Green to Deep Green with Energy Efficient Straw Bale Eco Center

Screen Shot 2015-04-16 at 10.24.11 AM2014 Cool Congregations Challenge Winner

The Eco Center at Ferncliff Camp and Conference Center
Little Rock, AR
Faith Tradition: Presbyterian

Cost Savings: $7,626 annual savings
CO2 Reduction: 319 metric tons CO2 per year
Energy Savings: 956 kWh/year
Reduction in CO2 footprint (over standard construction): 95%

Ferncliff is a summer camp and year round conference center connected to the Presbyterian church but open to any and all. The challenge was to create a solar-powered Eco Center — a creatively green building on the campus to serve as: a hands-on classroom for Ferncliff’s Solar School; an adult-friendly lodge for meetings and hands-on work all four seasons, and; a summer camp for youth to engage in hands-on experiential learning about caring for creation.

The new net zero Eco Center opened in 2014. The 5,300 square foot Center features straw bale constructed walls, recycled floors, six bedrooms, sleeping space for 24 guests, meeting space for 100, and built primarily with volunteer labor. Its walls are made up of 1,200 bales of straw plastered inside and out with three coats of Natural Hydraulic Lime.  NHL is more environmentally friendly than cement in the way it is produced, allows the building to “breathe,” requires no expansion joints, and grows stronger over time.  Color was premixed in the third coat.  The Eco Center took 600 batches of lime mortar applied by hand over four months.  The R-value of these walls would be around R-33 whereas the R-value of a typical new home today is R-13 to 15.

The frame of the building is a steel building manufactured by Pinnacle Structures and the straw bales fill in the walls between the beams.  The bales themselves do not bear the weight of the building.

The building is heated with a radiant floor heating system in the slab.  About 3,300 feet of PEX tubing snakes through the floor in serpentine lines about 14 inches apart and divided into four zones.  Water with a glycol mixture is heated by a wood fired furnace/boiler outside the building and circulated through the slab which heats the building.  It takes only 7% of the energy from the buildings solar panels to run the circulation pumps.

The Eco Center’s electricity is a net-metering system with 12 solar panels each producing up to 250 watts for a total of 3 kilowatts.  Excess energy is feed back into the grid for credit.  The building as a “solar chimney” consisting of two 18” diameter tubes inserted through thThe tubes are painted black so that as they absorb heat from the sun, they will naturally pull air up and through the building by convection thereby ventilating the space.  The roof is white to reflect heat then has two layers of insulation underneath.  The first is a double backed aluminum foil that deflects 90% of the heat and the second layer 1” Styrofoam that you can see.

Since cement extracts a high cost on the environment the staff decided to not extend the slab into the four largest bedrooms but to come up with alternative floors made from locally available, discarded materials.

One floor (room 41) is made from salvaging used conveyor belts that came from Arkansas Kraft paper mill and Granite Mountain Quarry.  The belts were cut into smaller tiles, glued to donated shade material and laid over compacted gravel.  It is dubbed “the Rubber Room.”

A second floor (room 42) is made from paper mache.  AmeriCorps NCCC volunteers made a large paper mache maker for this project.  Newspaper, glue and wheat paste make paper mache and color is added.  The “stones” can be made into any shape and you can see their creativity in the floor.  The grout is also paper mache and then it was sealed with a water-based polyurethane.  This room is called “the S’more Floor” since the colors resemble graham crackers, marshmallows and chocolate.

The third large bedroom (room 45) is made using several thousand beer bottles and named the “Beer Bottle Bottom” room.  These are whole, empty bottles inserted in 4 inches of sand which is then tamped and 3-4 inches of mortar added.  We would like to thank all our volunteers who enthusiastically responded to our plea and emptied a six pack or two for us.  Actually Pizza Café and the Howl & Thirst Bar and Grill were kind to give us their empty bottles along with a couple trips we made to Waste Management’s Recycling Center.

The fourth floor (room 46) is made from thick rocks that maintained the terrace around Ferncliff’s pool that is being replaced.  Rather than let the rocks get buried as rubble they were given new life for this floor and mortared in place.  Just for fun a stepping stone in the form of a clock was added so it is called the “Rock Around the Clock” room.  The smaller stepping stones were made by students from Jonesboro’s Westside Middles School when they came to Ferncliff for several years of healing camps after their school shooting in 1998.

Other “green” features include dual flush toilets, a waste water system that uses one half the land normally needed for a leach field,  creative reuse of materials (notice the door stoppers from scrap lumber and conveyor belt pieces), LED lighting, water saving fixtures, fair trade coffee from Westrock coffee, etc.  The cedar posts along the entrance walk came off Ferncliff’s 1200 acres.

The finished cost of the building will be about $65 per square foot.  Andrew Morrison of knows of no straw bale building that is larger. Our internet search has not found any therefore we believe Ferncliff’s Eco Center to be the largest straw bale walled building in the country. ” We were inspired to build something that made a statement about our values. We were also inspired to build something that would make others think about how they could change their lifestyle to take better care of creation,” says the Rev. David Gill, Executive Director, Ferncliff Camp and Conference Center.

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