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BLD18-1634 - Bell Street - (Rvw-1, dbeck, 3-3-2019).doc March 3, 2019 Leif Bjorback Building Official City of Edmonds 121 5th Avenue North Edmonds, WA 98020-3145 Subject: Bell Street Townhouses Permit: BLD18-1684 Per your request, Beck & Associates has completed structural and non-structural reviews of the drawings and calculations for conformance with the 2015 International Building Code (IBC), as adopted and amended by the State of Washington (WSA) and the City of Edmonds (ECC). Our review of the plans and calculations indicates that corrections are necessary prior to permit issuance. The applicant should address the following comments in itemized letter format in addition to making corrections & revisions to the drawings. Corrections and revisions to the drawings should be clouded so that they are clearly identifiable. Applicable Codes The architectural plans show a mix of references from both the IBC and the IRC. Before we are able to provide a more thorough review of the plans, the architect is required to decide the code path that he wishes/is permitted to take. The drawings will then need to be updated to be consistent with and correctly referencing the chosen code and code sections for applicable provisions. While the requirements of the IRC and the IBC are similar, they are not identical. Currently, the Building Code Data on A001 references the IRC. However, the IBC is utilized for determination of allowable heights, areas, etc. A single code path is required to be chosen and followed throughout the plans. The IRC is applicable to townhouses (R-3) that are not more than three stories above grade plane. R101.2 The IBC limits the height of V-B construction (with a NFPA13R sprinkler system) for R-2 occupancies to three stories. However, two of the townhouses are currently shown to be 4 stories in height. IBC Ch. 5 The architect will need to demonstrate that the townhouses/building are/is by code definition only 3 stories in height (reference definitions for grade plane, story above grade plane, and basement in either the IRC or IBC). Provide diagrams and complete calculations on the plans to demonstrate that the lowest level can be considered a basement by IRC/IBC standards. Please be aware that it is more likely that the building as a whole can be shown to be on 3 stories and that the lowest level is by definition a basement (IBC) rather than showing that the individual townhouses are all 3 stories or less. R101.2 Alternatively, the building will need to be constructed under the IBC of a higher Construction Type that has an allowable number of stories for an R-2 occupancy that is 4 stories or greater. IBC Ch. 5 If the building is constructed under the IBC, the plans will need to demonstrate that exterior walls within 10’-0” of the property line are 1-hour rated (assuming Type V-B Construction). The Site Plan (A001) currently shows the exterior walls on the east side of the building to be 9’-8” from the property line. Provide coordination. IBC Table 602 Building Envelope Pursuant to RCW 64.55, all applications for construction of multi-unit residential buildings must include building enclosure design documents that identify the building enclosure, including but not limited to, waterproofing, weather proofing and/or otherwise protected from water or moisture intrusion. The building enclosure documents must contain a stamped statement by the person stamping the building enclosure design documents stating, in substantially the following form: “The undersigned has provided building enclosure documents that in my professional judgment are appropriate to satisfy the requirements of RCW 64.55.005 through 64.55.090." Additionally, all multi-unit residential buildings are required to have the building enclosure inspected by a qualified building enclosure inspector during the course of construction. This inspection is to be completed by a third party, independent inspector. The City may not issue a Certificate of Occupancy until the qualified, third party independent inspector prepares a report and submits to the building department a signed letter certifying that the building enclosure has been inspected during the course of construction and that the construction is in substantial compliance with the building enclosure design documents. The requirement for third party inspection needs to be specified on the plans. Alternatively, a recorded “sale prohibition covenant” is required to be submitted for review. A “sale prohibition covenant” is a recorded covenant that prohibits the sale or other disposition of individual dwelling units as or as part of a condominium for five years or more from the date of first occupancy except as otherwise provided in section 10 of the act, a certified copy of which the developer shall submit to the appropriate building department; provided such covenant shall not apply to sales or dispositions listed in RCW 64.34.400(2). The covenant must be recorded in the county in which the building is located and must be in substantially the following form: This covenant has been recorded in the real property records of Snohomish County, Washington, in satisfaction of the requirements of sections 2 through 10 of this act. The undersigned is the owner of the property described on Exhibit A (the "Property"). Until termination of this covenant, no dwelling unit in or on the Property may be sold as a condominium unit except for sales listed in RCW 64.34.400(2). This covenant terminates on the earlier of either: (a) Compliance with the requirements of section 10 of this act, as certified by the owner of the Property in a recorded supplement hereto; or (b) the fifth anniversary of the date of first occupancy of a dwelling unit as certified by the Owner in a recorded supplement hereto. Energy (2015 WSEC, Residential) The following requirements of the 2015 WSEC need to be specified on the plans: A permanent certificate is required to be completed and posted on a wall in the space where the furnace is located (or other approved location) and list the following information: R-values, U-values, Results from duct system air leakage testing, Results from building envelope air leakage testing (blower door test), Types and efficiencies of heating, cooling, and service water heating equipment. R401.3 New exterior headers are required to be insulated with a minimum of R-10 insulation. Provide detailing. Table R402.1.1, footnote k Corners of stud walls are required to be fully insulated. 