Ratify Emergency Contract - State Theater Roof Repairs Proj No 125-030 - Slatile Roofing (2)

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State Theater Structural Review March 20, 2025 WWW.MAGNUSENG.COM Page | 2 In general, the cast-in-place concrete floor and balcony structures do not currently show signs of spalling, leaching or cracking. The foundation system appears to be performing adequately with no observed signs of settlement or foundation cracking. The masonry walls exhibit signs of spalling and delamination, generally around roof drain piping that has been severed or otherwise damaged (Figure 4) or areas or massive water intrusion through the roof (Figure 5). Local corrosion is visible in select areas of the structural steel in the roof structure (Figure 6). More severe corrosion and delamination were observed in the structural steel support at the low end of the side balconies in the theater space, specifically the south balcony, which is an area of high moisture exposure (Figure 7). Recommendations Roof Deck / Water Intrusion The immediate step for slowing the continued deterioration of the structure is addressing the large failures of the roof deck structure and roof drainage system. Gypsum roof decking is highly susceptible to deterioration when exposed to moisture which is addressable only through replacement. Aerial photos provided by KAP reveal several areas of the roof in which the roof membrane is not adhered to the structure and multiple areas where there is evidence of water ponding (Figure 8). Areas of water ponding generally occur near roof drains that are either currently blocked or have previously been blocked for a sustained period of time, or at areas where the roof membrane is not adhered to the roof and has bunched up, thereby not providing a uniform drainage plane for water to travel. Keller’s 2012 assessment noted several areas in which signs of water penetration through the roof deck were present, including the area on the north wall where the large hole in the roof deck has developed (Figure 9). Several other areas of the roof deck, particularly around the perimeter of the building (note, the underside of the roof deck at the interior of the building was inaccessible for this assessment) are exhibiting very similar signs of deterioration (Figure 10). While it is generally believed that the roof deck away from the low points around the perimeter of the building is in better condition in terms of deterioration due to moisture intrusion, it is very likely that local areas of roof deck around roof penetrations will need to be replaced in a similar fashion. Deterioration of plaster ceiling construction in the vicinity of roof vents and damage to roof vents evident in aerial photos (Figure 11) are indications that water is getting into the structure at these points as well and similar roof deterioration to that observed around the perimeter of the building should be anticipated. Further, the lifespan of a gypsum roof deck is approximately 50 years if the system is well-maintained and kept free of moisture. Given the apparent neglect of the building as a whole and the age of the structure being over 100 years, we recommend a thorough inspection of the complete roof deck to identify local areas of weakness and that testing be done to confirm the roof deck possesses adequate fastener pullout capacity for the roofing material applied, which may be a root cause of some of the roof membrane adherence issues currently present. At a minimum, we recommend replacement of the gypsum roof deck around the entire perimeter of the building from the exterior wall to the first roof purlin (approximately 8 -ft from the perimeter wall). One possible approach to this replacement that would best maintain continuity in the roof system would be a gypsum roof deck that would consist of steel bulb tees spanning from the exterior wall to the first roof purlin and spaced approximately at 24 -in to 32 -in with a gypsum form board laid between the bulb tees that would support a 3” layer of poured gypsum reinforced with a welded wire mesh. Another option for roof deck replacement around the perimeter would be to use a more modernly conventional corrugated metal roof deck spanning from the exterior walls to the first roof purlin, similar to the bulb tees previously described (Figure 12).