The provisions of Section 706 of IEBC are adopted by reference with the following modifications:
1. Revise Section 706.1 to read:
"706.1 General.
Where alteration or repair work includes replacement of equipment that is supported by the building or reroofing, the provisions of this section shall apply."
2. Revise Section 706.2 to read:
"706.2 Addition or replacement of roofing or replacement of equipment.
Any existing gravity load-carrying structural element for which an alteration or repair causes an increase in design dead, live or snow load, including snow drift effects, of more than 5 percent shall be replaced or altered as needed to carry the gravity loads required by the Chicago Building Code for new structures.
Exceptions:
1. Buildings of Group R-5 occupancy where the altered building complies with the conventional light-frame construction methods of the Chicago Building Code.
2. Buildings in which the increased dead load is due entirely to the addition of a second layer of roof covering over an existing single layer of roof covering."
3. Revise Section 706.3 and its subsections to read:
"706.3 Additional requirements for reroofing of Risk Category IV buildings.
The requirements of this section shall apply to alteration or repair work involving reroofing of Risk Category IV buildings.
706.3.1 Bracing for unreinforced masonry bearing wall parapets.
Where a permit is issued for reroofing for more than 25 percent of the roof area of a building assigned to Risk Category IV that has parapets constructed of unreinforced masonry, the work shall include installation of parapet bracing unless a structural evaluation demonstrates compliance of such items. Reduced seismic forces shall be permitted.
706.3.2 Roof diaphragms resisting wind loads for Risk Category IV structures.
Where roofing materials are removed from more than 50 percent of the roof diaphragm or section of a Risk Category IV building, roof diaphragms, connections of the roof diaphragm to roof framing members, and roof-to-wall connections shall be evaluated for the wind loads specified in the Chicago Building Code, including wind uplift. If the diaphragms and connections in their current condition are not capable of resisting 75 percent of those wind loads, they shall be replaced or strengthened in accordance with the loads specified in the Chicago Building Code."