CEBC · California Existing Building Code
When can elements be restored to predamage condition (less-than-substantial damage)?
If the damage does not meet the CEBC’s definition of “substantial structural damage,” you can usually repair and return the damaged elements to how they were before the event under § 405.2.1. Special cases — notably snow-related damage — are governed by § 405.2.1.1 and CBC § 1608, and damage that does meet the substantial thresholds requires a registered design professional evaluation and possible retrofit instead of simple restoration.
Last reviewed: July 6, 2026
What the code requires — plain English
- § 405.2.1 says that when a building has suffered damage that is less than substantial structural damage, the damaged elements are generally permitted to be restored to their predamage condition.
- § 405.2.1.1 adds that structural components damaged by snow must be repaired, replaced or altered to meet the snow-load rules in CBC § 1608 (so “restore to predamage” does not override applicable CBC snow requirements).
The single most important rule: If the damage does not meet the code’s definition of substantial structural damage, you may generally repair and restore the damaged elements back to their predamage condition under § 405.2.1.
Requirements in detail
Core rule
- Damaged elements are permitted to be restored to their predamage condition when the damage is less than substantial structural damage — in other words, repairs may return the element to its previous state rather than triggering a larger evaluation/retrofit requirement. § 405.2.1 is the controlling provision.
What “substantial structural damage” means (where the line is drawn)
- The CEBC gives numeric thresholds in the Chapter 2 definitions for Substantial Structural Damage (see § 202). These thresholds identify when damage is large enough to require evaluation and possible retrofit rather than simple restoration. Typical thresholds in the definitions include reductions in capacity such as vertical lateral system capacity reduced by more than 33%, or gravity components supporting large tributary areas reduced beyond specified percent limits (see § 202 definitions).
Related evaluation and retrofit triggers
- If damage meets the substantial-structural-damage definition, the building must be evaluated by a registered design professional and may require repair plus retrofit per § 405.2.3.1–405.2.3.3; only if that evaluation shows the predamage condition already complies with applicable load provisions may damaged elements be simply restored.
Snow-damage special rule
- Snow-related damage to structural components is a special case: those components shall be repaired, replaced or altered to satisfy CBC § 1608 (see § 405.2.1.1). Restoring to predamage condition is allowed only if the repair meets the CBC snow-load requirements referenced.
Decision-relevant dimensions (quick reference table)
| Decision dimension | Key values/thresholds | What it controls | Code Reference |
|---|---|---|---|
| Damage classification | Less than substantial structural damage = repair allowed to predamage condition | Permits restoration to predamage condition | § 405.2.1 |
| Snow-caused damage | Must meet CBC § 1608 snow-load requirements | Repairs / replacements must comply with CBC snow rules | § 405.2.1.1 |
| Substantial-structural threshold (definition) | Vertical lateral capacity reduced > 33% (typical CEBC definition language) — other numeric triggers for gravity/snow components also apply | If met → evaluation and likely retrofit required | § 202 (definitions) |
| Evaluation trigger | Building with substantial structural damage | Requires RDP evaluation per § 405.2.3.1 | § 405.2.3.1 |
| When repair-only allowed after eval | Evaluation shows predamage condition complies with CBC loads | Damaged elements may be restored to predamage condition | § 405.2.3.2 |
What “restore to predamage condition” typically means
- Reconstruct, replace or renew the damaged parts so they function and perform as they did before the damage (subject to exceptions below). New pieces used for that repair should meet applicable detailing for new members where the code requires it.
Exceptions & special cases
- Snow damage: Repairs caused by or related to snow loads are governed by CBC § 1608 and § 405.2.1.1; you cannot rely solely on § 405.2.1 if CBC snow requirements apply.
- Seismic concerns / disproportionate earthquake damage: Buildings in high seismic design categories (SDC D, E or F) with disproportionate earthquake damage are treated under the substantial-damage rules even if other thresholds might suggest otherwise (see § 405.2.2 and § 405.2.3).
- One- and two-family dwellings and some lower-risk SD categories: the code includes limited exceptions regarding evaluations/retrofits for certain dwellings and for damage not caused by earthquake in lower SDCs — consult § 405.2 exceptions.
- Where evaluation shows predamage condition noncompliant: If an RDP’s evaluation determines that restoring to predamage condition would leave the lateral system noncompliant with CBC load combinations, retrofit work is required rather than simple restoration (see § 405.2.3.3).
Common mistakes
- Assuming all repairs can be returned to the exact pre-damage materials/methods without checking thresholds — if damage meets the substantial structural damage definition you must follow the evaluation/retrofit path (don’t stop at § 405.2.1).
