The intention is to begin attending DeKalb School District 428’s Facilities Planning Committee (FPC) meetings despite harboring doubts that a non-construction type could contribute much to the discussion. But now the thought occurs: Send Enviro Woman! She’ll know what to say! Such as, “LEED, or get out of the way!”
Take the case of the precast concrete vs. masonry construction debate. Enviro Woman gets up to speed pronto on anything having to do with R-values. She knows, for instance, that hurricane-vulnerable Tampa is not only sold on precast construction for its ability to withstand storm-force winds but for its average insulation values of R-18 to R-20.
“Hmm, not bad,” purred Enviro Woman in her deceptively casual way as she perused the latest promotional literature. “DeKalb’s Building Code calls for a minimum R-13 in exterior walls. But energy costs are not going down, and I know of a precast with an insulation value of R-30. It’s also the world’s most lightweight precast, which brings costs down further. And to top it off, the manufacturer is local.”
Yes, tucked into Sycamore Industrial Park is ThermalShell Technologies, est. 2001. Their innovation includes a proprietary concrete formulation and interior steel; a local example of their work is the TAILS Humane Society’s shelter. Concrete Products.com featured two of their projects in an article last year, a 22,000 s.f. banquet hall and a 32,000 s.f. community center:
ThermalShell’s three-component wall panel system — comprising a 2-in.-thick, 5,500-psi concrete exterior and a prefinished, 26-gauge corrugated steel interior panel enclosing a 4-in.-thick, polyurethane foam middle layer — was selected by the builder for its insulating properties and finished interiors contributing to ease of construction. In addition to an R-30 insulation value, the lightweight panels provided interior surfaces requiring no further treatment for the gym and mere drywall in classrooms and recreation areas. For an especially rigid roof, requiring half the normal number of joists, steel sandwich panels (constructed of two high-rib 26-gauge sheets surrounding 3½ inches of polyurethane insulation) were installed and finished with a triple-seal system to prevent leaks.
Moreover, the precast exterior offered versatility with economy. A brick liner used in fabricating the wall panels, as well as skillful color application, created a genuine brick appearance. For the reveals, custom-made components were attached to the casting table to form accenting elements. A glass-smooth finish, furthermore, was achieved to avoid inconsistencies in the finish.
Besides meeting aesthetic requirements, the panels were tailored to satisfy seismic and wind load demands. Incorporating rebar and wire mesh for structural reinforcement, the walls provide a load-bearing capacity beyond that of architectural cladding.
Erection time for the walls and roof was one month. Using a 9,000-lb.-rated, JLG 944E-42 skid steer for roof and wall placement significantly reduced the cost of installation. Lightweight components, including 31-ft. 6-in. to 9-ft. 9-in. wall panels and 40-ft. 6-in. to 8-ft. 10-in. roofing units, eliminated the need for a large crane and the attendant expense.
It appears that all construction options are still on the table but if FPC ends up being sold on the precast option, Enviro Woman believes it should definitely talk to the ThermalShell people.