CBC · California Building Code

How are snow loads determined and where are ground-snow values found?

The CBC requires designers to use ASCE 7 or the CBC’s 1608.2 figures/tables to get the ground snow load (p_g). For allowable‑stress design, convert that number with p_g(asd) = 0.7 × p_g; Alaska and Hawaii have special rules and any site‑specific study must follow ASCE 7 and be approved by the building official.

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Last reviewed: July 5, 2026

What the code requires — 2–4 sentences

The CBC requires that design snow loads be determined in accordance with Chapter 7 of ASCE 7 and that roof design loads not be less than the loads required by Section 1607; this overall requirement is stated in § 1608.1. The ground‑snow values used to develop roof design loads must come from the reliability‑targeted ground snow values in ASCE 7 or from the CBC’s Figures 1608.2(1)–1608.2(4) for the contiguous U.S. or Table 1608.2 for Alaska, with site‑specific case studies per ASCE 7 and building‑official approval where required (§ 1608.2). Where an allowable‑stress design (ASD) ground snow load is required, the CBC mandates conversion using p_g(asd) = 0.7 · p_g (§ 1608.2.1).

Requirements in detail

Where the controlling ground‑snow numbers come from

  • Contiguous United States: use the CBC figures (Figures 1608.2(1)–1608.2(4)) or ASCE 7 Chapter 7 reliability‑targeted values. § 1608.2 requires those sources.
  • Alaska: use Table 1608.2 (state table of p_g values for Alaskan locations). § 1608.2 refers to Table 1608.2 for Alaska.
  • Hawaii: snow loads are zero except in mountainous regions as approved by the building official; § 1608.2 states this exception.

Conversion to allowable‑stress‑design (ASD) ground snow

  • If an ASD ground snow load is required, convert per § 1608.2.1 using the explicit CBC equation:
    • p_g(asd) = 0.7 · p_g (§ 1608.2.1).

Site‑specific studies and official approval

  • Site‑specific case studies must be determined according to Chapter 7 of ASCE 7 and approved by the building official (§ 1608.2).

Quick reference table (decision‑relevant items)

Decision item Typical value or source When to use it Code Reference
Source of p_g for contiguous U.S. Figures 1608.2(1)–(4) or ASCE 7 Chapter 7 For most sites in the lower 48 § 1608.2
Source of p_g for Alaska Table 1608.2 (Alaskan locations) For locations listed in the Table; includes elevation notes § 1608.2
Hawaii p_g = 0 except mountainous areas approved by official Only where local mountainous snowfall applies § 1608.2
ASD conversion p_g(asd) = 0.7 · p_g When allowable‑stress design values are required § 1608.2.1
Site‑specific cases ASCE 7 Chapter 7 methodology and building‑official approval When local conditions differ from map/table § 1608.2

Exceptions & special cases

  • Site‑specific ground‑snow studies: the CBC allows site‑specific studies using ASCE 7 procedures, but they must be approved by the building official (§ 1608.2).
  • Hawaii: by default p_g = 0; mountainous regions with snow are exceptions only if approved by the building official (§ 1608.2).
  • Alaska elevation notes and adjustments: Table 1608.2 contains elevation‑based entries and footnotes (e.g., increases above cited elevations for some Alaska locations); see Table 1608.2 itself for the elevation rules (§ 1608.2).

Common mistakes

  • Failing to use the prescribed map/table or ASCE 7 values: designers sometimes substitute non‑code maps instead of Figures 1608.2(1)–(4), Table 1608.2 or ASCE 7—§ 1608.2 requires those sources.
  • Forgetting to convert to ASD when required: neglecting the p_g(asd) = 0.7·p_g conversion when designing with allowable‑stress values violates § 1608.2.1.
  • Treating Hawaii as snowy without approval: assuming non‑zero p_g in Hawaii without building‑official approval contradicts § 1608.2.
  • Skipping building‑official approval for site‑specific studies: site studies must follow ASCE 7 and be approved per § 1608.2.

Worked example — applying the rule with numbers

Scenario: The designer reads the CBC figure (or ASCE 7 geodatabase) and determines the reliability‑targeted ground snow load for a site is p_g = 30 psf.

  1. Determine whether ASD values are needed. If the roof design or methodology calls for allowable‑stress design ground snow, convert as required by § 1608.2.1:
    p_g(asd) = 0.7 · p_g = 0.7 · 30 psf = 21.0 psf. § 1608.2.1 mandates this conversion.

