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�� gr��• '`: Boatwrignt Engineering Inc August 15,2016 _ e, saww+F 74'.? f2 ST ,A,Ei/ O 'v.']C:_ Heidi Bell o n - City Manger '''369 9225 363 .L51 City of Donald PO Box 388 Donald,Oregon 97020 Re: OLD CITY HALL ROOF EVALUATION 10790 MAIN STREET SE Dear Heidi, I visited the Old City Hall structure on August 4,2016 at which time I made observations and took measurements and photographs of the existing roof support system. I have also reviewed the letter provided by Pacific Northwest Engineering,Inc.,dated August 5,2016,to Shaylinn Construction,LLC,the roofing contractor. While various statements are made in the letter,the engineer does not provide any calculations to support his findings. I have evaluated the current roof load on the old City Hall structure. This assessment was requested after 1/2-inch plywood and composition roofing was added without the removal of two previous layers of roofing materials. I have attached a sketch which numbers the individual rafters with No. 1 being on the south and No. 14 on the north.The sketch also provides letters for the different rafter construction configurations. The outside dimensions of the structure measure 20.39 feet by 26.29 feet. The north wall,which is on a short side of the building,has a false front that extends to the peak height and runs the entire width of the building from wall line to wall line. Rafter 14 connects to the south face of this wall. Rafter 1 sits on the top of the south wall joist and is supported by 2x4's at 24"OC. I ran calculations based on the load combinations which will result in the largest expected loading. The existing rafters and ceiling joists are old 2x4's and 2x6's with dimensions of I-5/8" x 3-5/8"and 1-5/8"x 5-5/8",respectively. The load combination is equal to Equation 16-14 in the Oregon Structural Specialty Code which was used to determine the forces on the existing rafters prior to the current modifications. The existing strength properties of the wood were assumed to be Select Structural Douglas Fir-Larch due to the quality of the wood at the time of construction and the small number of knots that are present. The most heavily loaded portion of the roof is that area within three feet of the short end walls. My calculations show that bending loads were just barely over that which are allowed,therefore indicating the need for additional support in this area. Had the contractor continued to install the same supports,shown in Sections B and C, as he did through the central part of the rafter L ors Ciry Hall Roo/Evaluation 8-15-20M Page I oil