Planning Rationale
Envelope Renovation - Overview
The scope of envelope renovations varies from localized repairs to full building envelope repairs. The extent of the work shall be determined based on the severity of the defects identified in the transferred scope of work and verified by the AOR on site. Typical defects include, but are not limited to, damaged masonry, deteriorated window heads, deteriorated/failed sealant and deteriorated roofing elements. Left unchecked, exterior envelope defects can lead to significant structural and architectural issues and shall be addressed to ensure the integrity of the building structure and related interior finishes.
Key Considerations
- Apply a consistent approach to the performance of the envelope.
- Identify causes of defects and areas in need of attention/restoration. Ensure that the overall condition of the building is assessed. There are often multiple problems contributing to deteriorating conditions. The AOR shall perform a complete visual inspection in support of a holistic approach to the design.
- Causes of damage: Water infiltration at the roof, lack of roof or window/wall maintenance and lack of masonry control and expansion joints are frequent causes of damage at the exterior envelope.
- Interior conditions: It is important to note that problems at the interior of the building are often symptoms of issues at the exterior envelope.
Structure Types
Envelope renovation scopes are based on the existing envelope type and structure. There are many variations of envelope construction and the building enclosure can generally be classified based on the vintage of construction.
- 1880 - 1900: Mass masonry with wood framing. Typically buildings of this vintage have wood and stone lintels. Detailing at the facade generally includes stone and terra cotta elements.
- 1900 - 1920: Mass Masonry with steel framing, including steel lintels. Typical facade detailing includes stone and terra cotta elements.
- 1920 - 1940: Steel frame construction and early reinforced concrete construction with mass masonry walls. Buildings of this vintage generally have steel lintels and stone or terracotta facade detailing.
- 1940 - 1980: Steel and reinforced concrete frame construction. Buildings of this vintage include envelopes with early cavity wall and brick veneer systems.
- 1980 - 2000: Modern steel and concrete frame construction. Envelopes typically consist of modern cavity walls and curtain wall systems.
- 2000 - Present: The envelope construction is generally similar to the previous era, but also includes modern flashings, waterproofing and insulation.
Materials
Materials used on envelope renovations shall conform to the standards outlined in the CPS specifications. Masonry repair materials at the exterior facade of the building shall generally match the existing architectural configuration and be sympathetic to the aesthetic of the building.
Energy Design
The AOR shall review the code requirements for the building envelope, design repairs and systems replacements accordingly. The design shall also comply with the CPS standards for energy requirements at the exterior envelope.