  2. Use p_g (or p_g(asd) as appropriate) as the input to the ASCE 7 roof‑snow procedures to compute flat‑roof snow, exposure, slope factors, drifts, etc., per ASCE 7 and CBC direction in § 1608.1 and § 1608.2. § 1608.1 requires design snow loads per ASCE 7.

(If the site instead had p_g = 0 because it is in Hawaii and not in an approved mountainous region, no snow load would be used per § 1608.2.)

Related provisions

  • § 1608.1 — General requirement that design snow loads follow ASCE 7 (and roof loads not be less than § 1607).
  • § 1608.2 — Ground snow loads sources: ASCE 7 or Figures 1608.2(1)–(4) and Table 1608.2 for Alaska; Hawaii exception and site‑specific approval.
  • § 1608.2.1 — Conversion of p_g to p_g(asd) using p_g(asd) = 0.7 · p_g.
  • § 1608.3 — Ponding instability on roofs (evaluation per ASCE 7).
  • § 1603.1.3 — Construction document requirements (including indication of p_g and p_g(asd) and additional roof‑snow data when p_g exceeds 15 psf).
  • § 3103.6.1.1 — Temporary public‑occupancy structures: modification factors and requirements for snow loads reference § 1608.

Code references

Grounded in the retrieved California Building Code — click a citation to read the verbatim passage:

  • CBC § 1608.1 High relevance — show source text

    SECTION 1608—SNOW LOADS

    1608.1 General. Design snow loads shall be determined in accordance with Chapter 7 of ASCE 7, but the design roof load shall be not less than that determined by Section 1607.

    Exception: Temporary structures complying with Section 3103.6.1.1.

    1608.2 Ground snow loads. The ground snow loads to be used in determining the design snow loads for roofs shall be determined in accordance with the reliability-targeted (strength based) ground snow load values in Chapter 7 of ASCE 7 or Figures 1608.2(1) through 1608.2(4) for the contiguous United States and Table 1608.2 for Alaska. Site-specific case studies shall be determined in accordance with Chapter 7 of ASCE 7 and shall be approved by the building official. Snow loads are zero for Hawaii, except in mountainous regions as approved by the building official.

    TABLE 1608.2—GROUND SNOW LOADS, p, FOR ALASKAN LOCATIONS
    g    		 Col2 Col3 Col4 Col5 Col6
    CITY/TOWN ELEVATION (ft) GROUND SNOW LOAD,****pg
    a, b, c (lb/ft2)    		 GROUND SNOW LOAD,****pg
    a, b, c (lb/ft2)    		 GROUND SNOW LOAD,****pg
    a, b, c (lb/ft2)    		 GROUND SNOW LOAD,****pg
    a, b, c (lb/ft2)
    CITY/TOWN ELEVATION (ft) RISK CATEGORY RISK CATEGORY RISK CATEGORY RISK CATEGORY
    CITY/TOWN ELEVATION (ft) I II III IV
    Adek 100 32 40 46 50
    Anchorage/Eagle Riverc 500 64 80 92 100
    Arctic Village 2,100 38 48 55 60
    Bethel 100 51 64 74 80
    Bettles 700 102 128 147 160
    Cantwell 2,100 109 136 156 170
    Cold Bay 100 45 56 64 70
    Cordova 100 128 160 184 200
    Deadhorse 100 32 40 46 50
    Delta Junction 400 51 64 74 80
    Dillingham 100 141 176 202 220
    Emmonak 100 128 160 184 200
    Fairbanks 1,200 77 96 110 120
    Fort Yukon 400 64 80 92 100
    Galena 200 77 96 110 120
    Girdwood 200 179 224 258 280
    Glennallen 1,
  • CBC § 3103.6.1.1. High relevance — show source text

    1608 A .1 General. Design snow loads shall be determined in accordance with Chapter 7 of ASCE 7, but the design roof load shall be not less than that determined by Section 1607 A . Exception: Temporary structures complying with Section 3103.6.1.1. 1608 A .2 Ground snow loads. The ground snow loads to be used in determining the design snow loads for roofs shall be determined in accordance with the reliability-targeted (strength based) ground snow load values in Chapter 7 of ASCE 7 or Figures 1608 A .2(1) through 1608 A .2(4) for the contiguous United States. Site-specific case studies shall be determined in accordance with Chapter 7 of ASCE 7 and shall be approved by the building official.

