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Wildland Urban Interface Building Standards - CBC Chapter 7A Requirement

RE: 2010 California Residential Code, Section R327
        2010 California Building Code, Chapter 7A.

For permits applied for on or after January 1, 2008, all new buildings including commercial, one and two family dwellings, and detached ancillary buildings must comply with the new 2010 CRC Section R327 and 2010 CBC, Chapter 7A. New requirements are covered in this handout and must be included in the design of the proposed structure.

  • Under certain conditions commercial and industrial buildings may be exempted from these provisions by the local fire authority having jurisdiction.
  • Detached ancillary buildings, other than permitted qualified agricultural buildings, that exceed 500 sq. ft. or less than 50 ft. from the applicable building shall be made to meet the provisions of CRC, Section R327.1.3 or CBC, Chapter 7A and the requirements for the first 30 ft. of defensible space per CPRC 4291.
  • Rebuilding or remodeling existing buildings when the scope of work includes replacement of the roof covering, exterior siding, windows, and doors shall be considered “new buildings” and be required to comply with the provisions of CRC, Section R327 or CBC, Chapter 7A.
  • Decks requiring permits, regardless of whether the deck is associated with a building built under these provisions or not, shall meet the construction requirements of CRC, Section R327 or CBC, Chapter 7A and will be required to meet the defensible space provisions.
  1. Determine if your parcel is located in a Fire Severity Zone
  2. Approved products for 2010 CRC, Section R327& CBC, Chapter 7A Requirements
  3. Application: New buildings located in any Fire Hazard Severity Zone within State Responsibility Areas or any Wildland - Urban Interface Fire Area designated by the enforcing agency for which an application for a building permit is submitted, shall comply with the following sections:

Roofing

  • Roofs shall comply with the requirements of CRC, Section R327 or CBC, Chapter 7A and Chapter 9. Roofs shall have a roofing assembly installed in accordance with its listing and the manufacture’s installation instructions.
  • Roof coverings: Where the roof profile allows a space between the roof covering and roof decking, the spaces shall be constructed to prevent the intrusion of flames and ember, be fire stopped with approved materials or have one layer of No. 72 ASTM cap sheet installed over the combustible decking.
  • Roof Valleys: When provided, valley flashings shall be not less than 0.019-inch (No. 26 galvanized sheet gage) corrosion-resistant metal installed over a minimum 36” wide underlayment consisting of one layer of No. 72 ASTM cap sheet running the full length of the valley.
  • Roof Gutters: Roof gutters shall be provided with the means to prevent the accumulation of leaves and debris in the gutter.

Attic Ventilation

  • Eave or cornice vents: Vents shall not be installed in eaves and cornices.
  • Eave protection: Eaves and soffits shall meet the requirements of SFM 12-7A-3, CRC R327 or shall be protected by ignition-resistant materials or noncombustible construction on the exposed underside.

Exterior Coverings

  • Exterior walls shall be approved noncombustible or ignition-resistant material, heavy timber, or log wall construction or shall provide protection from the intrusion of flames and embers in accordance with standard SFM 127A-1.
  • Exterior wall coverings: Exterior wall coverings shall extend from the top of the foundation to the roof, and terminate at 2” nominal solid wood blocking between rafters at all roof overhangs, or in the case of enclosed eaves, terminate at the enclosure.
  • Exterior wall vents: Vent openings in exterior walls shall resist the intrusion of flame and embers into the structure or vents shall be screened with a corrosion-resistant, noncombustible wire mesh with 1/8” openings or its equivalent.
  • Exterior glazing and window walls: Exterior windows, window walls, glazed doors, and glazed openings within exterior doors shall be insulating-glass units with a minimum of one tempered pane, or glass block units, or have a fire-resistive rating of not less than 20 minutes, when tested according to ASTM E 2010.
  • Exterior door assemblies: Exterior door assemblies shall conform to the performance requirements of standard SFM 12-7A-1 or shall be approved noncombustible construction, or solid core wood having stiles and rails not less than 1-3/8” thick, or shall have a fire-resistance rating of not less than 20-minutes when tested according to ASTM E 2074. (Exception: noncombustible or exterior fire retardant treated wood vehicle access doors are not required to comply with this chapter.
  • Porch ceilings shall be approved noncombustible or ignition-resistant material.

Decking Floors and Underfloor Protection

  • Decking surfaces: Decking, surfaces, stair treads, risers a, and landings of decks, porches, and balconies where any portion of such surface is within 10’ of the primary structure shall comply with one of the following:
    1. Shall be constructed of ignition-resistant materials and pass the performance requirements of SFM 12-7A-4.
    2. Shall be constructed with heavy timber, exterior fire-retardant-treated wood or approved noncombustible materials.
    3. The use of paints, coatings, stains, or other surface treatments are not an approved method of protection as required in this chapter

Underfloor and Appendages Protection

  • Decking surfaces: Decking, surfaces, stair treads, risers a, and landings of decks, porches, and balconies where any portion of such surface is within 10’ of the primary structure shall comply with one of the following:
    1. Shall be constructed of ignition-resistant materials and pass the performance requirements of SFM 12-7A-4.
    2. Shall be constructed with heavy timber, exterior fire-retardant-treated wood or approved noncombustible materials.
    3. The use of paints, coatings, stains, or other surface treatments are not an approved method of protection as required in this chapter.
  • Underfloor and Appendages Protection
  • Underside of appendages and floor projections: The underside of cantilevered and overhanging appendages and floor projections shall maintain the ignition-resistant integrity of exterior walls, or the projection shall be enclosed to the grade.
  • Unenclosed under floor protection: buildings shall have all under floor areas enclosed to the grade the same as exterior wall requirements. (Exception) The complete enclosure of under floor areas may be omitted where the underside of all exposed floors, exposed structural columns, beams and supporting walls are protected as required with exterior ignition-resistant material construction or be heavy timber.

Defensible Space

  • Prior to building permit final approval the property shall be in compliance with the vegetation clearance requirements prescribed in California Public Resources Code 4291 California government Code Section 51182.
  • The enforcement of defensible space and inspection shall be performed by the local fire jurisdiction having authority.
  • See Cal-Fire handouts for how to obtain defensible space zones which include: Firebreak within 30’ and 100' of each building or structure, dead and dying woody surface fuels shall be removed, down logs or stumps, fuel separation, and defensible space with continuous tree canopy.
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