R4502.1 General. The work shall not cause the building or structure to become unsafe or adversely affect the performance of the building; shall not cause an existing mechanical or plumbing system to become unsafe, hazardous, insanitary, or overloaded; and unless expressly permitted by these provisions, shall not make the building any less compliant with this code or to any previously approved alternative arrangements than it was before the work was undertaken.

R4502.2 Structural. Structural elements and systems that are altered, repaired, or replaced shall comply with the structural provisions of this chapter and of Chapter 3 through Chapter 10 of the International Residential Code unless noted otherwise.

R4502.2.1 Minimum design loads. The minimum design loads for the structure shall be the loads applicable at the time the building was constructed. The minimum design loads for the structural components shall comply with the International Residential Code. Structural elements that are uncovered during the course of the alteration and that are found to be unsafe shall be repaired in accordance with Section R102.7.1.

R4502.2.2 Unreinforced masonry parapet bracing. Unreinforced masonry buildings located in Seismic Design Category D0, D1, or D2 shall have parapet bracing and wall anchors installed at the roofline whenever a reroofing permit is issued. Such parapet bracing and wall anchors shall be of an approved design unless an evaluation demonstrates compliance of the existing bracing and anchorage.

R4502.3 Smoke alarms. Smoke alarms shall be provided in accordance with Section R314.2.2.

R4502.4 Carbon monoxide alarms. Carbon monoxide alarms shall be provided in accordance with Section R315.2.2.

R4502.5 Replacement windows. Where an existing window, including the sash and glazed portion, or safety glazing is replaced, the replacement window or safety glazing shall comply with the requirements of Sections 4502.5.1 through 4502.5.5 as applicable.

R4502.5.1 Energy efficiency. Replacement windows shall comply with the requirements of the Washington State Energy Code-Residential.

R4502.5.2 Safety glazing. Replacement glazing in hazardous locations shall comply with the safety glazing requirements of Section R308.

R4502.5.3 Window fall protection. Window fall protection shall be installed in accordance with Section R312.2.

R4502.5.4 Replacement windows for emergency escape and rescue openings. Replacement windows shall be exempt from Sections R310.2 and R310.4.4, provided that the replacement window meets the following conditions:

1. The replacement window is the manufacturer's largest standard size window that will fit within the existing frame or existing rough opening. The replacement window is of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.

2. The replacement window is not part of a change of use.

R4502.5.5 Window opening control device and fall protection device height. Window opening control devices or fall protection device shall be located at a height in accordance with Section R310.1.1 or at as low a height as can be installed within the existing clear opening.

R4502.6 Flood hazard areas. Work performed in existing buildings located in a flood hazard area as established by Table R301.2 shall be subject to the provisions of Section R105.3.1.1.