202, definition of ‘Intermediate Framed Walls’. Provide detailing. Ducts are required to be insulated to a minimum of R-8. R403.3.1. Mechanical system piping is required to be insulated to a minimum of R-6. R403.4. Hot water pipes are required to be insulated to a minimum of R-3. R403.5.3 The dwellings are each required to be tested and verified as having an air leakage rate not exceeding 5 air changes per hour (unless a more stringent requirement is mandated in order to achieve the additional required credits. R402.4.1.2 Mechanical ducts are required to be seal tested in accordance with 403.3.2. Testing to comply with WSU RS-33. A minimum of 75% of all permanently installed lighting is required to be high-efficacy. 404.1 The plans currently indicate that 2.5 additional energy credits are required for medium dwelling units. The 2015 WSEC requires 3.5 credits. R406 Update the design accordingly. The plans indicate that Option 2a Air Leakage Control and Efficient Ventilation is chosen for credits. Update the plans to identify the requirements under this option. The plans indicate that Option 5a Efficient Water Heating is chosen for credits. Update the plans to specify the requirements for these credits: gas, propane or oil water heater with a minimum EF of 0.74. General Each sleeping room is required to be provided with at least one exterior emergency escape and rescue opening. Identify the location of each egress window on the plans and verify that the required clear opening dimensions will be provided. R310.2.1; IBC 1030 Basements are required to be provided with an emergency escape and rescue opening. An overhead garage door does not meet the requirement for the opening. Update the plans accordingly. R310.2.1; IBC 1030 Identify all locations on the plans where safety glazing is required (doors and windows). R308.4.5, IBC 2406.4.5 The plans will need to be updated to demonstrate that requirements for unvented roofs will be met. R806.5; IBC 1203.3 Where fire-resistant-rated assemblies are required, provide complete specifications and detailing for construction. We recommend that an exact copy of the listed, tested assembly be included within the drawing set to insure proper construction and inspection. Detailing of fire-resistant-rated assemblies needs to demonstrate that required fire-resistant-rated assemblies are maintained at transitions such as at floors, the roof, etc. Identify all locations on the plans where exhaust fans are required to be provided. Identify the capacity of each exhaust fan. IRC Ch. 15 Identify the location of all appliances (furnace/heaters, hot water heater, etc.) on the plans. Update the plans to demonstrate how accessibility requirements for dwelling units will be met. Please be aware that multi-story units provided with elevator service are required to be provided with accessible dwellings (IBC 1107.7.2). R320; IBC 1107 Drawing Sheets A003 – Roof Plans, Details Reference 23/A003. 5/8” type X GWB is specified each side of both trusses. Provide additional specifications on the detail to clarify what is intended. It doesn’t appear that the required 1-hour separation is maintained with (2) layers of ½” type X gwb. A complete 1-hour assembly is required to be maintained. A501 – Details Reference 12/A501. Slab insulation is required to extend downward form the top of the slab. Update the detail accordingly to provide a complete energy envelope. WSEC R402.2.9 Geotechnical General PanGEO is required to conduct a review of the project plans and specifications. PanGEO should prepare a letter summarizing the review and providing any additional recommendations. Where additional recommendations or corrections are provided, those recommendations and corrections are required to be addressed within the drawing set when submitting in response to the Beck & Associates review letter. (p. 14, geotechnical report) Structural General The “structural calculations” package submitted with the drawings are not calculations at all but a replica of what is shown on the structural plans. Provide complete gravity calculations to substantiate the gravity design. Provide complete lateral calculations (both wind & seismic) to substantiate the lateral design. Provide calculations to substantiate the design of retaining walls. Design must be consistent with the recommendations of the geotechnical engineer, PanGEO. S1 – General Notes & Framing Plans Reference note #6 of the Shear Wall Schedule. The plate washers are required to extend to within ½” of the edge of the bottom plate on the side(s) of the sheathing. This needs to be specified. SDPWS 4.3.6.4.3 Reference the Foundation Plan. Numerous straps are provided on the longitudinal shear walls. However, no holdowns are provided along the longitudinal walls at the foundation level. All overturning forces are required to be carried down from above. We anticipate that holdowns will be required to be provided at each end of each of the shear walls along the longitudinal sides at the foundation level. Provide calculations for sizing of the holdowns. Specify