Bernie Nimer, Dave Seton Mayfair Hotel Development Corporation

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1 SITE INVESTIGATION REPORT NO. S1r1 PROJECT: The Mayfair Hotel PROJECT NO: ATTN: Bernie Nimer, Dave Seton Mayfair Hotel Development Corporation PREPARED BY: Cory Zurell, PhD, P.Eng. DATE: 13 April 2015 As requested, we visited 11 Young St. and King Street West in order to assess damage caused by a watermain break that occurred under Young St. during this past weekend. Our findings are as follows: Observations The watermain break occurred under Young St. about halfway along the Young St. elevation of the existing building. Sidewalk slabs have heaved and we understand that probing beneath the slabs indicates a void of over a metre deep in the worst affected area. We understand that the basement flooded over the weekend, with the water depth reaching the underside of the ground floor joists in some areas. The water pressure appears to have opened a horizontal slot in the foundation wall. It is located in the room housing the water

2 service in the basement. We hypothesize that a sufficiently fast stream of water was able to leak in perhaps beside an existing water pipe, and subsequently eroded the wall, creating the slot. The slot is between 1m and 1.5m wide. The basement floor is now covered with a significant amount of sediment varying up to about a metre within the water service room. From inside the basement water service room daylight can be seen through the slot in the foundation wall. Close to the damaged foundation wall is the masonry pier previously identified as being deficient and potentially unstable. It was temporarily shored during demolition of finishes however the area must be treated with caution to prevent further degradation. The basement of King was reviewed. There was no apparent structural damage to this building; effects were limited to water damage of finishes and sediment covering the floor. Conclusions & Recommendations The portion of foundation wall in the water service room has been compromised and the exterior load bearing wall above has been undermined. The wall directly above the slot does not appear to be in imminent danger of collapse; the masonry is arching over the slot. That said the wall above the slot should not be left unsupported for an extended period of time. blackwell.ca Page 2 of 5

3 Any work performed in this area either inside or outside of the building must be done with great care. Adjacent to the washed out area is the deficient masonry pier. It was temporarily shored however extensive work in this area could result in further damage. This pier should be further secured prior to work being carried out on the sidewalk and subgrade. The condition of the outside face of the foundation wall at the water service room is unknown. Vibrations could further damage these areas. Should repairs of the sidewalk be undertaken by the city, we recommend that the sidewalk slabs requiring removal should be extracted without imposing vibrations in the area; jackhammers could cause further damage. Exterior backfill should be carried out with lean concrete or crushed stone so that compaction of granular materials is not required. Prior to backfilling adjacent to the building, the foundation wall should be reviewed once it is exposed to view to assess any potential damage. Regarding repairs to the existing building, as previously noted in our condition survey, dated 15 December 2014, work inside the building should be limited if at all possible. Several areas of framing, including in the area of the stair to the basement, are compromised some severely. Movement of equipment to assist in the cleanup of the basement and any repair of the foundation wall needs to be reviewed and shoring will likely be required to ensure safe access. Followup Subsequent to the above, we attended the site to discuss the issues with the City of Kitchener Building and Utilities departments and determine a possible sequence of addressing the damage caused by the watermain break. As noted above, the deficient portion of the masonry wall (item in our report dated 15 December 2014) adjacent to the damaged foundation should, in our opinion, be secured prior to any work being carried out on the sidewalk and subgrade. Without shoring the wall is currently unsafe, and subject to potential collapse under reasonable loading conditions. To achieve a safe structure in this location, we anticipate that needling and shoring the wall at approximately the second floor level would be required in order to repair the affected masonry between the ground and second floors. The following issues present themselves based on possible sequencing of work: blackwell.ca Page 3 of 5

4 Needling of the wall to install shoring will necessitate drilling or coring of the existing masonry. This work would cause vibrations that may be detrimental to the deficient portion of wall, creating a significant risk and hazard to workers performing the work. The sidewalk adjacent the building in this location, and for a significant area to each side, has been undermined. The roadway may be partially undermined as well. Shoring could therefore not be installed without lifting and remediating the areas under the sidewalk. As already noted, lifting and restoring the sidewalk would pose a significant risk and hazard to workers performing the work given the condition of the noted masonry wall, in particular, and of the building structure in general. The above noted conditions create a stalemate. As noted in our report of 15 December, the existing building has severe structural deficiencies and is of little structural value. Work necessary to repair the new damage caused by the watermain break is dependent upon repairs that, themselves, create a significant risk and hazard to carry out. Additionally, the balance of repairs necessary to renovate the building and bring it up to code, are not, in our opinion, viable given the current state of the structure. Based on the current conditions, and the risks associated with executing repairs at this time, it is our opinion that the building should be demolished to mitigate the risks to potential workers and to the general public. We trust that the above summary is sufficient for your current needs. Should you have any further questions, please do not hesitate to contact our office. Best regards, blackwell.ca Page 4 of 5

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