950 Corbindale Road – Overcladding

Title: 950 Corbindale Road – Overcladding

Award Category: Exterior Wall

Project Address/Location

950 Corbindale Road

Houston, Texas 77024
United States

Submitted By: Erick Ika

Company Info

Walker Consultants

19710 Gulfwind Drive

Houston, Texas 77094
United States

850-221-0162

[email protected]

Project Description and Background: A four-story office building, which was built circa 1982, was planned to go through renovations encompassing the interior and exterior renovations. The proposed exterior renovations included, but were not limited to, overcladding the building with Exterior Insulation and Finish System (EIFS) cladding, replacing the existing window systems with new thermally broken aluminum window wall systems glazed with insulating glass units, and renovating the landscaping and planter beds at the main entrance. It is our understanding that the design drawings of overcladding would originally be developed by the Architect of Record; however, it was ultimately decided that a building envelope consultant would take this design responsibility. Walker Consultants (Walker) was brought into the project as the building envelope consultant for the specialty contractor, who was responsible to install the EIFS cladding and the new window wall systems. Walker was responsible to develop design drawings that met the Owner’s and project’s specific needs, the Architect of Record’s design intent, and the applicable building codes with local amendments. Time was of the essence since the Owner has required that the design drawings and the exterior renovation be completed within a specific schedule to meet the needs of other interior renovations that were undertaken by some of the building tenants. Accordingly, Walker was required to complete our feasibility study of overcladding and design drawings within the given time constraints. When Walker was brought into the project, no feasibility study had been performed by others for this project to determine if it was feasible to install a new EIFS cladding over the existing brick veneer. Thus, although the Owner wanted to improve the appearance of the building by installing a new EIFS cladding, it was unknown at that early phase of the project whether the proposed overcladding approach could be successfully implemented at this project.

Scope: Since no overcladding feasibility study had been performed for this project, Walker proposed to conduct the following feasibility study as part of Walker’s services: a. General condition of the existing brick veneer: Visual condition assessment of the existing brick veneer was performed by Walker to assess the condition of the brick veneer and develop recommendations of substrate preparations. b. Structural analysis of the back-up wall systems for the existing gravity and/or lateral load-carrying structural elements: The structural analysis was performed by Walker to determine whether the existing structural elements would be structurally adequate to withstand the demand loads of the overcladding project, or if structural modifications/strengthening was required. The back-up wall systems of the building exhibited four (4) types of back-up wall systems, which were concrete back-up wall, concrete masonry unit (CMU) back-up wall, doubly wythe brick wall, and cold-formed metal framing. c. NFPA 285 compliance: Since the subject building exhibited non-combustible exterior wall assemblies/components, introducing a new EIFS cladding, which is a combustible cladding, has triggered the requirements of NFPA 285 compliance. Since no NFPA 285 compliance or test reports are available from the EIFS manufacturer for overcladding, based on Walker’s recommendation, a third-party engineering consulting firm was retained to provide an engineering analysis of the proposed overcladding assemblies for compliance with NFPA 285. Walker took the lead of the NFPA 285 compliance feasibility study, worked closely with the third-party engineering consulting firm, reviewed the engineering report, and provided coordination throughout the project to accomplish this portion of feasibility study. d. Hygrothermal analysis: Based on Walker’s recommendation, a third-party consulting firm was retained to provide the hygrothermal analysis of the proposed overcladding assemblies. Walker took the lead of the feasibility study, worked closely with the third-party consulting firm, reviewed the hygrothermal analysis/report, and provided coordination throughout the project to accomplish this portion of feasibility study. Analysis of the building envelope four control layers was also performed. As part of this study, temperature and humidity gauges were strategically placed in the buildings for a certain period of time to obtain additional data and information that was used to perform the hygrothermal analysis. e. EIFS field bond pull test: The EIFS manufacturer provided the laboratory test report of the EIFS cladding that would be installed at this project. The laboratory test report showed adequate adhesion of the EIFS cladding to the brick veneer to meet the project design wind pressures. EIFS field bond pull tests were performed to verify the actual field conditions. The field tests were performed in general accordance with the EIFS manufacturer’s recommended field test procedures. The results of the field tests also showed adequate adhesion of the new EIFS cladding to the existing brick veneer. Selective demolition or investigative exploratory openings were performed at select locations to view and document the as-built construction of the existing brick veneer, back-up wall systems, and other underlying substrates. Information and data gathered via investigative exploratory openings was used to perform the structural calculations/analysis, NFPA 285 engineering analysis, and hygrothermal analysis.

Solution: The results of the feasibility study confirmed that an overcladding approach can be implemented at this project to meet the Owner’s needs, the design intent of the Architect, and the applicable building codes. This overcladding approach offered the opportunity for the Owner to improve not only the aesthetic of the building, but also the building envelope performance (increased thermal performance by installing new EIFS cladding over the existing brick veneer and new window wall systems, as well as improved air and water penetration resistance performance by introducing a new air and water barrier system for the EIFS cladding). The results of the hygrothermal analysis also confirmed that a vapor permeable, air and water barrier product would be proper to be incorporated into the overcladding system. In addition, the overcladding project was performed while still allowing the building to remain in full operation with very little-to-no disruption to the building normal operations and occupants/tenants, which was especially important to the Owner and the building tenants/occupants. Furthermore, the overcladding approach also eliminated the need to remove the existing brick veneer; thus, reducing the amount of construction and demolition waste, as well the detrimental impacts to the environment. Following the feasibility study, Walker developed the building envelope design drawings for the overcladding and window replacements.

Value: Walker proposed and took the lead of the overcladding feasibility study to ensure a successful exterior renovation project using an overcladding approach can be satisfactorily implemented and accomplished. During the early design phase, Walker also consulted with the local authority having jurisdiction to ensure that the building envelope design would be in compliance with the applicable/adopted building codes with local amendments. The consultation with the local authority having jurisdiction led to a smooth permitting process, and no revision and resubmission was required for the building envelope design drawings. The smooth permitting process certainly helped to meet the project schedule required by the Owner. Walker also performed periodic site observations during the exterior renovation to observe the in-progress overcladding project, as well as to assess whether the in-progress overcladding installation was in general accordance with the design drawings developed by Walker. Walker’s critical contribution to the project has led to Walker being retained directly by the Owner to perform an additional and more comprehensive structural analysis of the back-up wall systems related to the overcladding, as well as being retained directly by the Architect of Record to assist with other building envelope scopes related to the exterior renovation of the subject building. Ultimately, Walker provided our building envelope expertise and services to three separate parties involved in the same project to achieve a common goal, which is a successful project.

Project Images

Additional Info: Owner Company: 950 Corbindale, LP/The Allison Company Contact Name: Les Allison, Clay Allison, and Richard Plessala Address: 3201 Kirby Drive, Suite 500, Houston, TX 77098 General Contractor Company: Linbeck Group Contact Name: Allston Marble Address: 3900 Essex Lane, Suite 1200, Houston, TX 77027 Specialty Contractor Company: Southern Wall Systems Contact Name: Ryan Rackliffe Address: 504 Spring Hill Drive, Suite 350, Spring, TX 77386 (Texas Office)

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