Building Blitz of Habitat Homes16 Jan, 2008 By: Heather Livingston
Advance preparation and BIM software help volunteers provide accurate estimates, minimize waste, and optimize the logistics of a charitable effort for hurricane victims.
The architectural industry readily gives its time and expertise to serve community and profession, to which organizations such as The 1% Solution, Architects without Borders, and Architecture for Humanity attest. Given that passion and dedication for improving the lives of others, it seems obvious that architects providing pro bono design services to Habitat for Humanity would be a natural fit, and indeed it is. But, because of the nature of the volunteer organization, Habitat projects can sometimes linger for years, frustrating not only the architect who’s donating design services, but also the dedicated volunteers and the recipient community.
Solid Rock Carpenters is a Glenview, Illinois-based group of nearly 1,000 Habitat volunteers. Created by the Association Management Company, Solid Rock has helped more than 70 families in the Gulf Coast area since Hurricanes Katrina and Rita wreaked destruction in 2005. Initially, volunteers at Solid Rock, too, were frustrated by the lack of progress on homes they worked on, but recently the nonprofit has embraced the “Blitz Build” style, in which a home is started and completed in one rapid effort. Of course, countless hours are spent behind the scenes in design work and coordination, but once on site, entire homes are constructed in mere days.
Solid Rock’s most recent rapid-construction effort was in Bogalusa, Louisiana. After completing two homes and beginning work on a third during 10 days in June 2007 in nearby Franklinton, the team was determined to improve upon that success. In November, Solid Rock sent 50 volunteers to Bogulasa for seven days. Over the course of one week, they built five homes and completed the third home in Franklinton, a remarkable achievement under any circumstances.
|The Habitat for Humanity homes are intentionally kept simple to lend to their affordability. Above, an efficient three-bedroom floorplan from the Bogalusa Blitz Build. (Courtesy of Mark Eric Benner Architects.)|
“Originally we were going to try to get 10 homes done in five days,” said Mark Eric Benner, architect and Solid Rock Carpenters volunteer. “That would’ve been a real stretch, but they had some land acquisition issues that narrowed the project down to the final five.” Saving considerable time, money, and coordination efforts, all five Bogalusa homes ultimately were constructed in a single cul de sac. Although the constructed houses contain similar elements, no two are identical. For this project, the five houses are a mixture of three- and four-bedroom homes.
Benner explained that one reason why Solid Rock focused its efforts in Washington Parish, where both towns are located, is because the available funding for homes in that parish was set to expire at the end of 2007. “There was a mad rush to ... get as many houses done as possible,” he said. “In the previous 20 years, I think this Habitat chapter built five homes. This year, they built 17, and we represent eight of those.”
|With materials on site, the work begins in earnest. (Courtesy of Mark E. Benner, AIA, and Megan Engle.)|
|On only the second build day, the home begins to takes shape. (Courtesy of Mark E. Benner, AIA, and Megan Engle.)|
In addition to Solid Rock’s cadre of volunteers, Benner gives credit to Graphisoft’s ArchiCAD for dramatically accelerating the estimating and construction coordination of the project. “Volunteers came together on weekends and evenings to precut, lay out, and build all the walls and building components, shrink-wrapping them into neat packages for assembly by our on-site volunteers,” he said. “The ArchiCAD models enabled me to quickly and easily generate all the construction documents to be utilized by a largely unskilled workforce, while also helping to coordinate material delivery and construction sequencing to speed up the process.” Benner said that this high degree of preparedness enabled the professional and trade volunteers to move into supervisory and quality control roles, which ultimately produced more homes of better quality in less time using the same number of volunteers.
“As is typical, the benefits of computer aided design and BIM [building information modeling] are truly realized under conditions of change,” Benner said. “Our production package [comprised] a variety of home configurations, including a three- and a four-bedroom package. The mix was in flux within one week of our production build days, affecting our material quantities and destination locations. The powerful analysis tools allowed us the flexibility to respond to our changing production package.”
Whereas previous projects relied on manual estimating and coordination techniques, which resulted in inaccuracies in quantities and increases in field corrections, the use of BIM allowed quantities of materials to be accurately estimated, thereby minimizing waste. In addition, coordination of the volunteer effort was optimized through advanced preparation and efficient site usage, as well as logistics for shipping the assembled components.
|Though simple in appearance, these homes are highly functional and a huge step toward a better life for the new homeowner. (Courtesy of Mark E. Benner, AIA, and Megan Engle.)|
Although it would not have been impossible to complete the homes without ArchiCAD’s BIM, Benner believes it would have been much more difficult. “We definitely were using [BIM] to be able to maximize our efforts in terms of doing quantity takeoffs on the project and coordinating the loading trucks and getting all those things delivered to … and installed in the right spot.
“Our improvements between our June and November trips were dramatic,” he said. “Using the same number of volunteers and building days, our volunteers built two home packages for the June trip and six home packages for the November trip.”