- Overlooking snow rules: repairing a roof member “to predamage” without verifying CBC § 1608 compliance for snow loads is a frequent error. § 405.2.1.1 explicitly points to CBC § 1608.
- Failing to obtain an evaluation when required: when thresholds are met, the code mandates an evaluation by a registered design professional (see § 405.2.3.1). Do not substitute an informal judgment.
- Ignoring RDP findings: if the evaluation shows the predamage condition is noncompliant, the owner must retrofit per § 405.2.3.3 — restoration-only is not permitted.
Worked example
Scenario: A two-story nonresidential building in SDC C suffers earthquake damage. An inspection shows the lateral force-resisting vertical elements for one story have lost 25% of lateral capacity compared to predamage. Chapter 2 defines substantial structural damage as vertical elements reduced by more than 33% (typical CEBC threshold). Because the observed reduction (25%) is less than the 33% substantial-damage threshold, the damage is less than substantial structural damage and the owner may, subject to other rules, restore the damaged elements to their predamage condition under § 405.2.1. However, because the damage was earthquake-related and the building is in SDC C, confirm there are no local or seismic disproportionate-damage provisions that change the outcome and check CBC load compliance; if in doubt or if any other thresholds are met, obtain an RDP evaluation per § 405.2.3.1.
Related provisions (CEBC sections)
- § 405.2 — Repairs to damaged buildings (general)
- § 405.2.1 — Repairs for less than substantial structural damage (restore to predamage)
- § 405.2.1.1 — Snow damage (requires CBC § 1608 compliance)
- § 405.2.2 — Disproportionate earthquake damage (special treatment for high SDCs)
- § 405.2.3 / § 405.2.3.1–.3 — Evaluation and extent of repair/retrofit when there is substantial structural damage
- § 202 — Definitions (including Substantial Structural Damage) — see numeric thresholds used to decide repair vs. retrofit
- CBC § 1608 — Snow-load requirements (referenced by § 405.2.1.1)
If you want, I can:
- Extract the exact § 202 definition language and its numeric thresholds as they appear in your edition, or
- Walk through a second worked example (snow-caused roof damage) applying CBC § 1608 and CEBC § 405.2.1.1 step-by-step.
Code references
Grounded in the retrieved California Existing Building Code — click a citation to read the verbatim passage:
CEBC § 405.2.1 High relevance — show source text
[BS] 405.2.1 Repairs for less than substantial structural damage. Unless otherwise required by this section, for damage less than substantial structural damage, the damaged elements shall be permitted to be restored to their predamage condition.
[BS] 405.2.1.1 Snow damage. Structural components whose damage was caused by or related to snow load effects shall be repaired, replaced or altered to satisfy the requirements of Section 1608 of the California Building Code .
[BS] 405.2.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.
[BS] 405.2.3 Substantial structural damage to vertical elements of the lateral force-resisting system. A building that has sustained substantial structural damage to the vertical elements of its lateral force-resisting system shall be evaluated in accordance with Section 405.2.3.1, and either repaired in accordance with Section 405.2.3.2 or repaired and retrofitted in accordance with Section 405.2.3.3, depending on the results of the evaluation.
Exceptions:
- Buildings assigned to Seismic Design Category A, B or C whose substantial structural damage was not caused by earthquake need not be evaluated or retrofitted for load combinations that include earthquake effects.
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- One- and two-family dwellings need not be evaluated or retrofitted for load combinations that include earthquake effects.
[BS] 405.2.3.1 Evaluation. The building shall be evaluated by a registered design professional, and the evaluation findings shall be submitted to the code official. The evaluation shall establish whether the lateral force-resisting system of the damaged building, including its foundation, if repaired to its predamage state, would comply with the provisions of the California Build- ing Code for load combinations that include wind effects, and with Section 304.3.2 of this code.
[BS] 405.2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
[BS] 405.2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The seismic retrofit shall comply with Section 304.3.2 of this code, but the earthquake loads shall not be less than those required by the building code in effect at the time of original construction.
CEBC § 105.2 High relevance — show source text
Exception: Routine maintenance required by Chapter 3A, ordinary repairs exempt from permit in accordance with California Building Code Section 105.2, and abatement of wear due to normal service conditions shall not be subject to the requirements for repairs in this section.
405 A .1.1 Structural concrete. Repair of structural concrete shall be permitted to comply with ACI 562 Section 1.7, except where Section 405.2.2, 405.2.3 or 405.2.4.1 requires compliance with Section 304.3.