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    1608 A .2.1 Ground snow conversion. Where required, the ground snow loads, p g, of Figures 1608 A .2(1) through 1608 A .2(4) and Table 1608 A .2 shall be converted to allowable stress design ground snow loads, p g(asd), using Equation 16 A -17. Equation 16 A -17 p g(asd) = 0.7 p g

    where:

    p g(asd) = Allowable stress design ground snow load. p g = Ground snow load determined from Figures 1608 A .2(1) through 1608 A .2(4) and Table 1608 A .2. 1608 A .3 Ponding instability. Ponding instability on roofs shall be evaluated in accordance with ASCE 7.

    1608A.4 Determination of snow loads. [DSA-SS] The ground snow load or the design snow load for roofs shall conform with the adopted ordinance of the city, county, or city and county in which the project site is located, and shall be approved by DSA. See Section 106.1.2 for snow load posting requirements.

    SECTION 1609 A —WIND LOADS

  • CBC § 16-17 High relevance — show source text

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    trusses with web configurations capable of accommodating an assumed rectangle 42 inches (1067 mm) in height by 24 inches (610 mm) in width, or greater, within the plane of the trusses. The live load in Table 1607.1 need only be applied to those portions of the joists or truss bottom chords where both of the following conditions are met:

    1. The attic area is accessed from an opening not less than 20 inches (508 mm) in width by 30 inches (762 mm) in length that is located where the clear height in the attic is not less than 30 inches (762 mm).
    2. The slope of the joists or truss bottom chords is not greater than 2 units vertical in 12 units horizontal.

    The remaining portions of the joists or truss bottom chords shall be designed for a uniformly distributed concurrent live load of not less than 10 pounds per square foot (0.48 kN/m [2] ).

    1607.21.3 Attics served by stairs. Attic spaces served by stairways other than the pull-down type shall be designed to support the minimum live load specified for habitable attics and sleeping rooms.

    SECTION 1608—SNOW LOADS

    1608.1 General. Design snow loads shall be determined in accordance with Chapter 7 of ASCE 7, but the design roof load shall be not less than that determined by Section 1607.

    Exception: Temporary structures complying with Section 3103.6.1.1.

    1608.2 Ground snow loads. The ground snow loads to be used in determining the design snow loads for roofs shall be determined in accordance with the reliability-targeted (strength based) ground snow load values in Chapter 7 of ASCE 7 or Figures 1608.2(1) through 1608.2(4) for the contiguous United States and Table 1608.2 for Alaska. Site-specific case studies shall be determined in accordance with Chapter 7 of ASCE 7 and shall be approved by the building official. Snow loads are zero for Hawaii, except in mountainous regions as approved by the building official.

    TABLE 1608.2—GROUND SNOW LOADS, p, FOR ALASKAN LOCATIONS
    g    		 Col2 Col3 Col4 Col5 Col6
    CITY/TOWN ELEVATION (ft) GROUND SNOW LOAD,****pg
    a, b, c (lb/ft2)    		 GROUND SNOW LOAD,****pg
    a, b, c (lb/ft2)    		 GROUND SNOW LOAD,****pg
    a, b, c (lb/ft2)    		 GROUND SNOW LOAD,****pg
    **a, b,
  • CBC § 12.4 High relevance — show source text

    D = Dead load.

    D i = Weight of ice in accordance with Chapter 10 of ASCE 7.

    E = Combined effect of horizontal and vertical earthquake induced forces as defined in Section 12.4 of ASCE 7.

    F = Load due to fluids with well-defined pressures and maximum heights.

    F a = Flood load in accordance with Chapter 5 of ASCE 7.

    H = Load due to lateral earth pressures, ground water pressure or pressure of bulk materials.

    L = Live load.

    L r = Roof live load. p g(asd) = Allowable stress design ground snow load. p g = Ground snow load determined from Figures 1608.2(1) through 1608.2(4) and Table 1608.2.

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    R = Rain load.

    S = Snow load.

    T = Cumulative effects of self-straining load forces and effects.

    V asd = Allowable stress design wind speed, mph (m/s) where applicable.

    V = Basic wind speed, V, mph (m/s) determined from Figures 1609.3(1) through 1609.3(4) or ASCE 7.

    V T = Tornado speed, mph (m/s) determined from Chapter 32 of ASCE 7.

    W = Load due to wind pressure.

