RE: Pacific Shores VIS Block Second Floor Walkway Structural Review

Transcription

1 April 20, 2017 The Kerr Group Management Corp. Terry Kerr, Owner / Manager terry@thekerrgroup.ca Phone: RE: Pacific Shores VIS Block Second Floor Walkway Structural Review Dear Terry, On April 12, 2017, Zelwood Construction & Restorations (ZCR) reviewed the causes of the ongoing water ingress noted at the soffit of the second floor exterior walkway of the 700 Block, generally about the parkade side and the fountain side of the building. To complete our review of these areas, we removed sections of the cedar channel soffit boards and underlying gypsum wallboard (soffit boards were replaced at the end of review but in as-is condition). We determined that the cause of the water ingress is due to failure of the existing second floor membrane along the exterior perimeter of the walkway sections and possibly along any laps in the coverage area. See photos below for all reviewed areas. At the parkade side location, the resultant water damage due to the membrane failure has caused extensive wood rot to the sub-floor sheathing, wood column, four ply built-up beam end, and exterior joists. During our review, it was observed that there is another point of water ingress at the edge of walkway at the exterior face of the stairwell. The extent of moisture damage appears to run between the stairwell to the face of the second floor units at this end of the walkway. The wood rot towards the interior affects mostly the sub-floor sheathing and the supporting four ply built-up beam. The extent of

2 wood rot at the column to beam area has caused sagging of the beam and crushing of the column and sheathing. These members need to be replaced as their capacity to carry their intended loads has been severely compromised. The sheathing cannot be replaced by any other means than by removing topping and membrane. As of the date of this report, April 20, 2017, a temporary post has been installed at the critical point of sag in this beam. This has been installed as a safety measure and will be removed once the structural members have been replaced. The fountain side area of water ingress is similarly due to a failure in the membrane of the walkway and additional water ingress was noted around the base of the column located at the inside corner of the retaining wall at the top of the fountain. Wood rot of the sheathing and joists has occurred as well as framing members comprising the drop down ceiling. It was observed that the original beam in this location has been replaced with a pressure-treated built-up beam; this appears to be in serviceable condition. Attempts to mitigate the water ingress at this location by installation of additional flashing and sealants along the edges of the walkway and bases of columns have not been successful as the sealant depends upon the concrete topping of the walkway which is neither waterproof nor unbroken along the exterior edge. To replace the wood rotted sub-floor sheathing of both areas and replace the failed membrane, it will be necessary to remove the concrete topping around those areas; approximately 200 sq.ft and 300 sq.ft respectively. The following Scope of Work will be required to replace all wood rotted areas and install new concrete topping to match existing adjacent areas. We propose that a new two-step flashing be installed, where the first drip flashing has a deep vertical face that will support the membrane to be adhered over the top and down two inches on the vertical. The second flashing will overlay the membrane and protect it from UV degradation and weathering. The concrete topping will be finished over these. If access to this area of 700 Block will be required during remediation, then additional temporary shoring and covered passageways will be required to protect the public. Parkade Side Scope of Work: 1. Install temporary shoring walls (both sides of affected beam to carry joists) 2. Demolition ( soffit, concrete topping, membrane, sheathing, 4 ply beam, column, and affected joists) 3. RE/RE existing second floor guardrail (if required) Page 2

3 4. Install new beam, joists, sheathing and column (column will be provided proper base that will lift it off of concrete retaining wall but also anchor it down). 5. Install new membrane, flashing and sealants (new membrane will be fully adhered and second loose lay ply will be installed to protect base layer). 6. Install stamped concrete topping to match existing (colour match will be done as best as can be but weather staining and pedestrian traffic wear of existing adjacent area cannot be duplicated). Fountain Side Scope of Work: 1. Install temporary shoring wall (inside of beam to carry joists) 2. Demolition ( soffit, concrete topping, membrane, sheathing, drop down ceiling framing members and affected joists) 3. RE/RE existing second floor guardrail (if required) 4. Install new joists, sheathing and drop down framing members. 5. Install new membrane, flashing and sealants (new membrane will be fully adhered and second loose lay ply will be installed to protect base layer). 6. Install stamped concrete topping to match existing (colour match will be done as best as can be but weather staining and pedestrian traffic wear of existing adjacent area cannot be duplicated). For budgetary purposes, the strata should expect the above noted scope to cost in the order of $20,000 in labour, $15,000 in topping, membrane, and flashings, and $5,000 in materials and finishing for a total of $40,000. The anticipated work schedule would be 3 weeks. Please contact the undersigned for any questions. Regards, Donovan Campbell, P.Eng. Zelwood Construction Restorations Project Engineer / Project Manager Page 3

4 Parkade Side: wood rot at top of column, soffit framing; mould and saturation at drywall Parkade Side: Wood rot, mould and saturation of four ply built-up beam Page 4

5 Parkade Side: Water ingress and wood rot at stairwell end outside face Parkade Side: Moisture accumulation and staining at second floor column base Page 5

6 Parkade Side: Exterior face of stairwell at area of wood rotted structural members Parkade Side: Wood rotted and crushed sheathing at column area Page 6

7 Fountain Side: Saturated and mould covered gypsum wallboard Fountain Side: Saturated and rotted sheathing, joists, and drop down framing Page 7

8 Fountain Side: Wood rot at sheathing, joists and drop down framing along outside edge of walkway Fountain Side: Water ingress and wood rot at inside corner of fountain retaining wall Page 8

9 Fountain Side: Moisture stains down retaining wall through second floor walkway Fountain Side: Moisture staining and likely path of water through walkway to below Page 9

10 Fountain Side: Edge of walkway sealant is failed and ineffective Page 10