405 A .2 Repairs to damaged buildings. Repairs to damaged buildings shall comply with this section.
405 A .2.1 Repairs for less than substantial structural damage. Unless otherwise required by this section, for damage less than substantial structural damage, the damaged elements shall be permitted to be restored to their predamage condition. New struc- tural members and connections used for this repair shall comply with the detailing provisions of this code for new buildings of similar structure, purpose and location.
405 A .2.1.1 Snow damage. Structural components whose damage was caused by or related to snow load effects shall be repaired, replaced or altered to satisfy the requirements of Section 1608 of the California Building Code .
405 A .2.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.
405 A .2.3 Substantial structural damage to vertical elements of the lateral force-resisting system. A building that has sustained substantial structural damage to the vertical elements of its lateral force-resisting system shall be evaluated in accordance with Section 405 A .2.3.1, and either repaired in accordance with Section 405 A .2.3.2 or repaired and retrofitted in accordance with Section 405 A .2.3.3, depending on the results of the evaluation.
405 A .2.3.1 Evaluation. The building shall be evaluated by a registered design professional, and the evaluation findings shall be submitted to the building official. The evaluation shall establish whether the lateral force-resisting system of the damaged building, including its foundation, if repaired to its predamage state, would comply with the provisions of the California Build- ing Code for load combinations that include wind and earthquake effects. Earthquake loads for this evaluation, if required, shall
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CEBC § 105.2 High relevance — show source text
401 A .2 Compliance. The work shall not make the building less complying than it was before the repair was undertaken. Work on nondamaged components that is necessary for the required repair of damaged components shall be considered part of the repair and shall not be subject to requirements for alterations.
401 A .3 Flood hazard areas. In flood hazard areas, repairs that constitute substantial improvement shall require that the building comply with Section 1612 A of the California Building Code .
SECTION 402 A —BUILDING ELEMENTS AND MATERIALS
402 A .1 Glass replacement. The installation or replacement of glass shall be as required for new installations in accordance with the California Building Code.
SECTION 403 A —FIRE PROTECTION
403 A .1 General. Fire protection shall comply with the California Building Standards Code.
SECTION 404 A —MEANS OF EGRESS
404 A .1 General. Repairs shall be done in a manner that maintains the level of protection provided for the means of egress.
SECTION 405 A —STRUCTURAL
405 A .1 General. Structural damage shall be repaired in compliance with this section and Section 401 A .2.
Exception: Routine maintenance required by Chapter 3A, ordinary repairs exempt from permit in accordance with California Building Code Section 105.2, and abatement of wear due to normal service conditions shall not be subject to the requirements for repairs in this section.
405 A .1.1 Structural concrete. Repair of structural concrete shall be permitted to comply with ACI 562 Section 1.7, except where Section 405.2.2, 405.2.3 or 405.2.4.1 requires compliance with Section 304.3.
405 A .2 Repairs to damaged buildings. Repairs to damaged buildings shall comply with this section.
405 A .2.1 Repairs for less than substantial structural damage. Unless otherwise required by this section, for damage less than substantial structural damage, the damaged elements shall be permitted to be restored to their predamage condition. New struc- tural members and connections used for this repair shall comply with the detailing provisions of this code for new buildings of similar structure, purpose and location.
405 A .2.1.1 Snow damage. Structural components whose damage was caused by or related to snow load effects shall be repaired, replaced or altered to satisfy the requirements of Section 1608 of the California Building Code .
405 A .2.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.
CEBC § 405.2.3.1 High relevance — show source text
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- One- and two-family dwellings need not be evaluated or retrofitted for load combinations that include earthquake effects.
[BS] 405.2.3.1 Evaluation. The building shall be evaluated by a registered design professional, and the evaluation findings shall be submitted to the code official. The evaluation shall establish whether the lateral force-resisting system of the damaged building, including its foundation, if repaired to its predamage state, would comply with the provisions of the California Build- ing Code for load combinations that include wind effects, and with Section 304.3.2 of this code.
[BS] 405.2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
[BS] 405.2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The seismic retrofit shall comply with Section 304.3.2 of this code, but the earthquake loads shall not be less than those required by the building code in effect at the time of original construction.
[BS] 405.2.4 Substantial structural damage to gravity load-carrying components. Gravity load-carrying components that have sustained substantial structural damage shall be retrofitted to comply with the applicable provisions for dead, live and snow loads in the California Building Code . Undamaged gravity load-carrying components, including undamaged foundation components, that receive dead, live or snow loads from retrofitted components shall also be retrofitted if required to comply with these design loads.