    W i = Wind-on-ice in accordance with Chapter 10 of ASCE 7.

    SECTION 1603—CONSTRUCTION DOCUMENTS

    1603.1 General. Construction documents shall show the material, size, section and relative locations of structural members with floor levels, column centers and offsets dimensioned. The design loads and other information pertinent to the structural design required by Sections 1603.1.1 through 1603.1.9 shall be indicated on the construction documents.

    Exception: Construction documents for buildings constructed in accordance with the conventional light-frame construction provisions of Section 2308 shall indicate the following structural design information:

    1. Floor and roof dead and live loads.

    2. Ground snow load, p g, and allowable stress design ground snow load, p g(asd) .

    3. Basic wind speed, V, mph (m/s), and allowable stress design wind speed, V asd , as determined in accordance with Section 1609.3.1 and wind exposure.

    4. Seismic design category and site class.

    5. Flood design data, if located in flood hazard areas established in Section 1612.3.

    6. Design load-bearing values of soils.

    7. Rain load data.

    [OSHPD 1R, 2 & 5] Additional requirements are included in Sections 7-115 and 7-125 of the California Administrative Code (Part 1, Title 24, C.C.R).

    1603.1.1 Floor live load. The uniformly distributed, concentrated and impact floor live load used in the design shall be indicated for floor areas. Use of live load reduction in accordance with Section 1607.13 shall be indicated for each type of live load used in the design.

  • CBC § 1608.2 High relevance — show source text

    L = Live load.

    L r = Roof live load.

    p g(asd) = Allowable stress design ground snow load.

    p g = Ground snow load determined from Figures 1608.2(1) through 1608.2(4) and Table 1608.2.

    R = Rain load.

    S = Snow load.

    T = Cumulative effects of self-straining load forces and effects.

    V asd = Allowable stress design wind speed, mph (m/s) where applicable.

    V = Basic wind speed, V, mph (m/s) determined from Figures 1609 A .3(1) through 1609 A .3(4) or ASCE 7.

    V T = Tornado speed, mph (m/s) determined from Chapter 32 of ASCE 7.

    W = Load due to wind pressure.

    W i = Wind-on-ice in accordance with Chapter 10 of ASCE 7.

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    SECTION 1603 A —CONSTRUCTION DOCUMENTS

    1603 A .1 General. Construction documents shall show the material, size, section and relative locations of structural members with floor levels, column centers and offsets dimensioned. The design loads and other information pertinent to the structural design required by Sections 1603 A .1.1 through 1603 A .1.10 shall be indicated on the construction documents.

    Exception: Construction documents for buildings constructed in accordance with the conventional light-frame construction provisions of Section 2308 shall indicate the following structural design information:

    1. Floor and roof dead and live loads.

    2. Ground snow load, p g, and allowable stress design ground snow load, p g(asd) .

    3. Basic wind speed, V, mph (m/s), and allowable stress design wind speed, V asd , as determined in accordance with Section 1609 A .3.1 and wind exposure.

    4. Seismic design category and site class.

    5. Flood design data, if located in flood hazard areas established in Section 1612 A .3.

    6. Design load-bearing values of soils.

    7. Rain load data.

    [DSA-SS] Additional requirements are included in Section 4-210 and 4-317 of the California Administrative Code (Part 1, Title 24, C.C.R).

    [OSHPD 1] Additional requirements are included in Section 7-115 and 7-125 of the California Administrative Code.

    1603 A .1.1 Floor live load. The uniformly distributed, concentrated and impact floor live load used in the design shall be indicated for floor areas. Use of live load reduction in accordance with Section 1607 A .13 shall be indicated for each type of live load used in the design.

  • CBC § 21.2 High relevance — show source text

    The live load in Table 1607 A .1 need not be assumed to act concurrently with any other live load requirement. 1607 A .21.2 Uninhabitable attics with storage. In residential occupancies, uninhabitable attic areas with storage are those where the maximum clear height between the joist and rafter is 42 inches (1067 mm) or greater, or where there are two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches (1067 mm) in height by 24 inches (610 mm) in width, or greater, within the plane of the trusses. The live load in Table 1607 A .1 need only be applied to those portions of the joists or truss bottom chords where both of the following conditions are met:

    1. The attic area is accessed from an opening not less than 20 inches (508 mm) in width by 30 inches (762 mm) in length that is located where the clear height in the attic is not less than 30 inches (762 mm).
    2. The slope of the joists or truss bottom chords is not greater than 2 units vertical in 12 units horizontal. The remaining portions of the joists or truss bottom chords shall be designed for a uniformly distributed concurrent live load of not less than 10 pounds per square foot (0.48 kN/m [2] ). 1607 A .21.3 Attics served by stairs. Attic spaces served by stairways other than the pull-down type shall be designed to support the minimum live load specified for habitable attics and sleeping rooms.

