©2013 Green Building Advisor. From The Taunton Press, Inc., publisher of Fine Homebuilding Magazine.
I'm an architect working on the remodel of a single-family dwelling in San Francisco (Climate Zone 3C). My client wants to maximize the city view, so steel will be used for a rigid steel frame at the view side of the building, for the structural frame of a cantilevered deck, and for posts and beams at a number of exterior walls. The cantilievered steel deck will be welded to the rigid steel frame (no gap for a thermal break material), and the engineer has called for steel beams to be welded to the rigid steel frame at the ceiling of the interior opposite the deck beams to offset the torsion loads of the deck beams. What do you recommend to address the thermal bridging issues, and the related potential for condensation at the interior, for these conditions? To address these conditions, I anticipate that spray foam insulation will need to be used at the interior steel members that are linked to the cantilevered deck, and perhaps thin rigid insulation on the exterior sheathing where steel members occur, but I'd appreciate any suggestions.