CEBC · California Existing Building Code
How must a relocated building be connected to its foundation?
If your building is moved, CEBC **§1402.2.1** requires that its attachment to the foundation meet the California Building Code or California Residential Code anchorage rules. Appendix A gives specific guidance: anchor sill plates to continuous foundations with adhesive or expansion anchors (plate washer, nut tightened to snugtight), use alternative details only when they meet a **900‑lb** minimum shear capacity, replace or strengthen poor sills or foundations, and follow the CBC/CRC details for embedment and spacing.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
A relocated building must be anchored to its foundation in accordance with the regular California Building Code or the California Residential Code — the CEBC does not create a new anchorage method itself but requires compliance with those codes. See §1402.2.1 for the controlling statement that the connection “shall comply with the California Building Code or the California Residential Code, as applicable.”
The single most important rule: a relocated building’s connection to the foundation must meet the same anchorage standards required for new or altered buildings under the CBC or CRC (see §1402.2.1).
Requirements in detail
Primary obligation
- The CEBC requires the building’s foundation system to comply with the CBC or CRC and then specifically requires the building-to-foundation connection to comply with the CBC or CRC (CEBC §1402.2 and §1402.2.1).
What CEBC Appendix A (guidance for seismic retrofit) says about sill anchorage
When practical details are needed for anchoring moved buildings, CEBC Appendix A provides clear guidance for sill-plate anchorage and acceptable alternatives:
- All perimeter wall sill plates shall be anchored to an existing continuous perimeter foundation using adhesive or expansion anchors in accordance with §A304.3.1. The plate washer goes between the nut and the sill plate, and the nut is tightened to a snugtight condition (hand-wrench torque) after adhesive cures or expansion engagement.
- Where you cannot install anchors through the top of the sill, CEBC Appendix A permits specified alternative connections (see Figures A304.3.1(2)–(4)).
- Alternative connections must have a minimum shear capacity of 900 pounds per connection parallel to the wall (Appendix A).
- Expansion anchors must not be used where their installation causes surface cracking of the foundation wall.
Condition of foundations and sills
- If the moved building has structural weaknesses (for example, sill plates or floor framing supported directly on the ground, or noncontinuous perimeter foundations), a new perimeter foundation or evaluation/strengthening is required under Appendix A (see §A303.1 and §A304.2.1).
- Where new concrete foundations are provided, CEBC requires a minimum compressive strength of 2,500 psi for new concrete (Appendix A).
- Where new sill plates are installed, they must be at least two times nominal thickness and preservative-treated or naturally durable; fasteners in contact with treated wood must be corrosion-resistant as required by the building code (Appendix A).
Cross-reference to CBC/CRC detailing requirements
- Because §1402.2.1 directs compliance to the CBC/CRC, typical dimensional rules from the CRC/CBC (for example, anchor-bolt embedment depths and spacing schedules shown in the Residential Code figures and tables) apply where the Residential Code governs the structure. See the CRC anchorage detail language about anchor bolt embedment (e.g., 15 inches into masonry or 7 inches into concrete where shown in CRC detail notes) when CRC details are used.
Decision-relevant dimensions & values (quick reference)
| Requirement / value | Typical number or descriptor | Code Reference |
|---|---|---|
| Controlling CEBC directive for connection | Comply with CBC or CRC | §1402.2.1 — |
| Minimum shear capacity for alternative connection | 900 pounds per connection | §A304.3.1 — |
| Bolt size referenced for spacing table | 1/2‑inch (12.7 mm) bolts (used in Table A304.3.1 references) | §A304.3.1 — |
| Anchor embedment depth examples (CRC details) | 15 in into masonry; 7 in into concrete (CRC figure notes) | CRC anchorage details — |
| New concrete foundation compressive strength | 2,500 psi (28 days) | §A304.2.4 — |
| New sill plate thickness & treatment | Two times nominal thickness; preservative-treated or naturally durable | §A304.2.6 — |
| Tightening requirement for adhesive/expansion anchors | Tighten nut to snugtight after curing/engagement | §A304.3.1 (definition of snugtight also in CEBC) — |
Exceptions & special cases
- CEBC Chapter 14 itself does not create a separate exception for connection; it defers to the CBC/CRC. The CRC contains an appendix for relocated residential buildings (Appendix BO) that relaxes certain new-construction requirements provided specific safety conditions are met — but §1402.2.1 still requires the connection to meet the CBC or CRC anchorage rules where those codes apply.