    SECTION 1608 A —SNOW LOADS

    1608 A .1 General. Design snow loads shall be determined in accordance with Chapter 7 of ASCE 7, but the design roof load shall be not less than that determined by Section 1607 A . Exception: Temporary structures complying with Section 3103.6.1.1. 1608 A .2 Ground snow loads. The ground snow loads to be used in determining the design snow loads for roofs shall be determined in accordance with the reliability-targeted (strength based) ground snow load values in Chapter 7 of ASCE 7 or Figures 1608 A .2(1) through 1608 A .2(4) for the contiguous United States. Site-specific case studies shall be determined in accordance with Chapter 7 of ASCE 7 and shall be approved by the building official.

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  • CBC § 1601A.1.2 Medium relevance — show source text

    centers.

    1601A.1.2 Amendments in this chapter. DSA-SS and OSHPD adopt this chapter and all amendments.

    Exception: Amendments adopted by only one agency appear in this chapter preceded with the appropriate acronym of the adopt- ing agency, as follows: 1. Division of the State Architect-Structural Safety:

    [DSA-SS] – For applications listed in Section 1.9.2.1. 2. Office of Statewide Hospital Planning and Development:

    [OSHPD 1] – For applications listed in Section 1.10.1.

    [OSHPD 4] – For applications listed in Section 1.10.4.

    1601A.2 Enforcement agency approval. In addition to the requirements of the California Administrative Code and the California Build- ing Code, any aspect of project design, construction, quality assurance or quality control programs for which this code requires approval by the Registered Design Professional (RDP), are also subject to approval by the enforcement agency.

    SECTION 1602 A —NOTATIONS

    1602 A .1 Notations. The following notations are used in this chapter:

    D = Dead load.

    D i = Weight of ice in accordance with Chapter 10 of ASCE 7.

    E = Combined effect of horizontal and vertical earthquake induced forces as defined in Section 12.4 of ASCE 7.

    F = Load due to fluids with well-defined pressures and maximum heights.

    F a = Flood load in accordance with Chapter 5 of ASCE 7.

    H = Load due to lateral earth pressures, ground water pressure or pressure of bulk materials.

    L = Live load.

    L r = Roof live load.

    p g(asd) = Allowable stress design ground snow load.

    p g = Ground snow load determined from Figures 1608.2(1) through 1608.2(4) and Table 1608.2.

    R = Rain load.

    S = Snow load.

    T = Cumulative effects of self-straining load forces and effects.

    V asd = Allowable stress design wind speed, mph (m/s) where applicable.

    V = Basic wind speed, V, mph (m/s) determined from Figures 1609 A .3(1) through 1609 A .3(4) or ASCE 7.

    V T = Tornado speed, mph (m/s) determined from Chapter 32 of ASCE 7.

    W = Load due to wind pressure.

    W i = Wind-on-ice in accordance with Chapter 10 of ASCE 7.

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    SECTION 1603 A —CONSTRUCTION DOCUMENTS

    1603 A .1 General. Construction documents shall show the material, size, section and relative locations of structural members with floor levels, column centers and offsets dimensioned. The design loads and other information pertinent to the structural design required by Sections 1603 A .1.1 through 1603 A .1.10 shall be indicated on the construction documents.

  • CBC § 3.1 Medium relevance — show source text

    Exception: Construction documents for buildings constructed in accordance with the conventional light-frame construction provisions of Section 2308 shall indicate the following structural design information:

    1. Floor and roof dead and live loads.

    2. Ground snow load, p g, and allowable stress design ground snow load, p g(asd) .

    3. Basic wind speed, V, mph (m/s), and allowable stress design wind speed, V asd , as determined in accordance with Section 1609 A .3.1 and wind exposure.

    4. Seismic design category and site class.

    5. Flood design data, if located in flood hazard areas established in Section 1612 A .3.

    6. Design load-bearing values of soils.

    7. Rain load data.

    [DSA-SS] Additional requirements are included in Section 4-210 and 4-317 of the California Administrative Code (Part 1, Title 24, C.C.R).

