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  1. Design and Construction /
  2. Vol. 4 Renovations /
  3. 2.0 Project Types and Typical Scope Elements /
  4. 2.2 Exterior

2.2.4 Windows

Planning Rationale

Window projects can occur as an independent project or as part of a larger exterior renovation. Depending on the existing conditions, windows may be replaced or retrofitted/repaired.

For all new and renovated Window Construction, refer to the New Construction Guidelines: Volume 3, Chapter 2.1.4 Windows.

Typical Considerations for Window Renovation shall include, but are not be limited to the following:

Window Replacement

Ideally window replacement projects are concurrent with or follow exterior facade repair projects so that lintels and other structural concerns are addressed. The primary goals of window projects are:

  • To replace windows that are over 20 years old, that are non-functioning, have poor acoustic or insulating value, and that are comprised of acrylic/polycarbinate/Lexan.
  • New windows shall be new AW grade aluminum windows, and shall be sympathetic to the original building design. When buildings are landmarked red or orange listed, the design shall be coordinated with the City of Chicago Department of Planning and Development Historic Preservation Division.
  • Steel framed windows meeting fire rating shall be installed where required by code.

Window Retrofitting/Repair

Windows may be retrofitted/repaired when windows have been observed to be in good overall condition. Retrofitting/Repairs include replacing missing or damaged stops and non-functioning balances; scraping and painting; re-glazing, and installing new backer rod and sealant. Specialty window consultants may be utilized to provide detailed repair scope of work for more accurate estimation purposes.

  • Existing building conditions for windows above the standard reach range will require remote operators sized to satisfy reach range and operating force requirements.
  • A landmarked facility with existing double or single hung window types that are not being replaced, may require retrofitted remote operators sized to meet the required operating force.

Historical Restoration

For older buildings with historic significance that may have previously received a window replacement project, the goal is to restore sympathetically to the original design by selecting windows which simulate or reference the look of the original design. For this purpose, original photos and drawings shall be reviewed.

Landmark, Orange Status & Similar Designations: When determining the building’s historic appearance, consider the profile of the entire window assembly including muntins, mullions, window sills, fascia, soffits and cornices.

Window Type

Approved window types consists of the following:

  • Replacement Fixed, Non-Operable Windows
  • Replacement Outswinging Awning Windows
  • Existing Double Hung Windows
  • Existing Spandrel Windows
  • Existing Fire Rated Windows
  • Existing Curtain Wall, Windows (Typically not per CPS standard)

Fixed, Non-Operable Windows

Where required, fixed, non-operable windows shall be replaced to meet new standards of a minimum of two (2) ADA compliant operable windows per classroom.

Outswinging Awning Windows

Landmarked facilities with existing double or single hung window units that do not meet the required operating force are required to be replaced with a manufacturer’s standard awning window simulated to appear as a double hung window. The accessible operating hardware for a double or single hung window is ineffective and difficult to achieve. The window manufacturer’s approved accessible awning window hardware must perform within the required range of operation.

Spandrel Windows

The intent is to replace the existing windows with those sized to the original rough openings and to match the historic original appearance and method of operation. In older buildings, spandrel metal or glass is occasionally found installed in historic buildings, where it has been used to reduce the overall height of the window opening. In the past, this was done to hide dropped ceilings installed below the height of original plaster ceilings. Create gypsum board soffits to transition between the window head and the lower ceiling height where needed.

  • Window Section: In the case of tall openings where windows have been divided in three sections and the top section has previously been infilled with an opaque panel, refer to criteria for new window replacements, as follows:
    • Top fixed section shall be replaced with glass if that was the original historic configuration.
    • Heights to be coordinated with existing unit ventilators, or shelving.
  • Window Panes: All new windows are to confirm with CPS specifications, typically requiring 2 panes of glass unless special acoustical requirements need to be met. Ensure that no operable window section weighs more than 100 pounds.

Fire Rated Windows

Fire rated windows are required in locations such as: adjacency to fire escapes, over low roof assemblies, or where other “opening protective” considerations are required by Code.

  • Fire rated ceramic glass is required at A rated window assemblies.
  • ADA Manual Operators: ADA windows are not required to be operable by occupants if they are fire rated window assemblies.
  • Electronic Window Operators: Electronic operators which may be connected to the fire alarm system shall have fusible link installed.
  • Due to the weight of fire rated windows, often the required 5# operating force cannot be met. In those special circumstances where all the rooms in a classroom require fire rated window assemblies, the accessibility requirement may be waived upon CPS approval. As always, life safety takes precedence over accessibility needs.