- If the moved building is located where wind or seismic loads at the new site are not greater than at the prior site, some wind/seismic provisions in Chapter 14 have exceptions; however, the connection detail must still comply with CBC/CRC where applicable (see CEBC §1402.3 and §1402.4 exceptions). Use these exceptions only if the specific criteria are met.
- Where an existing foundation is partial or is unreinforced masonry, a registered design professional evaluation (or replacement/strengthening) is required before relying on that foundation for anchorage. §A304.2.2 addresses evaluation and strengthening.
Common mistakes
- Assuming “moved = temporary” and skipping code-required anchorage — CEBC §1402.2.1 explicitly requires compliance with the CBC/CRC anchorage rules.
- Installing expansion anchors where their installation cracks the foundation surface — Appendix A disallows expansion anchors when they cause cracking.
- Failing to tighten adhesive anchors only after cure, or tightening them beyond a snugtight condition contrary to Appendix A instructions (snugtight is a specific hand-wrench definition in CEBC).
- Not verifying the condition of existing sill plates and framing (rot, insect damage, or fungus) before anchoring — Appendix A requires sound wood or replacement.
- Using alternative anchorage without confirming the minimum 900‑lb shear capacity per connection or without following the spacing requirements of Table A304.3.1.
Worked example — concrete scenario using code numbers
Scenario: You move a one‑story wood-frame house onto an existing continuous concrete foundation. The job falls under CEBC Chapter 14 and Appendix A guidance; therefore anchorage must comply with the CBC/CRC per §1402.2.1.
What you check and specify:
- Use adhesive anchors installed through the sill plate into the foundation with a plate washer under the nut. Per CEBC Appendix A, the nut is tightened to snugtight after the adhesive cures. (§A304.3.1)
- If CRC anchor‑bolt embedment notes apply to this residential attachment detail, specify embedment consistent with CRC details (for example, the CRC figure notes show anchor bolts extending 7 inches into concrete or 15 inches into masonry where that detail is used). (CRC detail reference)
- If you cannot put anchors through the top of the sill, prepare an alternative detail from CEBC Appendix A Figures A304.3.1(2)–(4) and verify each alternative connector provides at least 900 pounds shear capacity parallel to the wall. (§A304.3.1)
- If you pour a new concrete perimeter foundation as part of the work, design that concrete to a minimum 2,500 psi (28‑day) per §A304.2.4.
This example shows the decision path and numerical targets you must meet; exact anchor spacing and bolt size are taken from the CBC/CRC details or Appendix A Table A304.3.1 where applicable.
Related provisions (CEBC sections)
- §1402.2 — Foundation system of relocated buildings shall comply with CBC or CRC.
- §1402.2.1 — Connection to the foundation shall comply with CBC or CRC (primary controlling section for this topic).
- §1402.3 — Wind loads (relocated building must comply with CBC/CRC wind provisions; exceptions for some dwellings).
- §1402.4 — Seismic loads (relocated building must comply with CBC/CRC seismic provisions; limited exceptions).
- §A303.1 — Lists structural weaknesses that trigger foundation or anchorage strengthening (Appendix A).
- §A304.2.1 — Requirement for new perimeter foundations when certain weaknesses exist (Appendix A).
- §A304.2.4 — Minimum compressive strength for new concrete foundations: 2,500 psi (Appendix A).
- §A304.2.6 — New sill plate material and treatment requirements (Appendix A).
- §A304.3.1 — Detailed sill plate anchorage provisions, anchor capacity (900 lb alt. connection), nut tightening and anchorage installation requirements (Appendix A).
- CEBC Appendix BO (Residential Code Appendix) — Conditions under which relocated residential buildings are permitted to avoid full new-construction compliance; still, §1402.2.1 governs the anchorage requirement through CBC/CRC.
