101.5 Additions or alterations. Additions or alterations may be made to any building or structure without requiring the existing building or structure to comply with all of the requirements of this code, provided the addition or alteration conforms to that required for a new building or structure.

EXCEPTION:

Provisions of this code that specifically apply to existing conditions are retroactive. See Sections 402.3, 601.1 and Appendix A.

Additions or alterations shall not cause the existing building or structure to become unsafe. An unsafe condition shall be deemed to have been created if an addition or alteration will cause the existing building or structure to become structurally unsafe or overloaded; will not provide adequate access in compliance with the provisions of this code or will obstruct existing exits or access; will create a fire hazard; will reduce required fire resistance or will otherwise create conditions dangerous to human life.

108.3 Site plan. In addition to the requirements for plans in the International Building Code, the code official may require site plans which include topography, width and percent of grade of access roads, landscape and vegetation details, locations of structures or building envelopes, existing or proposed overhead utilities, occupancy classification of buildings, types of ignition resistant construction of buildings, structures and their appendages, roof classification of buildings, and site water supply systems. The code official is authorized to waive or modify the requirement for a site plan.

108.4 Vegetation management plans. When required by the code official or when utilized by the permit applicant pursuant to Section 502, vegetation management plans shall be prepared and shall be submitted to the code official for review and approval as part of the plans required for a permit. See Appendix B.

108.7 Vicinity plan. When required by the code official, the requirements for site plans shall include details regarding the vicinity within 300 feet (91,440 mm) of property lines, including other structures, slope, vegetation, fuel breaks, water supply systems and access roads.

402.1.1 Access. New subdivisions, as determined by this jurisdiction, shall be provided with fire apparatus access roads in accordance with the International Fire Code.

402.1.2 Water supply. New subdivisions, as determined by this jurisdiction, shall be provided with water supply in accordance with the International Fire Code.

402.2 Individual structures. Individual structures shall comply with Sections 402.2.1 and 402.2.2.

402.2.1 Access. Individual structures hereafter constructed or relocated into or within wildland-urban interface areas shall be provided with fire apparatus access in accordance with the International Fire Code.

402.2.2 Water supply. Individual structures hereafter constructed or relocated into or within wildland-urban interface areas shall be provided with a conforming water supply in accordance with the International Fire Code.

EXCEPTIONS:	1. Structures constructed to meet the requirements for the class of ignition-resistant construction specified in Table N503.1 for a nonconforming water supply.
	2. Buildings containing only private garages, carports, sheds and agricultural buildings with a floor area of not more than 600 square feet (56 m2).

402.3 Existing conditions. Existing address markers, roads and fire protection equipment shall be in accordance with the International Fire Code.

Table 503.1

Ignition-Resistant Constructiona

	Fire Hazard Severity
	Moderate Hazard		High Hazard		Extreme Hazard
	Water Supplyb		Water Supplyb		Water Supplyb
Defensible Spacec	Conforming	Nonconforming	Conforming	Nonconforming	Conforming	Nonconforming
Nonconforming	IR 2	IR 1	IR 1	IR 1 N.C.	IR 1 N.C.	Not Permitted
Conforming	IR 3	IR 2	IR 2	IR 1	IR 1	IR 1 N.C.
1.5 x Conforming	Not Required	IR 3	IR 3	IR 2	IR 2	IR 1

	aAccess shall be in accordance with Section 402.
	bWater supply shall be in accordance with Section 402.1.
	IR 1 = Ignition-resistant construction in accordance with Section 504.
	IR 2 = Ignition-resistant construction in accordance with Section 505.
	IR 3 = Ignition-resistant construction in accordance with Section 506.
	N.C. = Exterior walls shall have a fire-resistance rating of not less than 1 hour and the exterior surfaces of such walls shall be noncombustible. Usage of log wall construction is allowed.
	c Conformance based on Section 603.

403 Access. This section not adopted.

404 Water supply. This section not adopted.

appendix b-vegetation management plan - this appendix is adopted.

appendix D-fire danger rating system - this appendix is adopted.

PDFWAC 51-54A-8200

International Wildland-Urban Interface Code.