The purpose of this chapter is to establish minimum regulations consistent with nationally recognized good practice for the safeguarding of life and property protection and to establish required construction materials, methods and planning associated with a structure's ability to withstand exposure to wildfire events consistent with RCW 19.27.560 and Chelan County Fire District No. 3 recommendations.
(Ord. 1626 § 1 (Att. A), 2021)
The design and construction of structures shall comply with the provisions of this chapter along with the current provisions contained within the International Fire Code, International Building Code, International Residential Code and Leavenworth Municipal Code. Should any provision within this chapter conflict with any other provision of the Leavenworth Municipal Code, then this chapter shall control.
(Ord. 1626 § 1 (Att. A), 2021)
The building official shall have the authority to render interpretations of this chapter and to adopt policies and procedures in order to clarify the application of its provisions. Such interpretations, policies and procedures shall be in accordance with the intent and purpose of this chapter and in conformance with guidelines referenced in the ICC International Wildland-Urban Interface Code.
(Ord. 1626 § 1 (Att. A), 2021)
The provisions of this section shall apply to all new construction and alteration, movement, repair or maintenance when such alteration, repair or maintenance modifies any of the following components. The provisions of this section do not apply to storage sheds exempt from a building permit.
A. 
Roof Covering (RCW 19.27.560(1)(a)(i)).
1. 
Roofs shall have a roof assembly that complies with class A rating when testing in accordance with American Society for Testing Materials E 108 or Underwriters Laboratories 790. For roof coverings where the profile allows a space between the roof covering and roof decking, the space at the eave ends shall be fire stopped to preclude entry of flames or embers, or have one layer of 72 pound mineral-surfaced, nonperforated cap sheet complying with American Society for Testing Materials D 3909 installed over the combustible decking.
2. 
The roof covering on buildings or structures in existence prior to the adoption of the wildland-urban interface code under this chapter that are replaced or have 50 percent or more replaced in a 12-month period shall be replaced with a roof covering required for new construction.
3. 
The roof covering on any addition to a building or structure shall be replaced with a roof covering required for new construction.
B. 
Protection of Eaves, Soffits, and Fascias (IWUIC 504.3). Eaves and soffits shall be protected on the exposed underside by ignition-resistant materials or by materials approved for not less than one-hour fire-resistance-rated construction, two-inch nominal dimension lumber, or one-inch nominal fire-retardant-treated lumber or three-quarter-inch nominal fire-retardant-treated plywood, identified for exterior use and meeting the requirements of Section 2303.2 of the International Building Code. Fascias are required and shall be protected on the backside by ignition-resistant materials or by materials approved for not less than one-hour fire-resistance-rated construction or two-inch nominal dimension lumber.
C. 
Gutters and Downspouts (IWUIC 504.4). Gutters and downspouts shall be constructed of noncombustible material. Gutters shall be provided with an approved means to prevent the accumulation of leaves and debris in the gutter.
D. 
Exterior Walls (RCW 19.27.560(1)(a)(ii)). Exterior walls of buildings or structures shall be constructed with one of the following methods. Such materials shall extend from the top of the foundation to the underside of the roof sheathing.
1. 
Materials approved for not less than one-hour fire-resistance-rated construction on the exterior side;
2. 
Approved noncombustible materials;
3. 
Heavy timber or log wall construction;
4. 
Fire retardant-treated wood on the exterior side. The fire retardant-treated wood shall be labeled for exterior use and meet the requirements of Section 2303.2 of the International Building Code; or
5. 
Ignition-resistant materials on the exterior side.
E. 
Replacement or Repair of Siding. (Added to address fire exposure – WAC 51-54A-8200 Appendix N: 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.)
Siding coverings on buildings or structures in existence prior to the adoption of this code that are replaced or have 50 percent or more replaced in a 12-month period shall be replaced with a siding material as required for new construction based on the requirements listed in subsection (D) of this section.
F. 
Underfloor Enclosure (IWUIC 504.5). Buildings or structures shall have underfloor areas enclosed to the ground with exterior walls in accordance with subsection (D) of this section.
Exception: Complete enclosure shall not be required where the underside of exposed floors and exposed structural columns, beams and supporting walls are protected as required for exterior one-hour fire-resistance-rated construction or heavy timber construction or fire-retardant treated wood. The fire-retardant-treated wood shall be labeled for exterior use and meet the requirements of Section 2303.2 of the International Building Code.