Code references
Grounded in the retrieved California Existing Building Code — click a citation to read the verbatim passage:
CEBC § 1401.1.1 High relevance — show source text
and the California Code of Regulations, Title 25, Division 1, Chapter 2._ Manufactured homes must meet unit identification (data plate) and certification label requirements as specified in the Code of Federal Regulations, Title 24, Subtitle B, Chapter XX, Part 3280 and Health and Safety Code Section 18032. Commercial modulars and special purpose commercial modulars must meet identification requirements in the California Code of Regulations, Title 25, Division 1, Chapter 3, Subchapter 2.
1401.1.1 Bleachers, folding and telescopic seating and grandstands. Relocated or moved bleachers, folding and telescopic seating and grandstands shall comply with ICC 300.
1401.2 Conformance. The building shall be safe for human occupancy as determined by the California Fire Code and the Interna- tional Property Maintenance Code . Any repair, alteration or change of occupancy undertaken within the moved structure shall comply with the requirements of this code applicable to the work being performed. Any field-fabricated elements shall comply with the requirements of the California Building Code or the California Residential Code, as applicable. [HCD 1 & HCD 2] After July 1, 1978, local ordinances or regulations for relocated or moved apartment houses and dwellings shall permit the retention of existing materials and methods of construction, provided the apartment house or dwelling complies with the building standards for foundations applica- ble to new construction and does not become or continue to be a substandard building. For additional information, see Health and Safety Code Section 17958.9.
SECTION 1402—REQUIREMENTS
1402.1 Location on the lot. The building shall be located on the lot in accordance with the requirements of the California Building Code or the California Residential Code, as applicable.
[BS] 1402.2 Foundation. The foundation system of relocated buildings shall comply with the California Building Code or the Califor- nia Residential Code, as applicable.
[BS] 1402.2.1 Connection to the foundation. The connection of the relocated building to the foundation shall comply with the California Building Code or the California Residential Code, as applicable.
[BS] 1402.3 Wind loads. Buildings shall comply with California Building Code or California Residential Code wind provisions, as applicable.
Exceptions:
- Detached one- and two-family dwellings and Group U occupancies where wind loads at the new location are not higher than those at the previous location.
- Structural elements whose stress is not increased by more than 10 percent.
[BS] 1402.4 Seismic loads. Buildings shall comply with California Building Code or California Residential Code seismic provisions at the new location, as applicable.
Exceptions:
- Structures in Seismic Design Categories A and B and detached one- and two-family dwellings in Seismic Design Categories A, B and C where the seismic loads at the new location are not higher than those at the previous location.
- Structural elements whose stress is not increased by more than 10 percent.
[BS] 1402.5 Snow loads. Structures shall comply with California Building Code or California Residential Code snow loads, as applicable, where snow loads at the new location are higher than those at the previous location.
Exception: Structural elements whose stress is not increased by more than 5 percent.
CEBC § 1402.2 High relevance — show source text
[BS] 1402.2 Foundation. The foundation system of relocated buildings shall comply with the California Building Code or the Califor- nia Residential Code, as applicable.
[BS] 1402.2.1 Connection to the foundation. The connection of the relocated building to the foundation shall comply with the California Building Code or the California Residential Code, as applicable.
[BS] 1402.3 Wind loads. Buildings shall comply with California Building Code or California Residential Code wind provisions, as applicable.
Exceptions:
- Detached one- and two-family dwellings and Group U occupancies where wind loads at the new location are not higher than those at the previous location.
- Structural elements whose stress is not increased by more than 10 percent.
[BS] 1402.4 Seismic loads. Buildings shall comply with California Building Code or California Residential Code seismic provisions at the new location, as applicable.
Exceptions:
- Structures in Seismic Design Categories A and B and detached one- and two-family dwellings in Seismic Design Categories A, B and C where the seismic loads at the new location are not higher than those at the previous location.
- Structural elements whose stress is not increased by more than 10 percent.
