Investing in the Future: Pulte's Switch to Panelization PATH Case Study

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Open metal web floor trusses are precisely positioned by the floor deck assembly machine After shipping and installing the concrete panels, site workers apply a moisture curing urethane at the seams of the foundation. "Because the inside of the urethane coating remains pliable, it functions like a gasket seal," says Runnels. "If ground movement occurs, the walls may move and in extreme cases may tear the skin of the urethane. When this happens, the urethane sealant skins over the seam again to maintain the seal. So you get a good gasket seal even if there is movement in the foundation. We're talking minimum movement, but in conventional pour-in-place concrete foundations, it can lead to long-term problems like cracking, leaks, and bridging." "We install 1 inch of rigid foam insulation on the exterior of our concrete foundation for optimal insulation performance and to manage condensation potential. If we do not insulate the exterior of the foundation, water may condense on the interior surface. By insulating the exterior, we move the condensate line to the outside of the foundation wall so it can drain properly, rather than allowing any moisture inside the basement. "Over the top of the foam, we do a shotcrete finish for added durability. This is done in the field, which gives it a continuous seamless appearance. When you look at our foundation, you cannot see a difference between a poured-in-place wall and the product we deliver because of the shotcrete finish. So it has the same curb appeal." A strong floor system Once the foundation walls are installed, a pre-fabricated open-web floor truss is laid. "Because they are built in the factory, we end up with a very low deflection: 3/16-inch maximum over 10 to 12 feet," Runnels says. "In addition, we get a very high deflection ratio in our floor system. Minimum code requirement is L/360. Our average is L/720. By raising the deflection ratio in the floor, we dramatically reduce the shake that occurs when someone walks up stairs. "We provide a 7/8-inch decking on the floor system. With this decking, we can increase our floor truss spacing to 32" if we have to, but we keep our truss spacing to a maximum of 24". The thicker decking also adds stiffness to our subfloor to prevent tile cracking." SIP walls "We manufacture a SIP exterior wall, which we also use in walkout areas for the foundation," says Runnels. "The SIP consists of 7/16-inch oriented strand board (OSB) that sandwiches a 1-pound-density extended polystyrene (EPS) core. The layers are adhered together by a moisture-cured urethane adhesive. We use SIPs instead of a normal stud-framed wall because the 9'1"x 24'-long SIP gives us more consistent wall insulation. At the same time, the wall has tremendous strength compared to stud framing. So we get the benefit of using the high sheer strength from the OSB, and we get energy-efficiency benefits from the foam." PREVIOUS  1 | 2 | 3 | 4 | 5 | 6  NEXT