River Legacy Living Science Center - Arlington, TX

RIVER LEGACY PARK & LIVING SCIENCE CENTER

River Legacy Living Science Center - Main Gallery

Sustainable Design

The following information is taken from River Legacy's website:

"A simple fortress of fallen leaves and broken tree limbs, crafted by the creative hands of children, served as the inspiration for the Living Science Center.

We developed the 12,000-square-foot center with the specific objective of minimizing the impact on the environment. To that end, the Center itself is a fascinating study of architecture, conservation and sustainable design.

• Three enormous red oak trees provide structural support for the roof of the building. The trees were salvaged from a city of Arlington street-widening project.
• The entrance drive was carefully routed to avoid trees and to minimize paving and vegetative disturbance.
• The parking lot is constructed of porous pavers that allow air and water to recharge the soil.
• Walkways are made of decomposed granite with an organic resin that makes them firm yet pervious to air and water.
• Restroom walls consist of tiles made from recycled crushed windshields.
• The building’s carpet is woven of fibers that may be continually recycled.
• The Center uses a gray-water system of plumbing. The underground system captures the runoff from drinking fountains and sink materials; then stores, treats and recycles it for use in the landscaped areas complementing the structure.
• Agrosoke, a naturally occurring moisture retention gel, acts as a water reservoir when added to bed and lawn soils."

Anne Alderfer - Naturalist

Our tour began with an introduction to the Living Science Center by our guide and Naturalist, Anne Alderfer.  The center has displays that discuss the vision of the architect who designed the building (Edward M. Jones) as well as samples of the materials and methods incorporated into it's construction.

(left) Anne provided us information about the local native plants along the path.  We stopped here to look at an American Elm tree that was riddled with holes created by Yellow-Bellied Sapsuckers.  A native bird that pecks holes in the bark of the trees to cause sap to flow.  The bird returns later to consume the sap along with any unsuspecting insects that might have been trapped by the sticky substance.  The large number of holes indicated that the tree, however large, was under stress or diseased.

We learned about how non-indigenous plants like the Chinese Privet (right) are invading natural areas and pushing out native plant species like Virginia Wild Rice and Inland Sea Oats.  Notice how droopy plant's leaves are.  We saw a lot of this due to the extended drought conditions and high heat in this area.  Many plants in the park are being streessed by the lack of water.

 (left) A Cooper's Hawk's nest sits empty.  The pair of hawks that migrate here annually have raised their chicks and have headed to other hunting grounds  This nest is a short walk from the Living Science Center and a great place to bird watch when the hawks are here.  River Legacy Parks are home to more than 225 bird species.

(right) Anne points out a spot on the base of a large oak tree that has started to decay.  This scar was caused by heavy equipment striking the tree during the creation of the park.  It takes years for damage like this to become apparent.  This majestic tree will not last many more years before it falls and it added to the decomposing matter on the forest floor.  It will become food for future generations of plants and animals.

For more information about River Legacy Parks or the Living Science Center click here:
http://www.riverlegacy.org/

Korwall Industries - Arlington, TX

KORWALL INDUSTRIES

Korwall Industries' manufacturing facility in Arlington, TX

 On July 30th we toured Korwall Industries in Arlington, TX and met one of the founders and owner Mr. Stan Demmick.  Korwall Industries produces Structural Insulated Panel Systems (SIPS) which are an engineered "sandwich" of expanded polystyrene foam between two sheets of oriented strand board (OSB).  The properties of this pressure-bonded panel create a structure known as a monocoque.  Mr. Demmick told us that he got this design idea from the manufacture of airplanes which are built using similar design processes.

Korwall began as a manufacturer of mobile home with paper honeycomb core floor panels and styrofoam core walls.  Even though their product was of much higher quality than the competition they were 30% higher in cost which made it difficult to sell their product.  In 1962 they moved to their current location and began marketing their panels as an alternative to stick-built homes.  Mr. Demmick said, "the lack of studs was mind-boggling to building inspectors" and they frequently had to educate officials about the integrity of their product.

Mr. Stan Demmick explains the history of Korwall Industries



The beauty of SIPS built homes is their air-tightness.  Mr. Demmick explained how a "door blower" air leakage test is done to simulate 15mph winds striking a house from all four sides at the same time.  Standard stick-built construction normally tests at 4 air changes per hour where SIPS construction tests out at 0.5 air changes per hour or a factor of 8 times less.  Because there is less air leakage there is less outside air that has to be conditioned to meet the thermostat setting inside the house.  This allows air handling units to be sized much smaller on SIPS buildings, frequently by half.  Even though SIPS cost about 5% more than conventional stick-built construction, erection time and labor is cut dramatically not to mention the savings in a much smaller HVAC unit for the same size house.  Korwall is also not limited by rainy weather the way conventional home building is because the panels are constructed in a factory not on a jobsite.  Erection of a 2000 s.f. home can be accomplished in about 2 days as opposed to weeks for stick built construction.

Mr. Demmick's grandson adds framing members to a panel

Their panels are currently constructed of a 1# density polystyrene foam core pressure bonded with a catelyzed glue to 7/16" think oriented strand board on both sides. Panels are 8' wide by 24' long in nominal thicknesses of 4", 6" and 8" standard. They will make thicker custom panels up to 10" or 12" for walk-in refrigerators with short spans.  Eight inch thick panels will clear span 16 feet without deflection under a 27 pound per square foot load.



8' x 24' x 8" thick blank panels waiting to be used

The polystyrene foam can be purchased with a 1.5" square groove at 18 inches from one side to correspond with the standard height of electrical outlets.  The groove becomes a wire race once the panels are assembled.  Korwall will install non-standard height outlet boxes and provide raceways in panels as needed.  All electrical outlets and wireways are integrated into the panels at the factor so all the electricians have to do on the jobsite is pull wires and connect terminal devices.

Glue applying machine

Korwall has tried using treated lumber in lieu of standard lumber but the panel strength was reduced by 23%.  SIPS panels are typically used just for the shell of the building (walls and roof) with the interior walls being standard construction and concrete slab on grade floors.  They can be used for floors in pier and beam construction but must be overlayed with a hard surface flooring to avoid puncturing the OSB skin.

Korwall panels carry a limited lifetime warranty.

You can find out more about Korwall here:  http://www.korwall.com/SIPs/PanelHomes/Default.htm