CRC · California Residential Code

What are the required design criteria and loads (dead, live, snow, wind, seismic)?

Q: What is the single controlling sentence in the CRC about loads?

The controlling obligation is in § R301.1 : buildings must be constructed to safely support dead, live, roof, flood, snow, wind and seismic loads and provide a complete load path to the foundation.

The CRC requires that every residential building be designed to carry all applicable loads — **dead, live, snow, wind and seismic** — and to provide a continuous load path to the foundation (see **§ R301.1**). Alternative prescriptive standards (AWC WFCM, AISI S230, ICC 400) are allowed within limits under **§ R301.1.1**. Use the specific CRC span/tables for member dead/live assumptions and follow the referenced building-code/ASCE load-combination rules for final design.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

Buildings and structures must be built to safely support dead loads, live loads, roof/snow loads, wind loads, seismic loads (and other applicable loads) and provide a complete load path from the point of origin to the foundation — this is the core requirement of § R301.1.
As an alternative to the prescriptive provisions, certain recognized prescriptive standards (for example AWC WFCM, AISI S230, ICC 400) are permitted if used within their limitations; these are allowed by § R301.1.1.

The single most important rule: a building complying with the code must be able to transfer all required loads (dead, live, snow, wind, seismic, etc.) through a continuous load path to the foundation. § R301.1

Requirements in detail

1) Scope and basic obligation

The code requires that all parts of the building be “constructed to safely support” the listed loads and that a complete load path be provided. See § R301.1.
If a designer elects to use one of the permitted alternative prescriptive standards, that option and its limits are in § R301.1.1.

2) What “loads” are expected to be considered (plain English)

Dead loads = the self-weight of structural elements and permanently attached materials (structure + fixed finishes). (See the general requirement in § R301.1.)
Live loads = occupiable, movable loads such as people, furniture, maintenance loads; these are shown in design tables and used in combinations.
Snow loads = site-specific and slope/exposure dependent; CRC provides conversion tables (e.g., wind-to-snow equivalency tables) and references for snow-load calculation where applicable.
Wind loads = determined per CRC tables that reference wind-speed/exposure (see referenced CRC wind tables).
Seismic loads = seismic design parameters and categories are applied per referenced design standards; the CRC allows alternative prescriptive standards but seismic design still must be provided.

3) Typical decision‑relevant values (examples taken from CRC design-assumption tables)

Load or criterion	Typical CRC value (example / table entry)	Code reference
Roof dead load (example)	10 psf (CRC design-assumption entries)	See CRC design-assumption tables in Chapter tables — example values shown in CRC tables.
Roof/ceiling dead load (alternative table)	12 psf (appears in CRC framing/roof tables)	CRC framing/roof tables (example entry).
Maximum roof live load (table example)	70 psf (shown as a maximum in specific CRC tables)	CRC span/design tables.
Ceiling dead load (table example)	5 psf	CRC span/design tables.
Ceiling live load (table example)	20 psf	CRC span/design tables.
Second-floor live load (common residential design value)	30 psf	CRC member/header tables and design assumptions.
Deflection criteria	L/240 (for many roof/ceiling live-load deflection checks; some tables use L/360 for floors)	CRC span & framing tables (design assumptions).
Wind-to-snow equivalency (conversion)	Tabulated values by wind speed, exposure, roof slope (see table)	TABLE R804.3.2.1 in CRC.

Notes:

The CRC publishes many table-based “design assumptions” used for sizing/members and span tables; the values above are examples pulled from CRC tables and headers — always confirm which specific table applies to your member and location.
Where tables differ (e.g., 10 psf vs 12 psf roof dead load), the governing table for your detail and material must be used — see the specific table header and notes.

4) How loads are combined

The CRC itself establishes the obligation to design for the listed loads (dead, live, snow, wind, seismic) in § R301.1; load combinations and equations are provided in the referenced structural design provisions (the California Building Code and ASCE 7 references govern the strength/combinational rules used in practice). For how loads are combined (e.g., D + L + 0.6W; D + L + 0.7S + E/1.4, etc.), see the CBC load-combination equations and exceptions.

