A Passive House in Kansas City, Mo., features sandwich-panel-style walls with ten inches of precast concrete surrounding a six-inch layer of insulation for maximum energy savings. The precast panels were manufactured in-house by general contractor Crossland Construction.
The 276-unit Second + Delaware apartment complex in Kansas City, Mo., is touted as the world’s largest Passive House structure. One of the key design elements to help the project garner the designation are custom 16-in. thick sandwich panel-style precast walls.
General contractor Crossland Construction of Columbus, Kan. manufactured the precast panels at its in-house fabrication plant (Crossland Prefab).The walls consist of 10 inches of concrete sandwiched around a 6-in. layer of insulation—allowing for optimal thermal comfort and privacy.
Other Passive House design elements that are unique to both the national and local Kansas City multi-family market include triple-glazed certified windows, a Dedicated Outside Air System that draws fresh air from outside into living spaces, and a ventilation system and Variable Refrigerant Flow heat pumps that assure every unit has superb indoor air quality.
These features help the building achieve up to a 90 percent energy savings versus an average building of similar size.“Now is the time for developers to think bigger than ever before,” says Jonathan Arnold, co-developer and principal, Arnold Development Group.
A sandwich panel is any structure made of three layers: a low-density core, and a thin skin-layer bonded to each side. Sandwich panels are used in applications where a combination of high structural rigidity and low weight is required.
The structural functionality of a sandwich panel is similar the classic I-beam, where two face sheets primarily resist the in-plane and lateral bending loads (similar to flanges of an I- beam), while the core material mainly resists the shear loads (similar to the web of an I-beam).
The idea is to use a light/soft but thick layer for the core and strong but thin layers for face sheets. This results in increasing the overall thickness of the panel, which often improves the structural attributes, like bending stiffness, and maintain or even reduce the weight.