Penn State University’s GridSTAR Center, located at The Navy Yard in Philadelphia, is a groundbreaking, new campus offering smart-grid-focused construction workforce training, building performance testing, and energy management research. Consisting of a net-zero energy demonstration home and a solar power training facility, the Center’s design showcases some of today’s most high-performance, contemporary energy-efficient building products. To produce the desired results for the project, Penn State partnered with several leading sustainability-focused building product manufacturers.
To create a sustainable, energy-efficient foundation for the GridSTAR Center net zero demonstration home, Penn State consulted North American Specialty Products (NASP, formerly CertainTeed Corporation’s Pipe and Foundations Group) for assistance. NASP hired Philadelphia architect Steven Gnau to design a well-insulated foundation that, along with equally well-insulated above-grade wall, roof, and attic-ceiling assemblies, will help retain heat and cooled air inside the home during any smart grid events or power outages.
Gnau’s design called for thermal isolation of the modified crawlspace foundation floors and walls from the surrounding soil with interior and exterior insulation. Interior comfort is improved by the thermal mass provided by the concrete foundation and use of 2 to 3 inches of coarse gravel fill.
The design also gave special attention to groundwater and radon evacuation. Since net zero energy homes typically have airtight construction to prevent energy-wasting air leaks, they can be subject to poor indoor air quality and moisture problems if foundation moisture is not managed effectively and proper ventilation is not provided. A multifunctional foundation drainage and waterproofing system, including a sump pump and radon vent, is critical to the building’s durability and air quality.
The project’s general contractor, Commercial Line & Electric Inc., of Glen Mills, Pa., hired three contractors to install the high-performance custom-designed foundation due to the different installation skills required. QCI Inc., of Aston, Pa., was contracted to form and pour the foundation, while Old Philadelphia Associates Inc., of Philadelphia, was hired for the waterproofing. Rounding out the team was West Chester Insulation Inc., of West Chester, Pa., hired to install closed-cell spray foam (SPF) insulation throughout the crawlspace.
QCI excavated 3 to 4 feet for the foundation footing and installed micropiles and Form-A-Drain. Form-A-Drain is a leave-in-place, slotted PVC concrete footing form that also serves as a foundation drainage system and a component of a sub-slab perimeter radon reduction system. Since it is left in place after the footing is poured, it saves contractors the extra labor of stripping traditional wood or steel forms and installing drain tile and a radon evacuation system. The QCI crew used steel D-pins, drywall screws, and wooden stakes to level the system and added Schedule 40 steel sleeves for crossover piping. They then put up the foundation walls.
Working with Form-A-Drain for the first time, the contractor was impressed by how easily it installed and the steps that it saved. “I think it’s a good system, especially for applications like this,” says Jason Blose, project manager for QCI. “It’s user-friendly and easy to work with. Plus, we didn’t have to strip forms, which saved labor and cut down on jobsite waste. And, we didn’t have to go out and buy the perimeter drain material and put down fabric and stone again.”
Old Philadelphia Associates installed 2 inches of ThermaEZE in the foundation walls for an additional thermal resistance of R-10. ThermaEZE consist of expanded polystyrene foam insulation panels that are set into wall forms prior to the concrete pour and held in place by a web structure that weaves throughout the concrete.
Sealing out water, bridging cracks
The contractor also installed an air-gap waterproofing membrane over the gravel fill before the concrete was poured to provide a moisture barrier to protect the SPF insulation. The material used was NASP’s Platon, which was also attached to the exterior of the foundation walls. This material is a dimpled 24-mil high-density polyethylene that provides wall and under-slab moisture control for all types of foundations and isolates living spaces from floors that otherwise can become damp. The product seals out water and bridges cracks in poured concrete, ICF construction, and masonry block walls.
Finally, the crew installed sill flashing at the top of the foundation exterior walls for extra protection from leakage. The NASP EnergyFlash sill flashing remains in place protecting at-grade insulation during and after construction.
Like QCI, Old Philadelphia Associates was working with these foundation products for the first time and was pleased with the guidance the crew received from NASP customer support. “It was basic instruction, but he helped me out a lot,” says Jim Helveston, project manager for Old Philadelphia Associates. “I’d installed similar materials before, but never these particular products. They were actually pretty simple to install, and should therefore be an economical option for most end users.”
West Chester Insulation applied 2 to 2-1/2 inches of closed-cell SPF insulation along the floor and walls of the crawlspace, adding a thermal resistance range of R-13 to R-16.3.
The job ran smoothly, and GridSTAR Center opened to the public this past October to rave reviews. As part of Penn State University’s Center for Sustainability in the school’s Architectural Engineering department, the campus offers a variety of for-credit and non-credit courses for college students and building, architecture, and engineering professionals.
Mark DaSilva is manager of product development and marketing for North American Specialty Products.