Planning Rationale
Chicago Public School buildings are constructed using proven structural systems and materials, which are highly durable and time-tested. Material choices and systems represent the result of an extensive vetting process and address key goals for minimizing maintenance and maximizing high performance. These systems are proven to create a resilient, energy efficient, sustainable building, providing an environment for students that is, above all else, “safe, warm, and dry.”
Goals and Properties of Exterior Wall Systems
Goals for the exterior wall system:
- High performing, resilient buildings requiring minimal maintenance
- Provide robust, durable, and cost effective system
- Acoustically separate from exterior sound sources
- Eliminate air and moisture infiltration
- Minimize thermal transmission
- Provide resilient system
- Exterior wall assemblies to meet the code required ratings for the particular site
- Wall assemblies other than masonry, must have a UL-tested rating of at least one-hour, provide a UL-tested rating of two-hours if the project requires
- Building envelope commissioning to be performed for the buildings
Standard properties of the exterior wall system:
- Masonry Facades: CPS standard materials to include Standard Modular Brick and Utility Brick with Cut Limestone or Cast Stone components. These stone components are to be used as accents only due to cost constraints. Consider texture and color for variation of brick. Properly ventilated glazed materials may be considered with CPS approval.
- Fenestration: Punched openings with architectural windows shall be utilized. Not approved for use include: curtainwalls, spandrel glass or “shadow box” assemblies, or coated or colored glass
- Continuous Air and Vapor Barrier: Shall be provided
- Thermal Bridging: Shall be minimized
- Copings: Limestone or pre-engineered, factory fabricated, pre-finished aluminum systems
- Management of Condensation and Moisture Infiltration:
- Dew point has to be outside stud cavity
- Insulation to be outboard of air and vapor barrier. No insulation allowed within the stud cavity
- Sealed penetrations
- Unconditioned soffits or overhangs require balanced ventilation provisions at the perimeter edge(s)
Exterior facade materials that are not permitted:
- Unglazed white brick
- Pre-cast concrete
- Brick veneer panels
- Composite metal panels
- Fiber cement panels