Exceptions & special cases

Alternative prescriptive standards (AWC WFCM, AISI S230, ICC 400) may be used in place of the CRC prescriptive provisions if used within their stated limitations; when such engineered design is used in conjunction with those standards, it must comply with the California Building Code. See § R301.1.1.
Some CRC tables include different assumed dead/live values depending on the specific member, roof slope, snow zone or framing detail — always read the table notes and headings; examples of differing assumptions appear across CRC span tables.
Where snow or seismic conditions are significant, additional site-specific parameters (ground snow load pg, exposure factors, spectral seismic parameters, site class, etc.) must be determined per the referenced standards and shown on the construction documents. The CRC references these requirements and permits use of alternative prescriptive standards under § R301.1.1.

Common mistakes

Relying on a single generic number for roof or floor loads without checking the exact CRC table and its footnotes (different tables and details use different assumption values). Always cite the specific CRC table being used for that member.
Forgetting to provide a continuous load path for lateral and vertical loads — § R301.1 requires transfer of loads from point of origin to foundation; missing connectors, improper anchorage, or interrupted load paths are frequent errors.
Using an alternative prescriptive standard outside its permitted scope — if you use AWC WFCM or AISI S230, ensure the limitations in § R301.1.1 are followed and that any engineered elements also comply with the CBC where required.
Not showing design loads or required parameters on the construction documents — while CRC requires the safe support of loads (R301.1), the referenced building-code provisions require that design loads and seismic/wind/snow data be shown on the drawings (see related code references).

Worked example — one-story simple roof area (numbers from CRC example tables)

Scenario: A one‑story residential roof, plan area = 1,000 ft², use CRC design-assumption values from the CRC span/roof tables as an example: roof dead load = 10 psf, roof live load = 20 psf (use appropriate table values for your detail).

Determine area loads (uniform):
- Dead load D = 10 psf × 1,000 ft² = 10,000 lb.
- Live load L = 20 psf × 1,000 ft² = 20,000 lb.
Total unfactored load = D + L = 30,000 lb.
Example strength load-combination (per CBC/ASCE-derived combinations used in practice):
- Wind-controlled combo: D + L + 0.6W (if W governs lateral loads). For illustration, if design wind pressure W acting on the roof corresponds to 5 psf net upward pressure, W × area = 5 psf × 1,000 ft² = 5,000 lb → D + L + 0.6W = 10,000 + 20,000 + 0.6×5,000 = 43,000 lb. (See CBC load combinations for exact factors and governing combinations.) cite
Seismic-combination consideration (if seismic governs): follow the applicable CBC/ASCE load-combination (e.g., D + L + 0.7S + E/1.4, or D + L + 0.7S + E/1.4 depending on method). Always use the exact combination required by the governing design standard; CBC contains those equations and exceptions.

Note: The numbers above are illustrative examples taken from CRC table entries and CBC combination rules; your actual design must use the specific CRC table that applies to the member and the site-specific wind/snow/seismic parameters.

Related provisions (CRC sections)

§ R301 — Design Criteria (chapter heading and context for R301.1)
§ R301.1 — Application: requirement to support dead, live, roof, flood, snow, wind, seismic loads and provide a complete load path.
§ R301.1.1 — Alternative provisions permitted (AWC WFCM, AISI S230, ICC 400) and limitations.
§ R804.3.2.1 / TABLE R804.3.2.1 — Wind-to-snow conversion tables and associated roof-slope/exposure tables (used where tables apply).
Example CRC span/header tables (e.g., Table R603.6(4) and other CRC framing tables) — contain the example dead/live values and deflection criteria referenced in CRC design-assumption notes.

(For load‑combination equations and detailed combination rules used in practice, the California Building Code references and ASCE 7 provide the formal combinations — see the CBC provisions as the implementing reference.)

Code references

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

CRC § 2.1 High relevance — show source text

Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
CRC § 2.1 High relevance — show source text

Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
CRC § 2.1 High relevance — show source text
447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.

