The original exterior wall assembly of the Environmental Science Building is a durable brick veneer, air space, 1” rigid foam insulation board, damp proofing, 8” concrete masonry unit back-up wall, 3⅝” metal studs with fiberglass batt insulation, and painted gypsum wall board. The brick was manufactured in South Carolina, 780 miles from the project site. An alternative exterior wall assembly could consist of recycled brick, air space, mineral wool insulation, self-adhered sheet-applied weather resistant barrier, CLT panel, metal studs with mineral wool insulation, and painted gypsum wall board. Vertically oriented CLT panels obviate the need for perimeter columns (as below). A total of two inches of mineral wool insulation would achieve the code minimum of R-7.6 for mass wall construction in Climate Zone 2.
The secondary wall assembly, used to enclose the mechanical penthouse, is composed of profiled aluminum panels, ¾” exterior grade plywood, 6” metal stud with fiberglass batt insulation, ⅝” gypsum wall board. In an alternative assembly, the back-up wall again could be CLT panel. Emissions from aluminum production are among the highest by weight of all building materials, even though most sheet products contain at least 60% recycled material. Zinc production emits among the lowest amount of carbon of all building metals, and is also recyclable. A possible alternative assembly might consist of profiled zinc panels, ventilation mat, mineral wool insulation, self- adhered weather resistant barrier membrane, CLT panel, 2” metal studs with mineral wood insulation, gypsum wall board. There are two main roof assemblies present at the ESB. The striking profile of the building is achieved with the design of a figural roof, part of which is curved on a seventy-five foot radius sheltering the mechanical penthouse (below) . The assembly consists of standing seam coated steel roofing, thirty pound building felts, gypsum sheathing, vapour barrier, 3” rigid foam insulation, and 3” metal deck supported by structural steel. The low-slope roof assembly is made up of a single-ply EPDM membrane and tapered foam insulation on a concrete slab.
Waechter Architecture
Cross-laminated timber used in wall assembly
There are a number of suppliers of recycled brick in New Orleans. Salvaged brick has been available for years. Using it for a building like the ESB presents some challenges. Assuming relatively easy sourcing, the primary considerations are related to performance and aesthetics. Usual performance concerns are freeze-thaw vulnerability, not a concern in New Orleans; strength and water absorption, as there are no standards for salvaged brick; and the potential for efflorescence, which exists with new brick, as well. Although there may be aesthetic concerns with inconsistent color, texture and size, the wear and patina of reclaimed brick imbues a building with what Aloïs Riegl calls ‘age-value’, an emotional resonance with the natural processes of decay. While this may not map precisely to a building whose function serves scientific discovery, it could be seen as a forthright expression of the ongoing polycrisis (as below).
Wilson Architects
above: Environmental Sciences Building, detail of the curved aluminum panelled roof enclosing mechanical systems.
left: Ranelagh Multidenominational School, Dublin, Ireland by O’Donnell+Tuomey. Reclaimed brick has the potential to add age- value to a material that could come to express a response to the ongoing climate crisis.
O’Donnell + Tuomey
24 on site review 48 :: building materials
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