn it into a new kind of urban destination. The owner and operator, Quintain, has a vision for the property as a mixed-use district that includes residences, shopping and leisure activities.
The development includes London Designer Outlet, which opened in 2013. The first outlet mall in the city of London, the shopping center features 264,000 square feet of retail, restaurant and leisure space, and includes designer shops, restaurants, movie theaters and an outdoor play and performance area.
A defining moment
The outdoor play space was an important component of the development intended to attract families—a place where they could take a shopping break or visit a destination for child-friendly fun or both. The developers wanted a cover for the play area as a way to define the space. It would also make the area useable year round in a city that can see more than 100 days of rain a year.
Architen Landrell Associates, South Wales-based tensile fabric specialists, was chosen to design and install the cover. “The purpose of the canopy was to refine the environment, make it a focal point and make it a nicer place for families to be,” says Amy Wilson, senior sales manager for Architen.
The tensile fabrics firm was brought in to design the cover for the play area after the project was well underway, so time became a factor. “We were relatively late to the process, which is not unusual with urban regeneration projects, so we had to develop a few architectural sketches fairly quickly,” Wilson says. “The design was changed and refined over a matter of weeks, but we settled quickly on double conic cones.”
From design to installation, Architen’s time frame was about five months.
Conic structures offer all-weather protection while bringing visual drama to an outdoor space. In this case, the design choice was particularly appropriate because Wembley Stadium, the civic center and other tall buildings surround the play area. At 26 feet, the height of the cover would keep the play space from being dwarfed by its surroundings.
The requirements for the canopy fabric included that it wear well in all kinds of weather and be budget-friendly. “The developers were keen on keeping the canopy looking spick-and-span,” Wilson says. “We had to consider how to mitigate for the pollution and dirt common in an urban environment.”
Inspired by nature
Architen chose PVC polyester with a unique quality: it is self-cleaning. Manufactured by Mehler Texnologies GmbH, based in Hückelhoven, Germany, the fabric employs nano-fabric technology, a process inspired by nature that washes away biological matter in the rain. The fabric coating, which features titanium dioxide (TiO2), makes the material very smooth, filling in any microscopic jags or cracks that could trap organic matter.
Typically, water wets the entire canopy during a rain and travels down the surface, leaving a trail. But with the coating, water beads up on the surface, creating large-sphere droplets that move as a single body travelling down the structure, taking dirt with it as it goes. The coating also makes the fabric a very bright white, which contributes to its long-lasting clean look. According to Wilson, the coated fabric has a life span of 20 to 25 years in this setting.
To take care of the rainwater runoff, a drainage system was integrated into the fabric structure, featuring fabric gutters around the perimeter of the canopy that transport the water to the corners. From there, the water travels through flex pipes connected to membrane plates, then down through galvanized steel perimeter posts where it is finally directed into an underground drainage system.
One of the challenges of the project, according to Wilson, was working in concert with the play equipment company to install the playground and the canopy at the same time. “By its nature, the fabric is easiest to install by laying it on the ground and jacking it up. It’s best for us if the play equipment is not there,” she says. The play equipment was large, so it was determined that the best course was to put the canopy up first and reconfigure the play equipment to fit underneath. With an open and unfinished floor surface and a fabric that is relatively easy to manipulate, the installation was straightforward.
Installing the canopy required lifting approximately 5,200 square feet of fabric onto the steel framework. It was accomplished using a 40-ton crane to position the canopy, using a unique installation and tensioning method called sand pots.
Steel sand pots were installed in the ground below the finished floor level, and two central pushup masts were inserted into these pots. As the masts were jacked up, the space beneath the masts was filled with sand, creating a surface for the steel masts to stand on. During this process, the entire canopy was pushed up into place, adding the appropriate amount of tension to the 118-foot by 66-foot structure.
While a tensile fabric cover usually does not need retensioning, if it became necessary, this method allows for the work to be done relatively easily.
Bathed in light
The head ring at the top of a conical structure is often made of steel. In this case, the client wanted the space to be light-filled and airy. To achieve this, Architen installed polycarbonate roof light domes in the head-ring space to provide natural light, while still protecting visitors from rain. In addition, the structure has lighting mounted on the center masts that down-lights the space underneath, providing warm, ambient lighting in the winter. “The PVC cover works nicely with the added lighting. There is a real warm glow throughout the space,” Wilson says.
The new play area officially opened on May 3, 2014, when it hosted popular singer Peter Andre. The day drew a crowd of 28,000 people who came out to see the British celebrity, and stayed to enjoy the playground and all the other activities Wembley Park has to offer.
Julie Swiler is a freelance writer and editor based in St. Paul, Minn.
The lotus effect
The process of looking to nature for design solutions is known as biomimicry. The self-cleaning properties of the fabric used for the Wembley Park canopy were inspired by nature—in this case, the lotus flower.
Known as the lotus effect, nano-fabric technology produces a state of very high water repellence known as superhydrophobicity. Water lands on the fabric in large droplets, just as it does on a lotus leaf. The water doesn’t saturate the surface; instead, the droplets easily run off, taking dirt particles with them.