required slab on grade thickness and reinforcement. Reference the 2nd Floor Framing Plan. Specify the required shear wall type along grid A. Reference the shear walls along grid B. One of the shear walls is not identified (P1-2). Update the plans accordingly. S2 – Framing Plans Reference the 3rd Floor Framing Plan. It appears that PSL beams are required at the elevator openings to support the joists. Specify required beams at the elevators between grids B & B.1 (2 locations) and between grids C.1 & D. Reference the 4th Floor Framing Plan. It is apparent that beams are required (2 locations) along grid B.2 in order to support framing. These beams need to be specified (3-1/2x11-7/8 PSL beams?). It appears that a PSL beam is required at the elevator openings to support the joists. Specify required beam at the elevator between grids C.1 & D. An MSTC66B3 is specified at the header along grid 1 approximately at grid A.5. A similar situation occurs on along grid 3 approximately at grid A.5. The MSTC66B3 needs to be specified at this location as well. The following comments also apply to the condition along grid 3 (in addition to the condition along grid 1). The header is required to be designed for loads considering overstrength (=2.5). Provide an analysis and design for the header accordingly. ASCE 7-10 12.3.3.3 The overturning forces on the header will produce uplift forces at each end of the header. Provide an analysis for the uplift force at each end of the header. Design is required to consider overstrength since the header supports the discontinuous shear wall. Provide design for header supports (bundled studs), considering overstrength. Provide a complete load path for the uplift forces (considering overstrength), until they are fully resisted. The GL 5-1/2x15 beams along grid E support shear walls from above. Since the shear walls are discontinuous, the beams, beam supports, and uplift at the end of the beams are required to be designed considering overstrength. Provide an analysis and design accordingly. ASCE 7-10 12.3.3.3 The 5-1/4x11-7/8 PSL beams along grid D.8 support a shear wall from above. It appears that holdowns should be provided at each end of the supported shear wall to the beams below. Provide an analysis and design (holdowns) that is consistent with that analysis. Since the shear wall is discontinuous, the beams, beam supports, and uplift at the end of the beams are required to be designed considering overstrength. Provide an analysis and design accordingly. ASCE 7-10 12.3.3.3 S4 - Details Reference Section #13. Specify the required footing width (18” minimum per the geotechnical engineer). S5 – Details Reference Sections #17 & #18. Horizontal reinforcement is required to be provided with 180 degree hooks at each end. Update the details accordingly. ACI 318-14 Reference Section #23. The end of the joist needs to be separated from the concrete wall in order to prevent deterioration of the joist. Specify the required material to provide this separation. S6 – Details Reference Sections #26, #27, and #28. Plate nailing of 16d@6” o.c. is not adequate in all cases to transfer shear wall forces to framing below. Perhaps spacing of the 16d nails should be specified to match Shear Wall edge nailing per the Shear Wall Schedule. This would insure adequate load transfer is provided from the shear wall above. Reference Section #28. The floor sheathing is required to continue through the double wall. The buildings are not designed with a seismic separation and are therefore required to be integrally connected. Update the detail accordingly. Reference Section #32. Specify a connection from the LSL rim board to the double top plate of the shear wall below in order to fully transfer shear forces (A35@16” o.c.?). Toenails are only permitted to transfer shear forces where the loads are 150 plf or less. In this case, the loads are higher than 150 plf. Therefore, toenails are not considered to contribute to shear transfer and another mechanism is required to transfer the entire shear force. Update the detail accordingly. SDPWS 4.1.7 S7 – Details Reference Sections #33 & #34. Plate nailing of 16d@6” o.c. is not adequate in all cases to transfer shear wall forces to framing below. Perhaps spacing of the 16d nails should be specified to match Shear Wall edge nailing per the Shear Wall Schedule. This would insure adequate load transfer is provided from the shear wall above. Reference Sections #34, #36, #37, and #38. Specify a connection from the LSL blocking or rim board to the double top plate of the shear wall below in order to fully transfer shear forces (A35@16” o.c.?). Toenails are only permitted to transfer shear forces where the loads are 150 plf or less. In this case, the loads are higher than 150 plf. Therefore, toenails are not considered to contribute to shear transfer and another mechanism is required to transfer the entire shear force. Update the detail accordingly. SDPWS 4.1.7 Reference Section #35. The floor sheathing is required to continue through the double wall. The buildings are not designed with a seismic separation and are therefore required to be integrally connected. Update the detail accordingly. Reference Section #40. Specify load for which the truss blocking (in the plane of the truss blocking) is required to be designed in order to transfer lateral forces from the roof diaphragm to the shear wall below. Please contact me should you have any questions. Respectfully, Douglas Beck, PE, SE Beck & Associates, PLLC BLD18-1684 (Structural & Non-Structural Reviews) March 3, 2019 Page 6 of 7 16425 SE 66th Street, Bellevue, WA 98006 ● beckpllc@msn.com ● PH: 206-313-3739 Beck & Associates, PLLC Structural Engineering & Code Consulting 16425 SE 66th Street, Bellevue, WA 98006 ● beckpllc@msn.com ● PH: 206-313-3739