[BS] 1402.5 Snow loads. Structures shall comply with California Building Code or California Residential Code snow loads, as applicable, where snow loads at the new location are higher than those at the previous location.
Exception: Structural elements whose stress is not increased by more than 5 percent.
[BS] 1402.6 Flood hazard areas. If relocated or moved into a flood hazard area, structures shall comply with Section 1612 of the California Building Code, or Section R306 of the California Residential Code, as applicable.
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RELOCATED OR MOVED BUILDINGS
[BS] 1402.7 Required inspection and repairs. The code official shall be authorized to inspect, or to require approved professionals to inspect at the expense of the owner, the various structural parts of a relocated building to verify that structural components and connections have not sustained structural damage. Any repairs required by the code official as a result of such inspection shall be made prior to the final approval.
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CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE
CHAPTER 15 – CONSTRUCTION SAFEGUARDS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC-
CGSFM HCD Col6 Col7 DSA Col9 Col10 OSHPD Col12 Col13 Col14 Col15 Col16 Col17 BSCC DPH AGR DWR CEC CA SL SLC Adopting CEBC § 3.1 High relevance — show source text
NR = Uplift connector not required.
d. Foundation anchor straps are permitted in place of anchor bolts, if spaced as required to provide equivalent anchorage to the required anchor bolts and installed in accor-
dance with manufacturer’s requirements.
e. See Figure R603.3.1(4) for details.|For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s, 1 foot = 304.8 mm, 1 pound = 4.45 N.
a. Anchor bolts are to be located not more than 12 inches from corners or the termination of bottom tracks, such as at door openings or corners. Bolts are to extend not less than
15 inches into masonry or 7 inches into concrete.
b. All screw sizes shown are minimum.
c. NR = Uplift connector not required.
d. Foundation anchor straps are permitted in place of anchor bolts, if spaced as required to provide equivalent anchorage to the required anchor bolts and installed in accor-
dance with manufacturer’s requirements.
e. See Figure R603.3.1(4) for details.|For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s, 1 foot = 304.8 mm, 1 pound = 4.45 N.
a. Anchor bolts are to be located not more than 12 inches from corners or the termination of bottom tracks, such as at door openings or corners. Bolts are to extend not less than
15 inches into masonry or 7 inches into concrete.
b. All screw sizes shown are minimum.
c. NR = Uplift connector not required.
d. Foundation anchor straps are permitted in place of anchor bolts, if spaced as required to provide equivalent anchorage to the required anchor bolts and installed in accor-
dance with manufacturer’s requirements.
e. See Figure R603.3.1(4) for details.|FIGURE R603.3.1(1)—WALL TO FLOOR CONNECTION
FLOOR JOIST
FLOOR SHEATHING
NO. 8 SCREWS SPACED PER TABLE R603.3.1
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WALL CONSTRUCTION
TRACK
For SI: 1 inch = 25.4 mm.
For SI: 1 mil = 0.0254 mm, 1 inch = 25.4 mm.
FIGURE R603.3.1(2)—WALL TO FOUNDATION CONNECTION
NO. 8 SCREW THROUGH EACH FLANGE
4 NO. 8 SCREWS THROUGH EACH FLANGE
STUD BLOCKING INSIDE WALL TRACK (MINIMUM THICKNESS OF STUD)
ANCHOR BOLT OR OTHER CONNECTION AS REQUIRED
FOUNDATION OR SLAB ON GRADE
SILL SEALER AS REQUIRED
FIGURE R603.3.1(3)—WALL TO WOOD SILL CONNECTION
MINIMUM 3 ″ x 4 ″ x 33 MIL
METAL PLATE
4-10d OR 6-8d COMMON NAIL
NO. 8 SCREW THROUGH EACH FLANGE
MINIMUM 4 NO. 8 SCREWS
ANCHOR BOLT THROUGH WOOD SILL OR OTHER CONNECTION AS REQUIRED
6-56 2025 CALIFORNIA RESIDENTIAL CODE
CEBC § 319.8. High relevance — show source text
unless it can be demonstrated that_ reduced capacity meets the requirements of Section 319.8. 2. The lateral loading to or strength requirement of existing structural components is not increased beyond their capacity. 3. New structural components are detailed and connected to the existing structural components as required by the California Building Code. 4. New or relocated nonstructural components are detailed and connected to existing or new structural components as required by the California Building Code. 5. A dangerous condition is not created.