CRC § 0.447 High relevance — show source text

0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.
DR = Design Required.
a.
Design assumptions:
Maximum deflection criteria: L/240.
Maximum roof dead load: 10 psf.
Maximum roof live load: 70 psf.
Maximum ceiling dead load: 5 psf.
Maximum ceiling live load: 20 psf.
Wind loads based on Table R301.2.1(1).
Strength axis of facing material applied vertically.|

TABLE R610.5(2)—MINIMUM THICKNESS FOR SIP WALL SUPPORTING SIP OR LIGHT-FRAME ONE STORY AND ROOF ONLY (inches)a	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12	Col13	Col14	Col15	Col16	Col17	Col18
BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)	BUILDING WIDTH (ft)
ULTIMATE DESIGN WIND SPEEDV ult (mph)	ULTIMATE DESIGN WIND SPEEDV ult (mph)	GROUND **SNOW

CRC § 1604.8.3 High relevance — show source text
See Sections 1609 for wind design requirements and 1613 for earthquake design requirements. 1604.8.3 Decks. Where supported by attachment to an exterior wall, decks shall be positively anchored to the primary structure and designed for both vertical and lateral loads as applicable. Such attachment shall not be accomplished by the use of toenails or nails subject to withdrawal. Where positive connection to the primary building structure cannot be verified during inspection, decks shall be self-supporting. Connections of decks with cantilevered framing members to exterior walls or other framing members shall be designed for both of the following:
1. The reactions resulting from the dead load and live load specified in Table 1607.1, or the snow load specified in Section 1608, in accordance with Section 1605, acting on all portions of the deck.
2. The reactions resulting from the dead load and live load specified in Table 1607.1, or the snow load specified in Section 1608, in accordance with Section 1605, acting on the cantilevered portion of the deck, and no live load or snow load on the remaining portion of the deck. 1604.9 Wind and seismic detailing. Lateral force-resisting systems shall meet seismic detailing requirements and limitations prescribed in this code and ASCE 7 Chapters 11, 12, 13, 15, 17 and 18 as applicable, even where wind load effects are greater than seismic load effects.
Exception: References within ASCE 7 to Chapter 14 shall not apply, except as specifically required herein.

1604.10 Loads on storm shelters. Loads and load combinations on storm shelters shall be determined in accordance with ICC 500.

SECTION 1605—LOAD COMBINATIONS

1605.1 General. Buildings and other structures and portions thereof shall be designed to resist the strength load combinations specified in ASCE 7, Section 2.3, the allowable stress design load combinations specified in ASCE 7, Section 2.4, or the alternative allowable stress design load combinations of Section 1605.2.

Exceptions:
1. The modifications to load combinations of ASCE 7, Section 2.3, ASCE 7, Section 2.4 and Section 1605.2 specified in ASCE 7 Chapters 18 and 19 shall apply.
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STRUCTURAL DESIGN
1. Where the allowable stress design load combinations of ASCE 7, Section 2.4 are used, flat roof snow loads of 45 pounds per square foot (2.15 kN/m [2] ) and roof live loads of 30 pounds per square foot (1.44 kN/m [2] ) or less need not be combined with seismic load. Where flat roof snow loads exceed 45 pounds per square foot (2.15 kN/m [2] ), 15 percent shall be combined with seismic loads.
2. Where the allowable stress design load combinations of ASCE 7 Section 2.4 are used, crane hook loads need not be combined with roof live loads or with more than three-fourths of the snow load or one-half of the wind loads.
3. Where design for tornado loads is required, the alternative allowable stress design load combinations of Section 1605.2 shall not apply when tornado loads govern the design.
CRC § 16A-9 High relevance — show source text
1. The reactions resulting from the dead load and live load specified in Table 1607 A .1, or the snow load specified in Section 1608 A, in accordance with Section 1605 A, acting on the cantilevered portion of the deck, and no live load or snow load on the remaining portion of the deck. 1604 A .9 Wind and seismic detailing. Lateral force-resisting systems shall meet seismic detailing requirements and limitations prescribed in this code and ASCE 7 Chapters 11, 12, 13, 15, 17 and 18 as applicable, even where wind load effects are greater than seismic load effects.
Exception: References within ASCE 7 to Chapter 14 shall not apply, except as specifically required herein.