    [OSHPD 1] Additional requirements are included in Section 7-115 and 7-125 of the California Administrative Code.

    1603 A .1.1 Floor live load. The uniformly distributed, concentrated and impact floor live load used in the design shall be indicated for floor areas. Use of live load reduction in accordance with Section 1607 A .13 shall be indicated for each type of live load used in the design.

    1603 A .1.2 Roof live load. The roof live load used in the design shall be indicated for roof areas. 1603 A .1.3 Roof snow load data. The ground snow load, p g, shall be indicated. In areas where the ground snow load, p g , exceeds 15 pounds per square foot (psf) (0.72 kN/m [2] ), the following additional information shall also be provided, regardless of whether snow loads govern the design of the roof:

    1. Flat-roof snow load, p f .
    2. Snow exposure factor, C e .
    3. Risk category.
    4. Thermal factor, C t .
    5. Slope factor(s), C s .
    6. Drift surcharge load(s), p d , where the sum of p d and p f exceeds 30 psf (1.44 kN/m [2] ) .
    7. Width of snow drift(s), w .
    8. Winter wind parameter for snow drift, W 2 .

    1603 A .1.4 Wind and tornado design data. The following information related to wind loads and, where required by Section 1609 A .5, tornado loads shall be shown, regardless of whether wind or tornado loads govern the design of the lateral force-resisting system of the structure:

    1. Basic wind speed, V, mph (m/s), tornado speed, V T, mph (m/s), and allowable stress design wind speed, V asd, mph (m/s), as determined in accordance with Section 1609 A .3.1.
  • CBC § 16A-23 Medium relevance — show source text

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    1608 A .2.1 Ground snow conversion. Where required, the ground snow loads, p g, of Figures 1608 A .2(1) through 1608 A .2(4) and Table 1608 A .2 shall be converted to allowable stress design ground snow loads, p g(asd), using Equation 16 A -17. Equation 16 A -17 p g(asd) = 0.7 p g

    where:

    p g(asd) = Allowable stress design ground snow load. p g = Ground snow load determined from Figures 1608 A .2(1) through 1608 A .2(4) and Table 1608 A .2. 1608 A .3 Ponding instability. Ponding instability on roofs shall be evaluated in accordance with ASCE 7.

    1608A.4 Determination of snow loads. [DSA-SS] The ground snow load or the design snow load for roofs shall conform with the adopted ordinance of the city, county, or city and county in which the project site is located, and shall be approved by DSA. See Section 106.1.2 for snow load posting requirements.

    SECTION 1609 A —WIND LOADS

    1609 A .1 Applications. Buildings, structures and parts thereof shall be designed to withstand the minimum wind loads prescribed herein. Decreases in wind loads shall not be made for the effect of shielding by other structures.

    1609 A .1.1 Determination of wind loads. Wind loads on every building or structure shall be determined in accordance with Chapters 26 to 30 of ASCE 7. The type of opening protection required, the basic wind speed, V, and the exposure category for a site is permitted to be determined in accordance with Section 1609 A or ASCE 7. Wind shall be assumed to come from any horizontal direction and wind pressures shall be assumed to act normal to the surface considered.

    Exceptions:

    1. Subject to the limitations of Section 1609 A .1.1.1, the provisions of ICC 600 shall be permitted for applicable Group R-2 and R-3 buildings.

    2. Subject to the limitations of Section 1609 A .1.1.1, residential structures using the provisions of AWC WFCM.

    3. Subject to the limitations of Section 1609 A .1.1.1, residential structures using the provisions of AISI S230.

    4. Designs using NAAMM FP 1001.

    5. Designs using TIA-222 for antenna-supporting structures and antennas, provided that the horizontal extent of Topographic Category 2 escarpments in Section 2.6.6.2 of TIA-222 shall be 16 times the height of the escarpment.