Use of ASCE 41 Tier 1 and Tier 2 deficiency only retrofit procedures are pre-approved for use where Section 317.3 does not require an
assessment.
319.12.1 State-owned buildings. [BSC] Voluntary modifications to lateral force-resisting systems conducted in accordance with Appendix A of this code and the referenced standards of the California Building Code shall be permitted.
319.12.1.1 Design documents. [BSC] When Section 319.12 is the basis for structural modifications, the approved design documents must clearly state the scope of the seismic modifications and the accepted criteria for the design. The approved design documents must clearly have the phrase “The seismic requirements of the California Existing Building Code have not been checked to determine if these structural modifications meet the full seismic evaluation and strengthening requirements of Sections 317-322: the modifications proposed are to a different seismic performance standard than would be required in Section 319 if they were not voluntary as allowed in Section 319.12.”
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PROVISIONS FOR ALL COMPLIANCE METHODS
319.12.2 Public schools and community colleges. [DSA-SS, DSA-SS/CC] When Section 319.12 is the basis for structural modifications, the approved design documents must clearly indicate the scope of modifications and the acceptance criteria for the design.
SECTION 320 [BSC, DSA-SS & DSA-SS/CC]—METHOD A
320.1 General. The retrofit design shall employ the Linear Static or Linear Dynamic Procedures of ASCE 41, Section 7.4.1 or 7.4.2, and comply with the applicable general requirements of ASCE 41, Chapters 6 and 7. The earthquake hazard level and performance level given specified in Section 317.5 for the building’s risk category shall be used. Structures shall be designed for seismic forces coming from any horizontal direction.
SECTION 321 [BSC, DSA-SS & DSA-SS/CC]—METHOD B
321.1 The existing or retrofitted structure shall be demonstrated to have the capability to sustain the deformation response due to the specified earthquake ground motions and meet the seismic performance requirements of Section 317. The registered design professional shall provide an evaluation of the response of the existing structure in its modified configuration and condition to the ground motions specified. If the building’s seismic performance is evaluated as satisfactory and the peer reviewer(s) and the enforcement agency concurs, then no further structural retrofit and/or repair of the lateral load-resisting system is required.
CEBC § 1.3 High relevance — show source text
EXISTING STUD WALL WITH SOLE
EXISTING 2x BLOCKING
OR RIM JOIST WITH
EXISTING TOENAILS
SEE SECTION A304.1.3
EXISTING SILL PLATE
EXISTING GROUND LEVEL
EXISTING SHEATHING OVER
EXISTING FLOOR FRAMING
7″ x [3] / 16 ″ x 9″ LONG PLATE WITH TWO [1] / 2 ″ DIAMETER ADHESIVE ANCHORS OR EXPANSION ANCHORS TO FOUNDATION WALL AND THREE [1] / 4 ″ DIAMETER LAG SCREWS PREDRILLED INTO SILL PLATE. PROVIDE SINGLE PIECE WOOD STRUCTURAL PANEL SHIM OR MULTIPLE LAYERS OF WOOD STRUCTURAL PANEL BETWEEN PLATE AND SILL WHEN SPACING EXCEEDS [3] / 16 ″ AND IS LESS THAN OR EQUAL TO 1 [1] / 2 ″. SEE TABLE A304.3.1 FOR SPACING OF ANCHORS
1″-5″ MIN.
1 / 4 ″ DIAMETER LAG SCREW 2 [1] / 2 ″ MIN. INTO SILL PLATE FOR SHIM ATTACHMENT
¾″ Col2 Col3 1″ 9″ ¾″
1″HOLE DIAMETER SHALL NOT EXCEED CONNECTOR DIAMETER BY MORE THAN [1] / 16 ″
SINGLE PIECE SHIM (AS REQUIRED)
5 / 16 ″ DIAMETER HOLES FOR [1] / 4 ″ LAG SCREWS
7″ x 9″ PLATE
For SI: 1 inch = 25.4 mm. a. If shim space exceeds 1 [1] / 2 inches, alternative details will be required. b. Where required, single piece shim shall be naturally durable wood or preservative-treated wood. If preservative-treated wood is used, it shall be isolated from the foundation system with a moisture barrier.