Curtain Wall/Window Wall (Replacement)

Identify the materials, sizes, conditions, and structural supports for the system. Depending upon the extent of replacement and the availability of as-built drawings, a drawing prepared by a surveyor of the elevations might be necessary. Conform to the new construction guidelines for glass sizes in new installations. Verify and confirm that the existing conditions are adequate for curtain wall construction. In some instances what appears to be a curtain wall might be a vertical mullion system with inset window units. New replacement curtain wall system and storefront design shall consider site lines, and CPS guideline requirements for spacing and aesthetics. Depending on aesthetics and extent of the overall envelope, a new design approach may be considered following review and written approval with CPS stakeholders.

Lintels/Window Heads

The AOR shall review the existing conditions at the window heads during window replacement and repair projects. The existing window heads shall be repaired and waterproofed to CPS standards and window heads shall be repaired per the guidelines enumerated in the facade masonry renovation section. When determining the window repair scope, the AOR shall also review the existence of any previously installed panning and capping that may have been part of an earlier renovation project.

  • Lintels: Repairs or full replacement shall be identified and included as part of the window replacement scope. It is recommended to make one or more exploratory openings in masonry above lintels to determine the conditions of the lintels. Determine if the lintels are loose or attached to other structural elements. See further discussion of lintel replacement under Masonry Renovation Section in Chapter 2.2.2. Based on existing conditions, lintels shall typically be scraped and painted or replaced, with new flashing and end dams provided. For existing lintels to remain, removal of existing brick for remedial work may be required based on the condition of the existing masonry.
  • Sealant: An environmental consultant shall determine if any hazardous material requiring abatement are contained in the existing sealant. Identify and detail locations where new sealant and backer rod is required.
    • Curtain wall: Sealant and joints at existing curtain walls shall be reviewed by the AOR. Deteriorated sealant and joints shall be repaired during envelope renovations to ensure the envelope is not vulnerable to water infiltration through the curtain wall.
  • Window Sills: Identify window sills which are cracked, dislodged, broken, rusted, etc. and provide new flashing with end dams. Provide new limestone stills if the damaged window sills that are to be replaced are existing brick/masonry assemblies.

Louvers

Unless there is an upcoming mechanical project upgrade or facade repair project, the window replacement project shall also include replacement of louvers. Existing louvers and grilles shall be reviewed for location relative to grade and adjustments made if there is a concern regarding site grading. Check all seals and integral drainage. Code requires no fresh air intake below 10'-0" above finish grade for building ventilation systems.

Window A/C Units

Some schools without central air conditioning include installed window A/C units.

  • Requirements: The AOR/EOR shall determine if the existing window A/C units are still required and operational.
    • If the window A/C units are no longer required, the units shall be removed as part of the window replacement/repair project.
    • If the A/C units are required, the AOR/EOR shall confirm that the existing units are in the correct location(s). Where possible, existing A/C units, including associated outlets and conduit at the interior, may remain in the same location to avoid additional electrical relocation costs.
  • Accessories: All new/reinstalled window units shall have approved blank off panels and mounting brackets that meet CPS specifications. Provide accommodations in the new windows for A/C units to be properly installed by providing blank off panels and brackets. See CPS Master Details for brackets.
  • Salvaged/Reused: All window units that are determined to be salvaged and reused shall be reinstalled during a window replacement/repair project. AOR/EOR to provide notes in the Construction Documents for the General Contractor to coordinate the removal and storage of the existing A/C units with the Building Engineer. All window A/C units shall be tested prior to removal and all remote controls to be salvaged.

Window Guards

Identify all fixed window guards attached to the interior or exterior requiring repair or replacement. New construction criteria shall be utilized for the installation of new window guards. It is required to provide the manufacturer’s integral window guards at all windows on the first floor and, for security purposes, all upper story windows accessible to a low roof.

  • Existing curtain wall window guards /Security film: Where window guards are required, coordination with manufacturer’s requirements is required, an independently supported guard system or security film may be considered. The design strategy shall be reviewed with CPS and shall not void window wall/ curtain wall warranties.
  • Other locations: Additional locations which window guards shall be installed include windows facing a large field or a train track. Provide window guards with screens at locations identified by the Department of Public Health such as cafeterias and kitchens.

Window Treatments

When replacing windows, all existing window treatments shall be replaced with new, per CPS standard. For window repairs, replace older, damaged shades. In all cases, replace all shades within the same room. The extent of the shade replacement shall be made in the context of the overall exterior aesthetic.

  • Program spaces: Provide roll down, manually operated or electronically operated shades at all locations, except at corridors, stairs, auditorium, gymnasium and cafeteria unless otherwise noted.
  • Administrative Offices: Provide horizontal slat louvered blinds.
  • Auditorium/Gymnasium: Removal and re-installation of the auditorium window treatments is typically scoped during a window replacement project. Additional application of flame retardant is considered if removal/re-installation is required.

Interior Improvements

Window replacement projects shall coordinate the surrounding window surfaces of the interior spaces. Include patch and repair scope on the wall surfaces, window trim and ceiling areas. Impact to the space shall be minimal.

  • Bathrooms Projects/Toilet Rooms: Install opaque applied film on inside face of entire glass surface.