[BS] 405.2.4.1 Lateral force-resisting elements. Regardless of the level of damage to vertical elements of the lateral forceresisting system, if substantial structural damage to gravity load-carrying components was caused primarily by wind or seismic effects, then the building shall be evaluated in accordance with Section 405.2.3.1 and, if noncompliant, retrofitted in accordance with Section 405.2.3.3.
Exceptions:
- Buildings assigned to Seismic Design Category A, B or C whose substantial structural damage was not caused by earthquake need not be evaluated or retrofitted for load combinations that include earthquake effects.
- One- and two-family dwellings need not be evaluated or retrofitted for load combinations that include earthquake effects.
[BS] 405.2.5 Substantial structural damage to snow load-carrying components. Where substantial structural damage to any snow load-carrying components is caused by or related to snow load effects, any components required to carry snow loads on roof framing of similar construction shall be repaired, replaced or retrofitted to satisfy the requirements of Section 1608 of the California Building Code .
CEBC § 2-6 High relevance — show source text
For purposes of this definition, work done to implement repairs shall not be considered damage that reduces structural capacity.
SUBSTANTIAL STRUCTURAL DAMAGE. [OSHPD 1 & 1R] A condition where any of the following apply: 1. The vertical elements of the lateral force-resisting system have suffered damage such that the lateral load carrying capacity of any story in any horizontal direction has been reduced by more than 10 percent from its predamage condition. 2. The capacity of any vertical component carrying gravity load, or any group of such components, has a tributary area more than 15 percent of the total area of the structure’s floor(s) and roof(s), has been reduced more than 10 percent from its predamage condition, and the remaining capacity of such affected elements, with respect to all dead and live loads, is less than 75 percent of that required by the California Building Code for new buildings of similar structure, purpose and location. 3. The capacity of any structural component carrying snow load, or any group of such components, that supports more than 15 percent of the roof area of similar construction, has been reduced more than 10 percent from its predamage condition, and the
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DEFINITIONS
remaining capacity with respect to dead, live and snow loads is less than 75 percent of that required by the California Building Code for new buildings of similar structure, purpose and location.
TECHNICALLY INFEASIBLE. An alteration of a facility that has little likelihood of being accomplished because the existing structural conditions require the removal or alteration of a load-bearing member that is an essential part of the structural frame, or because other existing physical or site constraints prohibit modification or addition of elements, spaces or features which are in full and strict compliance with the minimum requirements for new construction and which are necessary to provide accessibility.
UNREINFORCED CONCRETE. [OSHPD 1, 1R, 2, 4 & 5] Unreinforced concrete as used in this chapter means plain concrete as defined in ACI 318 Section 2.3.
UNREINFORCED MASONRY. [OSHPD 1, 1R, 2, 4 & 5] Unreinforced masonry as used in this chapter means masonry construction where reinforcements in any direction is less than minimum reinforcement specified in TMS 402 Section 7.3.2.6.
UNSAFE. Buildings, structures or equipment that are unsanitary, or that are deficient due to inadequate means of egress facilities, inadequate light and ventilation, or that constitute a fire hazard, or in which the structure or individual structural members meet the definition of “Dangerous,” or that are otherwise dangerous to human life or the public welfare, or that involve illegal or improper occupancy or inadequate maintenance shall be deemed unsafe. A vacant structure that is not secured against entry shall be deemed unsafe.
[HCD 1 & HCD 2] An unsafe building, as defined in this chapter, shall be considered substandard.
CEBC § 401.3 High relevance — show source text
[BS] 401.3 Flood hazard areas. In flood hazard areas, repairs that constitute substantial improvement shall require that the building comply with Section 1612 of the California Building Code, or Section R306 of the California Residential Code, as applicable.
SECTION 402—BUILDING ELEMENTS AND MATERIALS
402.1 Glazing in hazardous locations. Replacement glazing in hazardous locations shall comply with the safety glazing requirements of the California Building Code or California Residential Code as applicable.
Exception: Glass block walls, louvered windows and jalousies repaired with like materials.
402.2 Existing materials. [HCD] Existing materials shall comply with Section 302.3.
402.3 New and replacement materials. [HCD & HCD 2] New and replacement materials used for repairs shall comply with Section 302.4.
SECTION 403—FIRE PROTECTION
403.1 General. Repairs shall be done in a manner that maintains the level of fire protection provided.
SECTION 404—MEANS OF EGRESS
404.1 General. Repairs shall be done in a manner that maintains the level of protection provided for the means of egress.
SECTION 405—STRUCTURAL
[BS] 405.1 General. Structural damage shall be repaired in compliance with this section and Section 401.2.