[BS] FIGURE A304.3.1(3)—ALTERNATIVE SILL PLATE ANCHOR TO EXISTING
FOUNDATION WITHOUT CRIPPLE WALL AND FLOOR FRAMING PARALLEL TO FOUNDATIONS
FOR SHIMS, WHERE REQUIRED SEE NOTE B, FIGURE A304.3.1(2)
SEE FIGURE A304.3.1(2) FOR
For SI: 1 inch = 25.4 mm.
Col1 Col2 SEE FIGU
CONNECT
FOR SHIM
SEE NOTE2025 CALIFORNIA EXISTING BUILDING CODE APPENDIX A-37
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APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE A304.3.1(4)—SILL PLATE ANCHORING TO EXISTING FOUNDATION—ALTERNATIVE CONNECTION FOR BATTERED FOOTING
For SI: 1 inch = 25.4 mm.
CEBC § 3.1 High relevance — show source text
[BS] A303.1 General. For the purposes of this chapter, any of the following conditions shall be deemed a structural weakness:
- Sill plates or floor framing that are supported directly on the ground without a foundation system that conforms to the building code.
- A perimeter foundation system that is constructed only of wood posts supported on isolated pad footings.
- Perimeter foundation systems that are not continuous.
Exceptions:
- Existing single-story exterior walls not exceeding 10 feet (3048 mm) in length, forming an extension of floor area beyond the line of an existing continuous perimeter foundation.
- Porches, storage rooms and similar spaces not containing fuel-burning appliances.
- A perimeter foundation system that is constructed of unreinforced masonry or stone.
- Sill plates that are not connected to the foundation or that are connected with less than what is required by the building code.
Exception: Where approved by the code official, connections of a sill plate to the foundation made with other than sill bolts shall be accepted if the capacity of the connection is equivalent to that required by the building code. 6. Cripple walls that are not braced in accordance with the requirements of Section A304.4 and Table A304.3.1, or cripple walls not braced with diagonal sheathing or wood structural panels in accordance with the building code.
SECTION A304—STRENGTHENING REQUIREMENTS
[BS] A304.1 General.
[BS] A304.1.1 Scope. The structural weaknesses noted in Section A303 shall be strengthened in accordance with the requirements of this section. Strengthening work may include both new construction and alteration of existing construction. Except as provided herein, all strengthening work and materials shall comply with the applicable provisions of the California Building Code .
[BS] A304.1.2 Condition of existing wood materials. Existing wood materials that will be a part of the strengthening work (such as sills, studs and sheathing) shall be in a sound condition and free from defects that substantially reduce the capacity of the member. Any wood material found to contain fungus infection shall be removed and replaced with new material. Any wood material found to be infested with insects or to have been infested with insects shall be strengthened or replaced with new materials to provide a net dimension of sound wood equal to or greater than its undamaged original dimension.
[BS] A304.1.3 Floor joists not parallel to foundations. Floor joists framed perpendicular or at an angle to perimeter foundations shall be restrained either by an existing nominal 2-inch-wide (51 mm) continuous rim joist or by a nominal 2-inch-wide (51 mm) full-depth block between alternate joists in one- and two-story buildings, and between each joist in three-story buildings. Existing blocking for multiple-story buildings must occur at each joist space above a braced cripple wall panel.
Existing connections at the top and bottom edges of an existing rim joist or blocking need not be verified in one story buildings. In multiple-story buildings, the existing top edge connection need not be verified; however, the bottom edge connection to either the foundation sill plate or the top plate of a cripple wall shall be verified. The minimum existing bottom edge connection shall consist of 8d toenails spaced 6 inches (152 mm) apart for a continuous rim joist, or three 8d toenails per block. Where this minimum bottom edge-connection is not present or cannot be verified, a supplemental connection installed as shown in Figure A304.1.3 or A304.1.4(2) shall be provided.
