Article No: 242

2008-08-01 17:46:24
Rafiki Village
By:


 
Earlier this year, Greenblock Worldwide Corp. announced that it had been awarded the insulated concrete form (ICF) product and installation contract for the new home offices of The Rafiki Foundation, Inc. (rafiki-foundation.org). The 57-acre Rafiki campus will feature 13 buildings constructed with more than 25,000 square feet of Greenblock ICFs.

The Rafiki Foundation is a 501(c)3 non-profit Christian ministry, founded in 1957 by Missionaries Rosemary Jensen and her husband, Dr. Robert Jensen, that builds and operates orphanages in ten English-speaking countries in Africa, including Ethiopia, Ghana, Kenya, Liberia, Malawi, Nigeria, Rwanda, Tanzania, Uganda, and Zambia. Within these ten countries are more than 24 million orphaned boys and girls, the innocent victims of famine, civil war and disease—mainly the HIV/AIDS pandemic.

Rafiki provides housing, meals, clothing, education, Christian nurture, and medical care for its children from the time they arrive, at the Rafiki Villages until they reach young adulthood. It is the mission of the ministry to raise the next generation of African leaders from among its children with the hope that they may be able to lead their countries out of the cycle of devastation that has gripped the African continent for the past three decades. Therefore, children are not adopted out of their country.

Sustainable, energy-efficient and structurally superior buildings were mandated by the design architects for this project, which led them to the selection of Greenblock ICFs for the exterior wall systems.

“Rafiki Foundation has constructed buildings of superior quality and energy efficiency in all its projects in Africa, so when it was time to build our new home office in the United States we wanted the same thing,” says Steve Kranz, Rafiki’s director of home operations. “It was a perfect fit for us to choose ICF construction, knowing that it would provide beautiful and very energy efficient buildings.”

John Riddle, Central Florida territory manager for Greenblock, says the sustainable and energy-efficient ICF designs for these structures will lessen the effect on energy use within this community and become a long-lasting benefit for the Rafiki Foundation as the maintenance and operating costs will be lower than wood-frame construction.

Mark Construction Co. of Longwood, Florida, is providing construction management for the project, which began in late February and will conclude in early September. The Rafiki Foundation has already begun relocation of staff members form their current home office in San Antonio in anticipation of this construction project. Upon completion of the home office complex, approximately 15 full-time employees will be working from the Rafiki campus where hundreds of volunteers will receive training and preparation instruction before leaving for Africa to provide services directly to orphaned children at one of their ten Rafiki Villages located in ten African countries.

With its roots in Europe for more than 45 years, today’s Greenblock has built a significant number of projects, ranging from stem walls, basements, single, and multi-story residences, apartments, condominiums, towers, and even swimming pools. Government agencies, schools, commercial, and light industrial companies are now recognizing the superior features of insulated concrete form-built structures and are beginning to utilize them for environmental, disaster resistance, and energy conservation benefits.

ICF EFFICIENCIES
When the designers took on the task of creating a new home office complex for the Rafiki Foundation, they were charged with developing a plan that would evolve the 57-acre campus in Eustis, Florida, into a working environment that blended with the natural surroundings, but also would provide sustainable, energy-efficient, and safe structures to house the hundreds of volunteers and staff who spend time on the campus each year.

With the input and support of the construction management team at Mark Construction, the clear choice became to design and construct the complex using ICFs.

Greenblock’s versatility and strength appealed to the building team’s vision. “The 12-inch-tall design and the web ties spaced at every 6 inches was areal deal-maker for us and the architects on the project,” says Todd Jorgensen, president of Mark Construction.

“We knew that the ability to design the structures around the needs of the Rafiki team mandated an ICF that is designed for superior strength as well as ease of installation,” says Jorgensen.

Ease of installation was readily apparent as the ICF installer, Insulated Concrete Walls Inc. was well ahead of the scheduled installation timeline. In three weeks, the company had assembled, poured, and completed seven of the 13 campus structures, according to Randy Abrego, project superintendent for Insulated Concrete Walls.

“The Greenblock forms are easy to assemble and hold up very well to the 3000 PSI concrete we fill them with,” Abrego says. “We’re able to pour multiple buildings on the same day with our crews quickly and easily moving from building to building.”

The ICF being used for this project is the Greenblock 2-4-2 4-inch core product. The 2-4-2 ICF has all the strength of the wider core ICFs, but has been specifically designed to compete as an alternative to the commonly used CMUs found on many projects in the southeast United States.

John Riddle, territory manager for Greenblock, says the 2-4-2 ICF has an overall width of 8 inches, which allows designers, architects and installers to efficiently substitute ICFs into a job that may have already been designed for CMU walls. “This ability to easily substitute, without having to redraw plans or change the design, has allowed homeowners and commercial developers to make the energy-efficient and storm-resistant switch to building with ICFs,” Riddle says.