405.1.1 Structural concrete. Repair of structural concrete shall be permitted to comply with ACI 562 Section 1.7, except where Section 405.2.2, 405.2.3 or 405.2.4.1 requires compliance with Section 304.3.
[BS] 405.2 Repairs to damaged buildings. Repairs to damaged buildings shall comply with this section.
[BS] 405.2.1 Repairs for less than substantial structural damage. Unless otherwise required by this section, for damage less than substantial structural damage, the damaged elements shall be permitted to be restored to their predamage condition.
[BS] 405.2.1.1 Snow damage. Structural components whose damage was caused by or related to snow load effects shall be repaired, replaced or altered to satisfy the requirements of Section 1608 of the California Building Code .
[BS] 405.2.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.
[BS] 405.2.3 Substantial structural damage to vertical elements of the lateral force-resisting system. A building that has sustained substantial structural damage to the vertical elements of its lateral force-resisting system shall be evaluated in accordance with Section 405.2.3.1, and either repaired in accordance with Section 405.2.3.2 or repaired and retrofitted in accordance with Section 405.2.3.3, depending on the results of the evaluation.
Exceptions:
- Buildings assigned to Seismic Design Category A, B or C whose substantial structural damage was not caused by earthquake need not be evaluated or retrofitted for load combinations that include earthquake effects.
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CEBC § 2-6 High relevance — show source text
If the structure has sustained substantial damage, any repairs are considered substantial improvement regardless of the actual repair work performed. The term does not, however, include either of the following:
- Any project for improvement of a building required to correct existing health, sanitary or safety code violations identified by the code official and that is the minimum necessary to ensure safe living conditions.
- Any alteration of a historic structure, provided that the alteration will not preclude the structure’s continued designation as a historic structure.
[BS] SUBSTANTIAL STRUCTURAL ALTERATION. An alteration in which the gravity load-carrying structural elements altered within a 5-year period support more than 30 percent of the total floor and roof area of the building or structure. The areas to be counted toward the 30 percent shall include mezzanines, penthouses, and in-filled courts and shafts tributary to the altered structural elements.
[BS] SUBSTANTIAL STRUCTURAL DAMAGE. A condition where any of the following apply:
- The vertical elements of the lateral force-resisting system have suffered damage such that the lateral load-carrying capacity of any story in any horizontal direction has been reduced by more than 33 percent from its predamage condition.
- The capacity of any vertical component carrying gravity load, or any group of such components, that has a tributary area more than 30 percent of the total area of the structure’s floor(s) and roof(s) has been reduced more than 20 percent from its predamage condition, and the remaining capacity of such affected elements, with respect to all dead and live loads, is less than 75 percent of that required by the California Building Code for new buildings of similar structure, purpose and location.
- The capacity of any structural component carrying snow load, or any group of such components, that supports more than 30 percent of the roof area of similar construction has been reduced more than 20 percent from its predamage condition, and the remaining capacity with respect to dead, live and snow loads is less than 75 percent of that required by the Califor- nia Building Code for new buildings of similar structure, purpose and location.
For purposes of this definition, work done to implement repairs shall not be considered damage that reduces structural capacity.
SUBSTANTIAL STRUCTURAL DAMAGE. [OSHPD 1 & 1R] A condition where any of the following apply: 1. The vertical elements of the lateral force-resisting system have suffered damage such that the lateral load carrying capacity of any story in any horizontal direction has been reduced by more than 10 percent from its predamage condition. 2. The capacity of any vertical component carrying gravity load, or any group of such components, has a tributary area more than 15 percent of the total area of the structure’s floor(s) and roof(s), has been reduced more than 10 percent from its predamage condition, and the remaining capacity of such affected elements, with respect to all dead and live loads, is less than 75 percent of that required by the California Building Code for new buildings of similar structure, purpose and location. 3. The capacity of any structural component carrying snow load, or any group of such components, that supports more than 15 percent of the roof area of similar construction, has been reduced more than 10 percent from its predamage condition, and the
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DEFINITIONS
CEBC § 3.4. High relevance — show source text
[BS] ROOF COATING. A fluid-applied adhered coating used for roof maintenance, roof repair or as a component of a roof covering system or roof assembly.
[BS] ROOF RECOVER. The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering.
[BS] ROOF REPAIR. Reconstruction or renewal of any part of an existing roof for the purpose of correcting damage or restoring the predamage condition.
[BS] ROOF REPLACEMENT. The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.
SPC SEISMIC SEPARATION. [OSHPD 1 & 1R] Means a building separation in accordance with the California Administrative Code, Chap- ter 6 Section 3.4.
