Balcony and Parapet Wall Repairs Groves of Palatine Condominium Buildings

Title: Balcony and Parapet Wall Repairs Groves of Palatine Condominium Buildings

Award Category: Exterior Wall

Project Address/Location

390, 410, 440, and 470 West Mahogany Court

Palatine, Illinois 60067
United States

Submitted By: Charles Sietmann

Company Info

Building Technology Consultants, Inc.

1845 East Rand Road
Suite L-100
Arlington Heights, IL 60004
United States

(847) 970-8023

[email protected]

Project Description and Background: The Groves of Palatine Condominiums include four 7-story buildings constructed between 2002 and 2005. The floors of each building consist of hollow core precast concrete planks supported on steel framing and concrete masonry walls. The exterior walls of the building are primarily clad in brick and stone masonry. The exterior walls at the first floor of each building consist of exposed concrete. Each building includes 56 balconies and 2 rooftop terraces at each end. The 2nd floor balconies are located over occupied storage space and include a waterproofing membrane and pavers. The balconies at floors 3 through 7 are uncoated, solid, precast concrete slabs supported by masonry walls and piers. The rooftop terraces are enclosed by brick masonry parapet walls with cast stone accents and metal coping caps. During exterior facade evaluations performed by BTC, deficiencies in the balcony columns and parapet walls were observed that presented significant structural integrity concerns. BTC completed a repair alternative study to evaluate various repair options to address these deficiencies. Based on that study, the Association authorized BTC to proceed with developing repair documents and bidding the work considering the following selected repair alternatives: 1. Repairing balcony column structural deficiencies by installing auxiliary external steel support columns. 2. Repairing parapet wall deficiencies by rebuilding the walls in their entirety. 3. Repairing deficiencies associated with the second floor limestone coping caps by performing comprehensive repairs without providing railing post anchorage, since the railings have been made structurally sound.

Scope: Our scope consisted of several investigations, include evaluation of the exterior walls, parapet walls, and balconies. BTC performed an up-close visual review of the exterior walls from a manlift, peformed hammer sounding of masonry with a rubber mallet at representative locations to evaluate loose or delaminated masonry, and made numerous exploratory openings with the assistance of a contractor. Our investigation of the parapet walls consisted of an R-meter survey over the interior brick masonry surfaces, exploratory openings, and calculations to evaluate the as-built capacity of the parapet walls. Some of the observed deficiencies present significant structural integrity concerns, including the following: 1. Lack of adequate support of balcony slabs on masonry support piers. 2. Lack of adequate attachment of balcony slabs to masonry support piers. 3. Lack of reinforcement within balcony support piers. 4. Lack of adequate expansion joints to accommodate differential movement, resulting in outward displacement of masonry and potential fall hazards. Also, due to the apparent lack of vertical reinforcing steel in the parapet walls, resistance of the parapet wall to overturning is primarily provided only by the weight of the wall itself. However, our calculations indicate that under the code-prescribed wind load at the time the wall was designed and constructed, it is at least 68% overloaded without vertical reinforcing steel (i.e., the wall could simply overturn if subjected to the code-prescribed wind load). Under the current code-prescribed wind load, it is at least 87% overloaded. Based on our findings, it was our opinion that the parapet walls should be rebuilt to provide adequate resistance to wind loads, proper drainage, and proper and adequate anchorage of the exterior brick masonry wythes. BTC was retained in 2019 to design improvements to these components. The design included supplemental balcony support columns at all balconies and support brackets within the storage spaces, along with the rebuilding of the terrace parapet walls, and waterproofing repairs and through-wall flashing replacement at the 2nd floor balconies.

Solution: BTC presented several options to address all observed deficiencies. These options include a complete re-cladding of the masonry walls, demolition and rebuilding of the balconies, or a combination of localized repairs and reconstruction of certain components. With budget a major factor, a combination of repairs were implemented. Rather than performing a complete re-clad and removal of the balconies, the parapet walls were rebuilt and supplement reinforcing was provided at the balconies. Auxiliary external steel support columns were designed to properly support each balcony down to the existing foundation walls.

Value: Developing cost-effective and innovative solutions to address the balcony issues provided tremendous value to the Association. Complete removal of the balconies would have added substantial costs to the project, and would have been extremely disruptive to the unit owners. Existing balconies were able to remain in place with minimal impact to residents. Although complete removal and rebuilding of the parapet walls was necessary at each building, a complete re-clad of the building was avoided and more cost-effective localized repairs were implemented. BTC was able to provide value from the design phase through the construction phase. BTC was able to ensure the repair work was performed in accordance with the design.

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