CEBC § 1.1.3 Medium relevance — show source text
see Note 35.|N/A|2 hrs||1|||2| |W-6-M-55|61/2″|Core: hollow concrete units; see Notes 46, 51, 54;
facings: one side; see Note 35.|N/A|2 hrs
30 min||1|||21/2| |W-6-M-56|61/2″|Core: hollow concrete units; see Notes 46, 53, 54;
facings: one side; see Note 35.|N/A|4 hrs||1|||4| |W-6-M-57|61/2″|Core: hollow concrete units; see Notes 47, 53, 54;
facings: one side; see Note 35.|N/A|3 hrs||1|||3| |W-6-M-58|61/2″|Core: hollow concrete units; see Notes 47, 51, 54;
facings: one side; see Note 35.|N/A|2 hrs||1|||2| |W-6-M-59|61/2″|Core: hollow concrete units; see Notes 47, 50, 54;
facings: one side; see Note 35.|N/A|1 hr
45 min||1|||13/4| |W-7-M-60|7″|Core: hollow concrete units; see Notes 46, 53, 54;
facings: both sides; see Note 35.|N/A|5 hrs||1|||5| |W-7-M-61|7″|Core: hollow concrete units; see Notes 46, 51, 54;
facings: both sides; see Note 35.|N/A|3 hrs
30 min||1|||31/2| |W-7-M-62|7″|Core: hollow concrete units; see Notes 46, 50, 54;
facings: both sides; see Note 35.|N/A|2 hrs 30
min||1|||21/2| |W-7-M-63|7″|Core: hollow concrete units; see Notes 47, 53, 54;
facings: both sides; see Note 35.|N/A|4 hrs||1|||4| |W-7-M-64|7″|Core: hollow concrete units; see Notes 47, 51, 54;
facings: both sides; see Note 35.|N/A|2 hrs 30
min||1|||21/2| |W-7-M-65|7″|Core: hollow concrete units; see Notes 47, 50, 54;
facings: both sides; see Note 35.|N/A|2 hrs||1|||2| |W-6-M-66|6″|Concrete wall with 4″ × 4″ No. 6 wire fabric (welded)
near wall center for reinforcement.|300
psi|2 hrs 30
min|||43|2|21/2|2025 CALIFORNIA EXISTING BUILDING CODE RESOURCE A-31
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RESOURCE A—GUIDELINES ON FIRE RATINGS OF ARCHAIC MATERIALS AND ASSEMBLIES
TABLE 1.1.3—continued
CEBC § 4-10 Medium relevance — show source text
THICK WOOD STRUCTURAL NEW 2x BLOCKING WITH 4-10d PANEL. SEE FIGURE A304.4.1(3) FOR NAILS EACH BLOCK TO SILL. PANEL AND NAILING LAYOUT PRE-DRILLED HOLES AS NEEDED
TO PRECLUDE SPLITTING
For SI: 1 inch = 25.4 mm.
NOTES:
- See Section A304.3 for sill plate anchorage.
Col1 Col2 Col3 - See manufacturing instructions for nail sizes associated with metal framing clips.
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APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS
[BS] FIGURE A304.1.4(3)—ALTERNATIVE FLOOR FRAMING TO CRIPPLE WALL CONNECTION
EXISTING 2-2x OR 1-2x PLATE
NEW 2x BLOCK BETWEEN EACH
STUD WHEN EXISTING CRIPPLE
STUD WALL HAS SINGLE TOP PLATE.
NAIL TO TOP PLATE WITH 3-10d NAILS. (PRE-DRILL BLOCK)
WHERE AN EXISTING RIM JOIST OR BLOCKING
STRUCTURAL PANEL BLOCKING INSTALLED TO
BRACED PANELS, ALTERNATE JOIST SPACES AT OTHER LOCATIONS
1-STORY: ALTERNATE JOIST SPACE
"
SEE FIGURE A304.4.1(2) FOR BRACING
EXISTING RIM JOIST WITH
EXISTING NAILING TO BE
VERIFIED PER A304.1.4
For SI: 1 inch = 25.4 mm, 1 pound = 4.4 N. NOTE: See Section A304.4 for cripple wall bracing.
