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HomeMy WebLinkAbout02 Church Building Assessment IMEG 11_20_24 January 3, 2025 Ms. Jillian Bertelli WAM Dev Group, LLC 140 E. Main Street, Suite G Bozeman, MT 59715 Re: Structural Assessment – 112 South Church, Bozeman, MT Dear Ms. Bertelli, On November 19, 2024, Nathan McBride from IMEG Corp. along with Jillian Bertelli and Scott Holton from WAM Dev Group, LLC, conducted a site visit to observe the existing structure. The purpose of the site visit was to assess if there were structural issues that would be considered unsafe in relation to IEBC 2021 Section 115 of the building code, which is the current code adopted by the City of Bozeman and the State of Montana. The following issues were noted as not compliant with the current code and would constitute an unsafe condition if code loads were applied to the building. The scope of work for this building assessment did not include a detailed analysis of the existing structure. This cursory observation was of a visual nature limiting destructive methods. Small holes were cut into drywall at various locations to observe framing. Every condition or potential structural condition may not have been noted. Observations made and probable conclusions reached were based on visual examination and evidence, without the benefit of direct observation of some structural elements. In some cases, exact determination of workmanship and structural integrity cannot be made without destruction of interior or exterior finishes. Building Description The two-story structure was constructed in 1920 with an addition added in 1925 per Montana Cadastral website. The structure is constructed using typical light-frame wood construction. There is a full basement under the original residence. Floors are constructed using 2x8 @ 16-24” OC. The roof of the structure is constructed using 2x4 roof rafters at 24” OC with a tension tie (collar tie) below the ridge. Unsafe Conditions: 1. Existing 2x8s are spaced between16” and 24” on-center floor joists with a span of 15’-0”. These joists are 27-90% overstressed for the dead load in the system and the 40 psf code prescribed live load in the IBC 2021 for residential occupancy. See Figure 2. 2. Floor joists are buried directly into the concrete foundation walls with no moisture/vapor barrier separating the concrete from wood framing, allowing moisture to wick through the concrete wall and into the floor joist. This moisture will cause the joist to rot and degrade over time causing a bearing failure at the basement wall connection. See Figure 3. 3. There is no plywood sheathing on the exterior to provide lateral resistance to lateral forces on the building caused by an earthquake or the wind. This eliminates the ability to transfer the shear forces down to the foundation, which could result in racking of the entire structure. TO: Ms. Jillian Bertelli IMEG #24007134.00 DATE: January 3, 2025 Page 2 of 2 4. No anchor bolts are installed to connect the wood framing to the concrete foundation wall to resist lateral forces applied to the building caused by seismic or wind events. With no anchor bolts there is potential for the building to slide off the existing foundation. See Figure 3. 5. A multi-wythe masonry chimney extends from the basement up through the entire house and extends 5-6 feet above the roof plan. The chimney is not braced against the existing framing and is likely to collapse in an earthquake and fall through the building. The mortar is brittle and has spalled away from the bricks. See Figures 4 and 5 6. The roof is framed with 2”x4” roof rafters at 2’-0” on-center with a tension tie (collar tie) nailed to the rafters several feet below the ridge. A quick visual analysis model of the roof framing was modeled with dead load of the structure and 41 psf snow load per the City of Bozeman. The analysis revealed the members were 200% over-stressed and could result in failure during a large snow event. 7. The existing basement wall had damage exposing most of the wall thickness and no reinforcing was observed in the area. Without reinforcing in the wall it does not have the ability to support the design lateral earth pressures typical for this type of construction in downtown Bozeman. If the code prescribed lateral earth pressures were to develop the wall would develop large cracks potentially leading to complete failure of the basement wall. Applied loads during a seismic event could be catastrophic. See Figure 6. 8. The stair stringer is notched down to 2” at the treads, which results in stringer being 200% over- stressed for code related live load of 40 psf in a residence. See Figure 7. 9. The secondary structure on the property is constructed using a multi-wythe masonry wall and is already showing signs of distress with cracks forming in the mortar joints. Unreinforced brick masonry walls are not utilized in the IBC 2021 for the seismicity levels found in Bozeman and have a history of extensive damage and collapse during a seismic event. See Figure 8. Summary Based on the site observations, the building is deficient and unsafe for occupancy and should be demolished. Thank you for the opportunity to be of service. We trust the analysis adequate for your needs, but should you have additional questions please contact the undersigned. Sincerely, IMEG Corp. Nathan McBride, PE Client Executive nathan.d.mcbride@imegcorp.com Phone: (406) 586-2739 NDM/jah Enclosures: Figures of existing structure Sincerely, Nathan McBride 1/3/25 112 S Church, Bozeman, MT 59715 Job #: 24007134.00.00 Figure 1: Existing structure looking East Figure 2: Metal deck corrosion Figure 3: Joist embedded in woncrete wall and no anchor bolts 112 S Church, Bozeman, MT 59715 Job #: 24007134..00 Figure 7: Stair Stringer Figure 4: Chimney above roof Figure 6: Concrete wall damage Figure 5: Chimney in basement 112 S Church, Bozeman, MT 59715 Job #: 24007134.00 Figure 8: Secondary unreinforced masonry building