SUBSTANDARD BUILDING. [HCD 1, HCD 2] See Health and Safety Code Section 17920.3.
[BG] STORM SHELTER. A building, structure or portions thereof, constructed in accordance with ICC 500, designated for use during hurricanes, tornadoes or other severe windstorms.
[BS] SUBSTANTIAL DAMAGE. For the purpose of determining compliance with the flood provisions of this code, damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.
[BS] SUBSTANTIAL IMPROVEMENT. For the purpose of determining compliance with the flood provisions of this code, any repair, alteration, addition or improvement of a building or structure, the cost of which equals or exceeds 50 percent of the market value of the structure, before the improvement or repair is started. If the structure has sustained substantial damage, any repairs are considered substantial improvement regardless of the actual repair work performed. The term does not, however, include either of the following:
- Any project for improvement of a building required to correct existing health, sanitary or safety code violations identified by the code official and that is the minimum necessary to ensure safe living conditions.
- Any alteration of a historic structure, provided that the alteration will not preclude the structure’s continued designation as a historic structure.
[BS] SUBSTANTIAL STRUCTURAL ALTERATION. An alteration in which the gravity load-carrying structural elements altered within a 5-year period support more than 30 percent of the total floor and roof area of the building or structure. The areas to be counted toward the 30 percent shall include mezzanines, penthouses, and in-filled courts and shafts tributary to the altered structural elements.
[BS] SUBSTANTIAL STRUCTURAL DAMAGE. A condition where any of the following apply:
- The vertical elements of the lateral force-resisting system have suffered damage such that the lateral load-carrying capacity of any story in any horizontal direction has been reduced by more than 33 percent from its predamage condition.
- The capacity of any vertical component carrying gravity load, or any group of such components, that has a tributary area more than 30 percent of the total area of the structure’s floor(s) and roof(s) has been reduced more than 20 percent from its predamage condition, and the remaining capacity of such affected elements, with respect to all dead and live loads, is less than 75 percent of that required by the California Building Code for new buildings of similar structure, purpose and location.
CEBC § 2.3.2 High relevance — show source text
405 A .2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
405 A .2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The earthquake loads shall not be less than those required by the building code in effect at the time of original construction but not less than 75 percent of those prescribed in California Building Code Section 1613A. Alternatively, where the earthquake damage has not resulted in disproportionate earthquake damage or did not result in collapse, the retrofit shall be permitted to be performed in accordance with Section 304A.3.4.4 for SPC-2 buildings, Section 304A.3.4.5 for SPC-3, SPC-4D and SPC-4 buildings and Section 304A.3.4.6 for SPC-5 buildings. For SPC-5 buildings, the seismic hazard shall be permitted to be reduced to BSE-1E and BSE-2E. Use of Section 304A.3.4.5 to rehabilitate SPC-3, SPC-4D and SPC-4 buildings will result in re-classification of the building to SPC-4D. Noncompliant SPC-4 buildings may be rehabilitated to SPC-5 in accordance with Section 304A.3.4.6 using the reduced seismic hazard. New structural members and connections required by this rehabilitation design shall comply with the detailing provisions of this code for new buildings of similar structure, purpose and location.
405 A .2.4 Substantial structural damage to gravity load-carrying components. Gravity load-carrying components that have sustained substantial structural damage shall be retrofitted to comply with the applicable provisions for dead, live and snow loads in the California Building Code . Undamaged gravity load-carrying components, including undamaged foundation components, that receive dead, live or snow loads from retrofitted components shall also be retrofitted if required to comply with these design loads. New structural members and connections required by this rehabilitation design shall comply with the detailing provi- sions of this code for new buildings of similar structure, purpose and location.
405 A .2.4.1 Lateral force-resisting elements. Regardless of the level of damage to vertical elements of the lateral force-resisting system, if substantial structural damage to gravity load-carrying components was caused primarily by wind or seismic effects, then the building shall be evaluated in accordance with Section 405 A .2.3.1 and, if noncompliant, retrofitted in accordance with Section 405 A .2.3.3.
Exceptions:
CEBC § 2.2 High relevance — show source text
405 A .2.2 Disproportionate earthquake damage. A building assigned to Seismic Design Category D, E or F that has sustained disproportionate earthquake damage shall be subject to the requirements for buildings with substantial structural damage to vertical elements of the lateral force-resisting system.
405 A .2.3 Substantial structural damage to vertical elements of the lateral force-resisting system. A building that has sustained substantial structural damage to the vertical elements of its lateral force-resisting system shall be evaluated in accordance with Section 405 A .2.3.1, and either repaired in accordance with Section 405 A .2.3.2 or repaired and retrofitted in accordance with Section 405 A .2.3.3, depending on the results of the evaluation.