G. 
Appendages and Projections (RCW 19.27.560(1)(a)(iii)). Unenclosed accessory structures attached to buildings with habitable spaces and projections, such as decks, shall not be less than one-hour fire-resistance rated construction, heavy timber construction, or constructed of one of the following:
1. 
Approved noncombustible materials;
2. 
Fire retardant-treated wood identified for exterior use and meeting the requirements of Section 2303.2 of the International Building Code; or
3. 
Ignition-resistant building materials in accordance with Section 503.2 of the International Wildland-Urban Interface Code.
This section does not apply to an unenclosed accessory structure attached to buildings with habitable spaces and projections, such as decks, attached to the first floor of a building if the structure is built with building materials at least two inches nominal depth and the area below the unenclosed accessory structure is screened with wire mesh screening to prevent embers from coming in from underneath or exterior wall construction defined in subsection (D) of this section to within six inches of the ground (per RCW 19.27.560).
H. 
Vents (IWUIC 504.10). Attic ventilation openings, foundation or underfloor vents, or other ventilation openings in vertical exterior walls and vents through roofs shall not exceed 144 square inches each. Such vents shall be covered with noncombustible corrosion-resistant mesh with openings not to exceed one-eighth inch (per International Residential Code R408.2), or shall be designed and approved to prevent flame or ember penetration into the structure.
Air intake into structures shall be covered with metal wire mesh with openings that do not exceed one-eighth inch. Such air intake openings shall connect to 26-gauge metal ducts for a minimum of six feet in length from the intake. Exhaust termination shall be metal with an integral backdraft damper at the termination point.
I. 
Vent Location (IWUIC 504.10.1). All vents shall meet the requirements of subsection (H) of this section and the following:
1. 
Attic ventilation openings shall not be located in soffits, in eave overhangs, between rafters at eaves, or in other overhang areas.
2. 
Gable end and dormer vents shall be located not less than 10 feet from lot lines.
3. 
Underfloor ventilation openings shall be located as close to grade as practical.
Exceptions: Attic ventilation openings in soffits, eave overhangs, between rafters at eaves or in other overhang areas that meet flame- and ember-resistant listed vents complying with ASTM E2886 or CalFire SFM12-7A.
(Ord. 1626 § 1 (Att. A), 2021)
Driveways shall be provided where any portion of an exterior wall of the first story of the building is located more than 150 feet from a fire apparatus access road. Driveways in excess of 300 feet in length shall be provided with turnarounds and driveways in excess of 500 feet in length and less than 20 feet in width shall be provided with turnouts and turnarounds. The community development director, in consultation with the fire district, will define the requirements for a turnout or turnaround as required in this section.
(Ord. 1626 § 1 (Att. A), 2021)
The following wildland-urban interface home hardening recommendations for fire-resistant structures and landscapes will be provided to property owners in the city who are encouraged to take minimum steps to improve resiliency of their property in case of fire. These actions do not ensure that a structure will survive a wildfire, but they can help.
A. 
Location Access.
1. 
Street address is clearly marked and visible from the street with reflective numbers. Chelan County Fire District No. 3 can assist with ordering blue address signs with reflective numbers.
B. 
Additional Building Standards.
1. 
Enclose soffits, attic vents and other openings with at least one-eighth-inch metal screening.
2. 
Enclose under decks with a solid skirt or lattice backed with at least one-eighth-inch metal screening.
3. 
Separate wood fences from structure with a four-foot section of nonflammable fencing.
C. 
Minimum Landscaping Recommendations.
1. 
Remove leaves and debris from gutters, roofs, overhangs and under decks.
2. 
Keep yards free of dead leaves, twigs, and branches. Mow dead weeds and grass early.
3. 
Prune overhanging branches and branches touching your roof to create at least a 10-foot separation.
4. 
Maintain a five-foot radius clear of flammable vegetation around structures. Reference, Fire-Resistant Plants for Home Landscapes, 2006 Pacific Northwest Extension publication.
5. 
Plant fire-resistive vegetation without wood mulch, outside the five-foot radius of structures.
6. 
Stack firewood and flammable materials at least 10 feet away from structures.
(Ord. 1626 § 1 (Att. A), 2021)