    6. Wind tunnel tests in accordance with ASCE 49 and Sections 31.4 and 31.7 of ASCE 7.

    7. Temporary structures complying with Section 3103.6.1.2.

  • CBC § 0.00143 Medium relevance — show source text
    1. Linear interpolation is permitted between contours. Point values are provided to aid with interpolation.
    2. Islands, coastal areas and land boundaries outside the last contour shall use the last wind speed contour.
    3. Location-specific basic wind speeds shall be permitted to be determined using the ASCE Wind Design Geodatabase.
    4. Wind speeds for Hawaii, US Virgin Islands and Puerto Rico shall be determined from the ASCE Wind Design Geodatabase.
    5. Mountainous terrain, gorges, ocean promontories and special wind regions shall be examined for unusual wind conditions. Site specific values for selected special wind regions shall be permitted to be determined using the ASCE Wind Design Geodatabase.
    6. Wind speeds correspond to approximately a 7-percent probability of exceedance in 50 years (Annual Exceedance Probability = 0.00143, MRI = 700 years). 8. The ASCE Wind Design Geodatabase can be accessed at the ASCE 7 Hazard Tool (https://asce7hazardtool.online) or approved equivalent.

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    BUILDING PLANNING

    FIGURE R301.2(3)—ALLOWABLE STRESS DESIGN GROUND SNOW LOADS, P g (asd ) , FOR THE UNITED STATES (lb/ft [2] )

    For SI:1 foot = 34.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile = 1.61 km.

    Notes:

    1. Location-specific ground snow load values are provided in the Ground Snow Load Geodatabase of geocoded design ground snow load values, which can be accessed at the

    ASCE 7 Hazard Tool at https://asce7hazardtool.online/ or an approved equivalent. 2. Lines shown on the figure are contours separated by a constant ratio 1.18 with values of 10, 12, 14, 16, 19, 23, 27, 32, 38, 44, 52, 62, 73, 86, 101, 119 and 140 psf. 3. Values denoted with a “+” symbol indicate design ground snow loads at state capitals or other high-population locations. 4. Areas shown in gray represent areas with ground snow loads exceeding 140 psf. Ground snow load values for these locations can be determined from the Geodatabase. R301.2.1 Wind design criteria. Buildings and portions thereof shall be constructed in accordance with the wind provisions of this code using the ultimate design wind speed in Table R301.2 as determined from Figure R301.2(2). The structural provisions of this code for wind loads are not permitted where wind design is required as specified in Section R301.2.1.1. Where different construc-tion methods and structural materials are used for various portions of a building, the applicable requirements of this section for each portion shall apply. Where not otherwise specified, the wind loads listed in Table R301.2.1(1) adjusted for height and expo-sure using Table R301.2.1(2) shall be used to determine design load performance requirements for wall coverings, curtain walls, roof coverings, exterior windows, skylights, garage doors and exterior doors.

  • CBC § 2.2.8 Medium relevance — show source text

    R301.2.2.8 Cold-formed steel framing in Seismic Design Categories D 0 , D 1 and D 2 . In Seismic Design Categories D 0, D 1 and D 2 in addition to the requirements of this code, cold-formed steel framing shall comply with the requirements of AISI S230.

    R301.2.2.9 Masonry chimneys. In Seismic Design Categories D 0, D 1 and D 2, masonry chimneys shall be reinforced and anchored to the building in accordance with Sections R1003.3 and R1003.4.

    R301.2.2.10 Seismic restraint of appliances and equipment. In Seismic Design Categories D 0, D 1 and D 2 and in townhouses in Seismic Design Category C, appliances and equipment that are designed to be fixed in position shall be supported and braced or anchored to the structure in accordance with the component manufacturer’s recommendations or per Section R301.2.2.10.1.

    Exceptions: Seismic support, bracing and anchorage are not required for the following:

    1. Suspended mechanical ducts, electrical conduit, automatic sprinkler systems and plumbing systems.
    2. Where the appliance or equipment is bearing on an elevated floor or roof and the housing height is not greater than 1.5 times the width of the housing base in either direction.
    3. Where the installed weight of a suspended appliance or equipment is 50 pounds (22.7 kg) or less.
    4. Where the installed weight is 400 pounds (181.4 kg) or less and the bottom of the appliance or equipment is 4 feet (1219 mm) or less above the adjacent floor level.

    R301.2.2.10.1 Seismic restraint resistance. Supports, bracing and anchorage of appliances and equipment in Seismic Design Categories D 0, D 1 and D 2, and in townhouses in Seismic Design Category C, shall resist a horizontal force equal to onethird times the operating weight of the component, acting in any direction. Bracing shall comply with the following:

    1. Components supported at the base shall be braced with strapping at points within the upper one-third of the component’s vertical dimensions, or the component anchorage shall be designed to resist overturning.
    2. Components suspended from the structure shall be braced to the structure using either flexible or rigid bracing. Flexible bracing such as wires or straps shall be provided in each of the four orthogonal directions. Rigid bracing such as struts or bars may be provided in two orthogonal directions.