405 A .2.3.1 Evaluation. The building shall be evaluated by a registered design professional, and the evaluation findings shall be submitted to the building official. The evaluation shall establish whether the lateral force-resisting system of the damaged building, including its foundation, if repaired to its predamage state, would comply with the provisions of the California Build- ing Code for load combinations that include wind and earthquake effects. Earthquake loads for this evaluation, if required, shall
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REPAIRS
be permitted to be 75 percent of those prescribed in California Building Code Section 1613A. Alternatively, where the earthquake damage has not resulted in disproportionate earthquake damage or did not result in collapse, the earthquake load evaluation shall be permitted to be performed in accordance with Section 304A.3.4.4 for SPC-2 buildings and Section 304A.3.4.5 for buildings rated SPC-3, SPC-4D and SPC-4. SPC-5 buildings shall be permitted to be evaluated in accordance with Section 304A.3.4.6, except that the seismic hazard shall be permitted to be reduced to BSE-1E and BSE-2E.
405 A .2.3.2 Extent of repair for compliant buildings. If the evaluation establishes that the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the damaged elements shall be permitted to be restored to their predamage condition.
405 A .2.3.3 Extent of repair for noncompliant buildings. If the evaluation does not establish that the lateral force-resisting system of the building in its predamage condition complies with the provisions of Section 405.2.3.1, then the lateral forceresisting system, and its foundation, shall be retrofitted to comply with the provisions of this section. The wind loads for the repair and retrofit shall be those required by the building code in effect at the time of original construction, unless the damage was caused by wind, in which case the wind loads shall be in accordance with the California Building Code . The earthquake loads shall not be less than those required by the building code in effect at the time of original construction but not less than 75 _percent of those prescribed in California Building Code Section 1613A.
CEBC § 2-5 Medium relevance — show source text
[A] REGISTERED DESIGN PROFESSIONAL IN RESPONSIBLE CHARGE. A registered design professional engaged by the owner or the owner’s authorized agent to review and coordinate certain aspects of the project, as determined by the code official, for compatibility with the design of the building or structure, including submittal documents prepared by others, deferred submittal documents and phased submittal documents.
[A] RELOCATABLE BUILDING. A partially or completely assembled building constructed and designed to be reused multiple times and transported to different building sites.
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DEFINITIONS
[A] REPAIR. The reconstruction, replacement or renewal of any part of an existing building for the purpose of its maintenance or to correct damage.
REPAIR. [OSHPD 1] as used in this Code means all the design and construction work affecting existing or requiring new structural elements undertaken to restore or enhance the structural and nonstructural load-resisting system participating in vertical or lateral response of a structure primarily intended to correct the effects of deterioration or impending or actual failure, regardless of cause.
[BS] REROOFING. The process of recovering or replacing an existing roof covering. See “ Roof recover ” and “ Roof replacement .”
[BS] RISK CATEGORY. A categorization of buildings and other structures for determination of flood, wind, snow, ice and earthquake loads based on the risk associated with unacceptable performance, as provided in Section 1604.5 of the California Building Code .
[BS] ROOF COATING. A fluid-applied adhered coating used for roof maintenance, roof repair or as a component of a roof covering system or roof assembly.
[BS] ROOF RECOVER. The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering.
[BS] ROOF REPAIR. Reconstruction or renewal of any part of an existing roof for the purpose of correcting damage or restoring the predamage condition.
[BS] ROOF REPLACEMENT. The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.
SPC SEISMIC SEPARATION. [OSHPD 1 & 1R] Means a building separation in accordance with the California Administrative Code, Chap- ter 6 Section 3.4.
SUBSTANDARD BUILDING. [HCD 1, HCD 2] See Health and Safety Code Section 17920.3.
[BG] STORM SHELTER. A building, structure or portions thereof, constructed in accordance with ICC 500, designated for use during hurricanes, tornadoes or other severe windstorms.
[BS] SUBSTANTIAL DAMAGE. For the purpose of determining compliance with the flood provisions of this code, damage of any origin sustained by a structure whereby the cost of restoring the structure to its before-damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.
[BS] **SUBSTANTIAL IMPROVEMENT.
CEBC § 2-50 Medium relevance — show source text
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[BF] RESPONSIVE VAPOR RETARDER. A vapor retarder material complying with a vapor retarder class of Class I or II, but that also has a vapor permeance of 1 perm or greater in accordance with ASTM E96, water method (Procedure B).
