The following language shall be inserted as a new Section 306:
"306 REROOFING
306.1 General.
Materials and methods of application used for roof recover and roof replacement shall comply with the requirements of Chapter 15 of the Chicago Building Code. Roof repair not exceeding 25 percent of the surface area of an existing roof may comply with Chapter 4 of this code.
Exceptions:
1. Roof replacement or roof recover of existing low-sloped roofs shall not be required to meet the minimum design slope requirement of one-quarter unit vertical in 12 units horizontal (2-percent slope) in Section 1507 of the Chicago Building Code for roofs that provide positive roof drainage.
2. Roof replacement or roof recover of existing low-sloped roofs shall comply with the roof insulation requirements for new construction unless the installation of additional insulation above the structural roof deck is infeasible due to the height of existing parapets, equipment curbs, skylight curbs, window sills, door thresholds, and similar elements with flashing into the roof system. In no case shall a roof replacement or roof recover reduce the insulating value of the roof.
3. Recovering or replacing an existing roof covering shall not be required to meet the requirement for secondary (emergency overflow) drains or scuppers in Section 1502 of the Chicago Building Code for roofs that provide for positive roof drainage. For the purposes of this exception, existing secondary drainage or scupper systems required in accordance with this code shall not be removed unless they are replaced by secondary drains or scuppers designed and installed in accordance with Section 1502 of the Chicago Building Code.
306.2 Structural requirements.
Reroofing shall comply with the requirements of Section 706.
Exception: For roof repair not exceeding 25 percent of the surface area of an existing roof, structural roof components shall be capable of supporting the roof-covering system and the material and equipment loads that will be encountered during installation of the system.
306.3 Roof replacement.
Roof replacement shall include the removal of all existing layers of roof coverings down to the roof deck.
Exception: Where the existing roof assembly includes an ice barrier membrane that is adhered to the roof deck, the existing ice barrier membrane shall be allowed to remain in place and be covered with an additional layer of ice barrier membrane in accordance with Section 1507 of the Chicago Building Code.
306.3.1 Roof recover.
The installation of a new roof covering over an existing roof covering shall be allowed where any of the following conditions occur:
1. The new roof covering is installed in accordance with the roof covering manufacturer’s instructions.
2. Complete and separate roofing systems, such as standing-seam metal roof panel systems, that are designed to transmit the roof loads directly to the building’s structural system and that do not rely on existing roofs and roof coverings for support, are installed.
3. Metal panel, metal shingle and concrete and clay tile roof coverings are installed over existing wood shake roofs in accordance with Section 306.4.
4. A new protective roof coating is applied over an existing protective roof coating, a metal roof panel, metal roof shingles, mineral-surfaced roll roofing, a built-up roof, modified bitumen roofing, thermoset and thermoplastic single-ply roofing or a spray polyurethane foam roofing system.
Exception: A roof recover shall not be allowed where any of the following conditions occur:
1. The existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.
2. The existing roof covering is slate, clay, cement or asbestos-cement tile.
3. The existing roof has two or more applications of any type of roof covering unless approved based on a condition report complying with Section 104 of the Chicago Minimum Requirements for Existing Buildings that establishes the capacity of the roof structure to support additional weight.
306.4 Roof recovering.
Where the application of a new roof covering over wood shingle or shake roofs creates a combustible concealed space, the entire existing surface shall be covered with gypsum board, mineral fiber, glass fiber or other approved materials securely fastened in place.
306.5 Reinstallation of materials.
Existing slate, clay or cement tile shall be allowed for reinstallation, except that damaged, cracked or broken slate or tile shall not be reinstalled. Existing vent flashing, metal edgings, drain outlets, collars and metal counterflashings shall not be reinstalled where rusted, damaged or deteriorated. Aggregate surfacing materials shall not be reinstalled.
306.6 Flashings.
Flashings shall be reconstructed in accordance with manufacturer’s installation instructions. Metal flashing to which bituminous materials are to be adhered shall be primed prior to installation."