1604 A .10 Loads on storm shelters. Loads and load combinations on storm shelters shall be determined in accordance with ICC 500.

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STRUCTURAL DESIGN

SECTION 1605 A —LOAD COMBINATIONS

1605 A .1 General. Buildings and other structures and portions thereof shall be designed to resist the strength load combinations specified in ASCE 7, Section 2.3, the allowable stress design load combinations specified in ASCE 7, Section 2.4, or the alternative allowable stress design load combinations of Section 1605 A .2. Exceptions:
1. The modifications to load combinations of ASCE 7, Section 2.3, ASCE 7, Section 2.4 and Section 1605 A .2 specified in ASCE 7 Chapters 18 and 19 shall apply.
2. Where the allowable stress design load combinations of ASCE 7, Section 2.4 are used, flat roof snow loads of 45 pounds per square foot (2.15 kN/m [2] ) and roof live loads of 30 pounds per square foot (1.44 kN/m [2] ) or less need not be combined with seismic load. Where flat roof snow loads exceed 45 pounds per square foot (2.15 kN/m [2] ), 15 percent shall be combined with seismic loads.
3. Where the allowable stress design load combinations of ASCE 7 Section 2.4 are used, crane hook loads need not be combined with roof live loads or with more than three-fourths of the snow load or one-half of the wind loads.
4. Where design for tornado loads is required, the alternative allowable stress design load combinations of Section 1605 A .2 shall not apply when tornado loads govern the design.
CRC § 3.1 High 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.

CRC § 25.4 High relevance — show source text

Deflection criteria:L/240 for live loads and_L_/180 for total loads.
c. Roof dead load = 12 psf.
d. Grade 33 ksi steel is permitted to be used for 33 mil and 43 mil thicknesses. Grade 50 ksi steel shall be used for 54 and 68 mil thicknesses.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa.
a. Table provides maximum horizontal rafter spans in feet and inches for slopes between 3:12 and 12:12.
b. Deflection criteria:L/240 for live loads and_L_/180 for total loads.
c. Roof dead load = 12 psf.
d. Grade 33 ksi steel is permitted to be used for 33 mil and 43 mil thicknesses. Grade 50 ksi steel shall be used for 54 and 68 mil thicknesses.|

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ROOF-CEILING CONSTRUCTION

TABLE R804.3.2.1(2)—ULTIMATE DESIGN WIND SPEED TO EQUIVALENT SNOW LOAD CONVERSION	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12
ULTIMATE WIND SPEED AND EXPOSURE	ULTIMATE WIND SPEED AND EXPOSURE	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)
ULTIMATE WIND SPEED AND EXPOSURE	ULTIMATE WIND SPEED AND EXPOSURE	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope
Exposure	Wind speed (mph)	3:12	4:12	5:12	6:12	7:12	8:12	9:12	10:12	11:12	**

CRC § 3-3 High relevance — show source text
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Part III— Building Planning and Construction

3 BUILDING PLANNING

User notes:

About this chapter: Chapter 3 contains a wide array of building planning requirements that are critical to designing a safe and usable building. This includes, but is not limited to, requirements related to general structural design, fire-resistant construction, light, ventilation, sanitation, plumbing fixture clearances, minimum room area and ceiling height, safety glazing, means of egress, automatic fire sprinkler systems, smoke and carbon monoxide alarm systems, accessibility and solar energy systems.

SECTION R300—SITE DRAINAGE

R300.1 Storm water drainage and retention during construction. Projects which disturb less than one acre of soil and are not part of a larger common plan of development which in total disturbs one acre or more, shall manage storm water drainage during construction in accordance with the California Green Building Standards Code, Chapter 4, Division 4.1.

R300.2 Grading and paving. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings in accordance with the California Green Building Standards Code, Chapter 4, Division 4.1.