[BE] RESTRICTED ENTRANCE. An entrance that is made available for common use on a controlled basis, but not public use, and that is not a service entrance.
[BG] RETRACTABLE AWNING. A retractable awning is a cover with a frame that retracts against a building or other structure to which it is entirely supported.
RETROFIT. [DSA-SS, DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] The construction of any new element or system, or the alteration of any existing element or system required to bring an existing building, or portion thereof, conforming to earlier code requirements, into conformance with standards of the currently effective California Building Standards Code.
RISER. The upright part between two adjacent stair treads, between either an upper or lower landing and an adjacent stair tread, or between two adjacent landings.
[BS] RISK CATEGORY. A categorization of buildings and other structures for determination of flood, wind, snow, ice and earthquake loads based on the risk associated with unacceptable performance.
[BS] ROOF ASSEMBLY (For application to Chapter 15 only). A system designed to provide weather protection and resistance to design loads. The system consists of a roof covering and roof deck or a single component serving as both the roof covering and the roof deck. A roof assembly can include an underlayment, a thermal barrier, insulation or a vapor retarder.
[BS] ROOF COATING. A fluid-applied, adhered coating used for roof maintenance or roof repair, or as a component of a roof covering system or roof assembly.
[BS] ROOF COVERING. The covering applied to the roof deck for weather resistance, fire classification or appearance.
ROOF COVERING SYSTEM. See “Roof assembly.”
[BS] ROOF DECK. The flat or sloped surface constructed on top of the exterior walls of a building or other supports for the purpose of enclosing the story below, or sheltering an area, to protect it from the elements, not including its supporting members or vertical supports.
ROOF DRAINAGE, POSITIVE. See “Positive roof drainage.”
[BS] ROOF RECOVER. The process of installing an additional roof covering over a prepared existing roof covering without removing the existing roof covering.
[BS] ROOF REPAIR. Reconstruction or renewal of any part of an existing roof for the purposes of correcting damage or restoring predamage condition.
[BS] ROOF REPLACEMENT. The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.
[BG] ROOF VENTILATION. The natural or mechanical process of supplying conditioned or unconditioned air to, or removing such air from, attics, cathedral ceilings or other enclosed spaces over which a roof assembly is installed.
Frequently asked questions
When is a registered design professional required?
When damage meets the code’s substantial structural damage thresholds or when § 405.2.3.1 requires an evaluation (for example, substantial damage to vertical elements), a registered design professional must evaluate the building and submit findings to the code official.
Can I always use identical materials to restore an element to predamage condition?
Generally yes for less-than-substantial damage under § 405.2.1, but if the repair affects seismic/wind/snow performance or the RDP/code official requires upgraded detailing, you must comply. Snow damage must meet CBC § 1608 per § 405.2.1.1.
What if the predamage condition was already noncompliant with current CBC loads?
If restoring to predamage condition would leave the building noncompliant for required load combinations, the building will likely need retrofit work rather than simple restoration — see § 405.2.3.3.
Does “restore to predamage condition” trigger permits or other procedural steps?
Repairs may still require permits or inspections per local permitting rules and the California Building Code; routine maintenance and some ordinary repairs are exempt, but substantial repairs/improvements and work requiring evaluation/retrofit will involve formal submittals. Check the local jurisdiction and see CEBC repair/permit cross-references.
If snow caused the damage but the original roof was under-designed for current CBC snow loads, can I just reinstall what was there?
No — § 405.2.1.1 requires snow-related repairs to satisfy CBC § 1608; you must ensure the repaired components meet the applicable snow-load requirements.
More in California Existing Building Code
- Administration and Definitions (Scope, enforcement, code official duties, definitions)
- Provisions for All Compliance Methods (general requirements that apply to all compliance options; Chapter 3 / 3A)
- Seismic retrofit and evaluation (Appendix A and seismic provisions/sections for evaluation and retrofit)
- Referenced Standards and Appendices (Chapter 16 and Appendices A–E, Resource A)
- Repairs (Chapter 4 — repair-specific rules for materials, means of egress, structural, MEP, etc.)
- Alterations — Level 1, Level 2, Level 3 (technical requirements for each alteration level; Chapters 7–9)
- Change of Occupancy and Additions (requirements for occupancy changes and additions; Chapters 10–11)
- Compliance Methods — Prescriptive, Work Area, Performance (Chapters 5, 6–11, 13)
- Relocated Buildings (requirements for buildings moved or relocated; Chapter 14)
- Construction Safeguards (site safety, means of egress and life-safety during construction; Chapter 15)
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