SUB-FRIENDLY FOR LAST-MINUTE CHANGES
While the wall assembly is the most noticeable segment of the construction process, it is the dry-in stage that really puts the project on schedule and opens the door for the remaining trades to move efficiently toward project completion. In fact, given Central Florida’s wet summer season, it can be considered the most important segment of the construction process—one that really keeps the project moving forward.

The Greenblock walls at the Rafiki Foundation Home Office complex were finished nearly three weeks ahead of schedule. The fully assembled solid concrete, steel-reinforced ICF walls allowed Mark Construction Co. to move forward on the dry-in stage of the project well ahead of schedule.

The Greenblock ICF walls easily accepted the steel roof truss systems. The roof structures were craned into place and secured using screws, bolts and hurricane strapping. “The flat smooth surface on the top course of the ICF walls made for a quick and easy attachment of the roof trusses,” says Steve Kranz, director of home operations for the Rafiki Foundation. “No special bracings or shims were needed and the trusses were easily aligned with the previously embedded hurricane straps as required by local code.”

Once the roof structures were completed to include the standing seam metal roof panels on the steel roof trusses, the door and window installers moved into action. The hollow metal frames for the doors were braced into placement, square and plumb, during the wall assembly.

“Insulated concrete form walls provide for efficient assembly of hollow metal door frames during the stacking of the wall systems,” says John Riddle, territory manager for Greenblock. “The frames were braced and secured by a professional door installer and the ICF walls were built around the frame.” During the placement of concrete into the ICF wall cavity, the concrete pump crew also placed concrete into the metal frame cavity of the door, effectively securing the doorframe to the wall. “Again, another step-saver due to the efficiency of ICF walls,” Riddle says.

When the bracing was removed, the door installation team moved in to complete the hanging of the solid exterior doors. Due to proper bracing and secure assembly into the solid concrete walls, the doors were quickly and efficiently hung with each door frame maintaining its square dimensions making the door swings level and closures meeting all alignments.

While the door installation team was making good time on their segment of the dry-in process, the window installation team began assembling the insulated low-e windows and frames into their prepared openings. Eleven window openings were created using the V-Buck vinyl bucking system. The precision cut V-Buck was assembled by Insulated Concrete Walls, Inc. (ICW), the ICF installation team on this project. The V-Buck system is placed into the ICF wall assembly prior to concrete placement and is secured into the structure during the concrete pour. Bracing of the V-Buck assures square dimensions and the ICF wall alignment system keeps the window openings plumb along with the ICF walls.

However, the true versatility and adaptability of ICF construction showed when, after the concrete had been placed in all the walls, the Rafiki Foundation team toured the site and decided they preferred the window openings to be lowered by several inches to allow for a more panoramic view of the scenic, 50-plus-acre complex.

After consultation with the project’s structural engineer and designer, it was decided that the windowsills would need to be lowered by cutting through the solid concrete walls. The ICW installation team said “no problem” and immediately went to work to quickly and efficiently make the changes. Once the window openings were completed, the window team moved into action and assembled the window units into place by securing the required attachments directly into the V-Buck system.

Kranz says proper bracing made for precise window dimensions, which allowed the windows to be easily installed with only the required shims needed to align the windows square into the openings. “This, along with the quick response of the ICW installation team, really helped us stay on schedule with the project.”

During the window and door placement, the contractor for exterior wall application was able to move forward with the selected stucco wall covering. The stucco application was placed using “traditional” application methods—paper-back wire lathe and a multi-coat application of the cementious stucco finish. The ICF walls were ready for exterior application immediately upon the removal of the wall alignment systems from the wall assemblies.

Riddle says there was no need to wait for the insulation installer or hold up the stucco applicator while the vapor barrier was being applied. “Another benefit of ICF walls is that the insulation is part of the wall forming system. Our expandable polystyrene panels provide a thermal envelope of R-17 in the walls, but perform at an R-40+ due to the lack of air infiltration and thermal capacity of the solid concrete core. And, the exterior panels also provide the vapor barrier needed to withstand the moist, humid outside environment found here in Central Florida.”

The paper-back wire lathe was applied directly to the exterior polystyrene foam panels using the Greenblock web ties which serve as the embedded furring strips. These web ties are located every 6 inches and provide a vertical alignment to securely attach any exterior wall coating system—including the multi-coat cementious stucco being used on this Rafiki Village Home Office complex. The stucco applicator applied decorative raised panels around the window and doors and continued the stucco application from grade to top-of-wall—thus assuring a moisture resistant, insulated exterior wall, complete with the decorative finishes to create visually appealing wall structures throughout the complex.

With roof, doors, and windows in place and all installed with normal construction methods in the ICF walls, the dry-in stages of this project are being completed ahead of schedule and within budget.