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REVIEWED BLD2024-0917+Calculations+7.5.2024_2.44.47_PM+4360181 (2)SIDES WAY ENGINEERING 20305 87" Avenue W. Edmonds, WA 98026 (425)673-4160 November 20, 2023 Parkview Twin Condominiums HOA 517 & 519 41h Avenue S. Edmonds, WA 98020 RECEIVED BLD2024-0918- UNIT D Jul 16 2024 BLD2024-0917- UNIT B CITY OF EDMONDS................................................ DEVELOPMENT SERVICES DEPARTMENT REVIEWED BY CITY OF EDMONDS BUILDING DEPARTMENT ............................................... Subject: Structural Observation of Exterior Deck Dry Rot Location: 517 & 519 4th Avenue S., Edmonds, WA 98020 To Whom it May Concern, Sidesway Engineering has completed our assessment of the twin condominium buildings noted above. We performed a site visit on September 18th and observed each of the eight cantilevered deck systems from the exterior of the building. The purpose of our observation was to assess the dry rot and determine whether or not water intrusion had affected other areas of the structure beyond the west decks. Field Observations: 517 Unit A: • The rim board had been repaired previously but a continuous member was not installed. • There was 20" of significant dry rot observed on the west end of the north deck beam. • The edge of deck flashing protrudes above the topping slab allowing water to run below the slab and into the wood framing. • The handrail was not vertical which caused gaps in the rubber gaskets sealing the connection point. 517 Unit B: • The northern 12" of the rim board, and west 12" of the north deck beam had significant dry rot as well as a 24" x 24" portion of the deck sheathing at the northwest corner. • The tile deck surface had cracked and moss was observed along the perimeter. • The handrail was not vertical which caused gaps in the rubber gaskets sealing the connection points. 517 Unit C: The outermost (2) deck joists had crushed approximately 1/8". There was 1/2" of dry rot extending along the northern 48" of the west joist. The northern beam had significant twist, however no rot. The rim board had been repaired previously but a continuous member was not installed. 517 Unit D: • The beams for this unit were wrapped with cedar fascia board. The cedar had dry rot at the west end which extended approximately 2" into the concealed wood beam beyond. • The first two deck joists have crushed 1/8" - 3/8" into the beam. The dry rot extended approximately 18" down the bottom of the first joist. • The rim board had been repaired previously but a continuous member was not installed. • A strip of sheathing on the outer joist bay had dry rot. 519 Unit A: • The west 36" of the north deck beam had significant dry rot along the top 3" of the beam. The beam has warped approximately 1" out of plumb. • The first deck joist had crushed approximately 1/2" into the beam. • The west 16" of the south deck beam had significant dry rot along the top 4" of the beam. • The edge of deck flashing protrudes above the topping slab allowing water to run below the slab and into the wood framing. • The deck topping slab has cracked in several locations allowing water penetration down to the wood framing. 519 Unit B: 0 This deck was generally found to be in good condition. Parkview Twin Condominiums November 20, 2023 Project No. 23088.01 519 Unit C: The edge beams have been repaired with a splayed scarf joint at approximately mid -span of the cantilever. The joint has (3) 1/2" through bolts as well as an adhesive along the 301 sloped joint. More information on the adhesive will be required to evaluate this connection which is potentially affected by two different wood species, moisture, and the type of pressure treatment used in the new portion. This is an unconventional beam upgrade. There was approximately 1" of dry rot along the first joist in from the rim. The northwest corner of sheathing had dry rot. 519 Unit D: • The rim board had been repaired previously but a continuous member was not installed. • The first joist and rim were repaired with a smaller sized joist. • The second deck joist had crushed approximately 1/2" into the beam. • The west 30" of the south deck beam had significant dry rot along the top 3 1/2" of the beam. • The southwest corner of sheathing had dry rot. Conclusions/Recommendations: The decks were generally found to be in similar condition with observed dry rot on the western edge of each of the decks except 519 Unit B. The source of the water causing damage is generally a result of the failed topping slab, failed edge flashing, or improperly installed leaking handrail connection points. Several units have been repaired previously, perhaps as part of the handrail installation, however non -continuous members were installed which do not meet code and likely cause handrail movement compromising the connection point seal. Analysis was performed on the deck joist and beam framing to see how much material loss could be tolerated before upgrades are required. For the joists, we determined that 1/2" depth of material loss would still meet current code requirements for the applied loads. For the beams however, we determined that the existing beams do not meet current code requirements with a tile overlay. With the tile removed, the 4x12 beams were found to be at 100% capacity with no material loss. The 4x10s were shown to be inadequate with the tile and without the tile, deflecting far beyond code allowances. The original building drawings were reviewed as part of our evaluation. These drawings do not detail or call for a topping slab on the exterior decks. They simply note for a fiberglass cover over pressure treated plywood, neither of which we observed. This could explain the overstresses found in the 4x10 beams. The topping slab on each deck should be removed to mitigate future water intrusion either through the slab itself, observed cracks in the slabs, or travel below the detached flashing around the perimeter. Additional code analysis will be required by an architect to determine the viability for this solution due to potential issues with the fire code and additional step height that would result. Potentially the existing sheathing, once repaired, could be overlayed with pressure treated plywood for additional moisture protection and to make up a portion of the removed deck height. Then we'd recommend a solid one-piece poly -vinyl or similar deck surface that extends below the siding and wraps over and down the perimeter of the deck framing. The non -pressure treated beams will require some level of upgrade, then should be wrapped for additional protection. Our conclusions and recommendations are the professional opinion of Sidesway Engineering based on the observations at the time of our assessment. Our services were performed subject to the standard of care applicable to professional services and doesn't warrant or guarantee that all conditions were discovered at the time of our site visit. Please contact us if any additional structural defects are discovered or if there are any questions or concerns related to observations and recommendations above. Sincerely, Chris Bernards, PE, SE, LEED AP Principal 20305 87" Avenue W. Edmonds, WA 98026 SI DE 5WAY (425) 673-4160