Ignition Resistant Eave Constructiondestruction of structures by fire in all cases. For more informationon eave construction or other fire code requirements, please refer to the -Urban

County of San Diego, Planning & Development Services

IGNITION RESISTANT EAVE CONSTRUCTION

BUILDING DIVISION

5510 OVERLAND AVE., SUITE 110, SAN DIEGO, CA 92123 ● (858) 565-5920 ● (888) 336-7553

HTTP://WWW.SDCPDS.ORG PDS 198 REV.: 01/01/2020 PAGE 1 of 6

GUIDANCE DOCUMENT

Since the 1980s, the County’s fire and building codes have been strengthened in successive code adoption cycles with the primary goal of protecting the safety of our citizens and enhancing a home’s ability to survive a wildfire. Although such measures protected many homes located within the areas impacted by the 2003 and 2007 wildfires, analysis of the burned homes identified areas where we could improve our codes; one of these areas is eave construction. Winds in wildfires carry huge amounts of burning embers, swirling into cracks and crevices, igniting anything that is combustible. Eaves, because they are perpendicular to the wall, tend to capture blowing embers. Eave vents, which are designed to move air in and out of the attic, give opportunity for embers to ignite soffit material or enter attic areas. Once a fire starts in an attic, it goes undetected for some time and is very difficult to stop even under ideal conditions. As a result, improvements were made to the County’s codes to establish a series of permissible ignition resistant eave construction details, see attached. Each detail can be downloaded individually in AutoCAD DWG file format at: http://www.co.san-diego.ca.us/pds/bldgforms/eaveindex.html. Eave construction on an addition may match the existing structure provided that the square footage of the addition does not exceed 50% of the existing structure or 2,500 square feet, whichever is less. The vents in these eaves must still comply with current County codes requiring resistance to intrusion of flames and embers.

Vents for enclosed attics, eave soffit spaces, enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters, underfloor vents, and vent openings in exterior walls and exterior doors shall be listed to ASTM E 2886 and comply with all of the following: (County Building code 92.1.706A.2, 92.1.707A5)

a. There shall be no flaming ignition of the cotton material during the Ember Intrusion Test. b. There shall be no flaming ignition during the Integrity Test portion of the Flame Intrusion

Test. c. The maximum temperature of the unexposed side of the vent shall not exceed 662

degrees Fahrenheit (350 degrees Celsius). While these standards will provide a high level of protection to structures built in the wildland-urban interface area, there is no guarantee that compliance with these standards will prevent damage or destruction of structures by fire in all cases. For more information on eave construction or other fire code requirements, please refer to the Wildland-Urban Interface – County Fire and Building Code Requirements (PDS #664) or contact the San Diego County Fire Authority at 858-974-5999.

http://www.co.san-diego.ca.us/pds/bldgforms/eaveindex.html

DETAIL 1

FASCIA PROTECTED

DATE: 01-01-2020

SCALE: NONE

FORM: PDS 198


GUIDANCE DOCUMENT - IGNITION RESISTANT EAVES

BUILDING DIVISION

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AutoCAD SHX TextMETAL DRIP EDGE

AutoCAD SHX TextNON-COMBUSTIBLE OR

AutoCAD SHX TextIGNITION RESISTANT MATERIAL

AutoCAD SHX Text FASCIA

DETAIL 2

FOAM TRIM

DATE: 01-01-2020

SCALE: NONE

FORM: PDS 198



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AutoCAD SHX Text FASCIA

AutoCAD SHX TextWITH COLOR COAT

AutoCAD SHX TextFOAM TRIM ENCLOSED



AutoCAD SHX TextSCRATCH & BROWN COAT

DETAIL 3

MODIFIED HEAVY TIMBER

DATE: 01-01-2020

SCALE: NONE

FORM: PDS 198



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AutoCAD SHX Text3x6 MINIMUM

AutoCAD SHX TextFASCIA OPTION USE

AutoCAD SHX Text4x6 MINIMUM

AutoCAD SHX TextEXPOSED RAFTER TAILS

AutoCAD SHX Text2x EXTERIOR GRADE

AutoCAD SHX TextT&G STARTER BOARDS



DETAIL 4

EXPOSED FASCIA

DATE: 01-01-2020

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FORM: PDS 198



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AutoCAD SHX Text2x FASCIA



AutoCAD SHX TextOR

AutoCAD SHX Text1 LAYER OF 5/8" TYPE X GYP BOARD

AutoCAD SHX TextOR

AutoCAD SHX TextNON-COMBUSTIBLE OR IGNITION

AutoCAD SHX Text2x BLOCK

AutoCAD SHX Text1 ADDITIONAL 2x BLOCK (2 TOTAL)

AutoCAD SHX TextRESISTANT MATERIAL

DETAIL 5

EXPOSED FIRE RETARDANT

TREATED WOOD FASCIA

DATE: 01-01-2020

SCALE: NONE

FORM: PDS 198



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AutoCAD SHX Text2x BACKING BLOCK

AutoCAD SHX Text2x FIRE RETARDANT PRESSURE

AutoCAD SHX TextTREATED LUMBER FASCIA


AutoCAD SHX Text%%uFIRE RETARDANT LUMBER%%u:

AutoCAD SHX TextUSE EITHER EXTERIOR FIRE-X RETARDANT TREATED LUMBER,

AutoCAD SHX TextCA SFM LISTING 2520-1701:100, %%uOR%%u FRX FIRE RETARDANT

AutoCAD SHX TextALL FIRE RETARDANT TREATED LUMBER SHALL NOT TO BE LEFT

AutoCAD SHX TextUNFINISHED.

AutoCAD SHX TextTREATED WOOD, ESR-1159.



pds198_partial_contentGUIDANCE DOCUMENT

pds198_partial_eave detailsDetail_01E - 2019-8.5x11.pdfSheets and Views8.5x11

Detail_03B_E - 2019-8.5x11.pdfSheets and Views8.5x11

Detail_04B_E - 2019-8.5x11.pdfSheets and Views8.5x11

Detail_07E - 2019-8.5x11.pdfSheets and Views8.5x11

Detail_11E - 2019-8.5x11.pdfSheets and Views8.5x11

Documents

Ignition Resistant Eave Constructiondestruction of structures by fire in all cases. For more informationon eave construction or other fire code requirements, please refer to the -Urban