SECTION R301—DESIGN CRITERIA

R301.1 Application. Buildings and structures, and parts thereof, shall be constructed to safely support all loads, including dead loads, live loads, roof loads, flood loads, snow loads, wind loads and seismic loads as prescribed by this code. The construction of buildings and structures in accordance with the provisions of this code shall result in a system that provides a complete load path that meets the requirements for the transfer of loads from their point of origin through the load-resisting elements to the foundation. Buildings and structures constructed as prescribed by this code are deemed to comply with the requirements of this section.

Existing buildings housing existing protective social care homes or facilities established prior to 1972 (see Chapter 11 of the California Fire Code and the California Existing Building Code).

R301.1.1 Alternative provisions. As an alternative to the requirements in Section R301.1, the following standards are permitted subject to the limitations of this code and the limitations therein. Where engineered design is used in conjunction with these standards, the design shall comply with the California Building Code .
1. AWC Wood Frame Construction Manual (WFCM).
2. AISI Standard for Cold-Formed Steel Framing—Prescriptive Method for One- and Two-Family Dwellings (AISI S230).
3. ICC Standard on the Design and Construction of Log Structures (ICC 400).
R301.1.1.1 Alternative provisions for limited-density owner-built rural dwellings. The purpose of this subsection is to permit alternatives that provide minimum protection of life, limb, health, property, safety and welfare of the general public and the owners and occupants of limited-density owner-built rural dwellings as defined in Chapter 2 of this code. For additional informa- tion see Chapter 1, Subchapter 1, Article 8, of Title 25, California Code of Regulations, commencing with Section 74.
CRC § 1603.1 High relevance — show source text
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.

1603.1.2 Roof live load. The roof live load used in the design shall be indicated for roof areas. 1603.1.3 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 .
1603.1.4 Wind and tornado design data. The following information related to wind loads and, where required by Section 1609.5, 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 1609.3.1.
2. Risk category.
CRC § 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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STRUCTURAL DESIGN

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.
CRC § 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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STRUCTURAL DESIGN

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.

Frequently asked questions

What is the single controlling sentence in the CRC about loads?

The controlling obligation is in § R301.1: buildings must be constructed to safely support dead, live, roof, flood, snow, wind and seismic loads and provide a complete load path to the foundation.

May I use AWC WFCM or AISI S230 instead of the CRC prescriptive tables?

Yes — the CRC permits certain alternative prescriptive standards (AWC WFCM, AISI S230, ICC 400) subject to the code’s limitations; see § R301.1.1 for permitted alternatives and conditions.

Where do I find the numeric load values to use for a member?

Numeric values appear in CRC span and framing tables (examples cited earlier). Always use the specific table that applies to your member/detail and check the table notes — example table entries are shown in the CRC design-assumption tables.

Do I need to show loads and design parameters on the drawings?

Yes — the applicable construction-document requirements require showing design loads, snow/wind/seismic data and related items; those requirements are implemented in the building-code provisions that the CRC refers to for structural design. Consult the applicable code documentary sections.

If tables show different dead‑load values (10 psf vs 12 psf), which applies?

Use the table that governs the particular member/detail; table headers, footnotes and the specific chapter/table context determine which value applies. When in doubt, follow the table that directly addresses your material/type of construction.

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Related in the CRC

How must stormwater drainage and site grading be managed during construction?

When does flood‑resistant construction apply and what sections govern it?

Site & Design Criteria

California Residential Code

TABLE R804.3.2.1(2)—ULTIMATE DESIGN WIND SPEED TO EQUIVALENT SNOW LOAD CONVERSION	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12
ULTIMATE WIND SPEED AND EXPOSURE	ULTIMATE WIND SPEED AND EXPOSURE	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)	EQUIVALENT GROUND SNOW LOAD (psf)
ULTIMATE WIND SPEED AND EXPOSURE	ULTIMATE WIND SPEED AND EXPOSURE	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope	Roof slope
Exposure	Wind speed (mph)	3:12	4:12	5:12	6:12	7:12	8:12	9:12	10:12	11:12	**