    R301.2.3 Snow loads. Ground snow loads shall be determined in accordance with Figure R301.2(3) or shall be determined in accordance in with Section 1608 of the California Building Code . Wood-framed construction, cold-formed, steel-framed construction and masonry and concrete construction, and structural insulated panel construction in regions with allowable stress design ground snow loads, p g(asd ), 70 pounds per square foot (3.35 kPa) or less, shall be in accordance with Chapters 5, 6 and 8. Buildings in regions with allowable stress design ground snow loads, p g(asd), greater than 70 pounds per square foot (3.35 kPa) shall be designed in accordance with accepted engineering practice.

  • CBC § 304.8 Medium relevance — show source text

    For locations in Anchorage/Eagle River and Homer above the cited elevation, the ground snow load shall be increased by 15 percent for every 100 feet above the cited
    elevation.|For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kN/m2.
    a. Statutory requirements of the building official are not included in this state ground snow load table.
    b. For locations where there is substantial change in altitude over the city/town, the load applies at and below the cited elevation within the jurisdiction and up to 100 feet
    above the cited elevation unless otherwise noted.
    c. For locations in Anchorage/Eagle River and Homer above the cited elevation, the ground snow load shall be increased by 15 percent for every 100 feet above the cited
    elevation.|

    1608.2.1 Ground snow conversion. Where required, the ground snow loads, p g, of Figures 1608.2(1) through 1608.2(4) and Table 1608.2 shall be converted to allowable stress design ground snow loads, p g(asd), using Equation 16-17. Equation 16-17 p g(asd) = 0.7 p g

    where:

    p g(asd) = Allowable stress design ground snow load. p g = Ground snow load determined from Figures 1608.2(1) through 1608.2(4) and Table 1608.2. 1608.3 Ponding instability. Ponding instability on roofs shall be evaluated in accordance with ASCE 7.

    2025 CALIFORNIA BUILDING CODE 16-19

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    STRUCTURAL DESIGN

    16-20 2025 CALIFORNIA BUILDING CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    STRUCTURAL DESIGN

    2025 CALIFORNIA BUILDING CODE 16-21

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    STRUCTURAL DESIGN

    16-22 2025 CALIFORNIA BUILDING CODE

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    STRUCTURAL DESIGN

    2025 CALIFORNIA BUILDING CODE 16-23

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    STRUCTURAL DESIGN

    SECTION 1609—WIND LOADS

    1609.1 Applications. Buildings, structures and parts thereof shall be designed to withstand the minimum wind loads prescribed herein. Decreases in wind loads shall not be made for the effect of shielding by other structures.

    1609.1.1 Determination of wind loads. Wind loads on every building or structure shall be determined in accordance with Chapters 26 to 30 of ASCE 7. The type of opening protection required, the basic wind speed, V, and the exposure category for a site is permitted to be determined in accordance with Section 1609 or ASCE 7. Wind shall be assumed to come from any horizontal direction and wind pressures shall be assumed to act normal to the surface considered.

Frequently asked questions

Where do I read off p_g for my exact address — the CBC figures or ASCE 7?

The CBC allows using the CBC figures (1608.2 figures) or the reliability‑targeted values in Chapter 7 of ASCE 7; for site‑specific or high‑precision needs you should use ASCE 7 procedures or the ASCE hazard geodatabases referenced by ASCE 7 as permitted by § 1608.2.

Do I always have to convert p_g to p_g(asd)?

No — convert only when an allowable‑stress design (ASD) ground snow load is required by your design method. When ASD values are required, § 1608.2.1 requires p_g(asd) = 0.7·p_g.

What if my site isn’t clearly on the CBC figure contours?

§ 1608.2 permits use of ASCE 7 Chapter 7 methods and site‑specific case studies; such cases must follow ASCE 7 and be approved by the building official.

Are there any shorthand reductions for temporary structures?

Yes — temporary public‑occupancy structures have specific ground‑snow reduction factors in § 3103.6.1.1, which modifies the p_g from § 1608.

Does Hawaii always get zero snow load?

Yes by default: § 1608.2 states snow loads are zero for Hawaii except for mountainous regions as approved by the building official.

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