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NEW 2x BLOCKING. SEE REQUIREMENTS
WHERE EXISTING NAILING FROM EXISTING RIM
JOIST TO TOP PLATE CANNOT BE VERIFIED
PROVIDE NEW ¾ WOOD STRUCTURAL PANEL" BLOCKING. SEE REQUIREMENTS ABOVE.
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[BS] A304.2 Foundations.
[BS] A304.2.1 New perimeter foundations. New perimeter foundations shall be provided for structures with the structural weaknesses noted in Items 1 and 2 of Section A303. Soil investigations or geotechnical studies are not required for this work unless the building is located in a special study zone as designated by the code official or other authority having jurisdiction.
[BS] A304.2.2 Evaluation of existing foundations. Partial perimeter foundations or unreinforced masonry foundations shall be evaluated by a registered design professional for the force levels specified in Section A301.3. Test reports or other substantiating data to determine existing foundation material strengths shall be submitted to the code official. Where approved by the code official, these existing foundation systems shall be strengthened in accordance with the recommendations included with the evaluation in lieu of being replaced.
Exception: In lieu of testing existing foundations to determine material strengths, and where approved by the code official, a new nonperimeter foundation system designed for the forces specified in Section A301.3 shall be used to resist lateral forces from perimeter walls. A registered design professional shall confirm the ability of the existing diaphragm to transfer seismic forces to the new nonperimeter foundations.
CEBC § 2.3.6 Medium relevance — show source text
- In the case of rotational restraint, the anchorage shall be designed to resist the axial and shear forces, and moments resulting from the seismic load effects including overstrength factor in accordance with Section 2.3.6 or 2.4.5 of ASCE 7 or the anchorage shall be capable of developing the full axial, bending and shear nominal strength of the element.
- The connection between the pile cap and the steel H-piles or unfilled steel pipe piles in structures assigned to Seismic Design Category D, E or F shall be designed for a tensile force of not less than 10 percent of the pile compression capacity.
2025 CALIFORNIA BUILDING CODE 18-29
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SOILS AND FOUNDATIONS
Exceptions:
- Connection tensile capacity need not exceed the strength required to resist seismic load effects including overstrength of ASCE 7 Section 12.4.3 or 12.14.3.2.
- Connections need not be provided where the foundation or supported structure does not rely on the tensile capacity of the piles for stability under the design seismic force. [OSHPD 1R, 2 & 5] Not permitted by OSHPD.
Where the vertical lateral-force-resisting elements are columns, the pile cap flexural strengths shall exceed the column flexural strength. The connection between batter piles and pile caps shall be designed to resist the nominal strength of the pile acting as a short column. Batter piles and their connection shall be designed to resist forces and moments that result from the application of seismic load effects including overstrength factor in accordance with Section 2.3.6 or 2.4.5 of ASCE 7.
1810.3.12 Grade beams. Grade beams shall comply with the provisions of ACI 318.
Exception: Grade beams not subject to differential settlement exceeding one-fourth of the thresholds specified in ASCE 7 Table 12.13-3 and designed to resist the seismic load effects including overstrength factor in accordance with Section 2.3.6 or 2.4.5 of ASCE 7 need not comply with ACI 318 Section 18.13.3.1.
1810.3.13 Seismic ties. Seismic ties shall comply with the provisions of ACI 318.
Exception: In Group R-3 and U occupancies of light-frame construction, deep foundation elements supporting foundation walls, isolated interior posts detailed so the element is not subject to lateral loads or exterior decks and patios are not subject to interconnection where the soils are of adequate stiffness, subject to the approval of the building official.
1810.4 Installation. Deep foundations shall be installed in accordance with Section 1810.4. Where a single deep foundation element comprises two or more sections of different materials or different types spliced together, each section shall satisfy the applicable conditions of installation.
1810.4.1 Structural integrity. Deep foundation elements shall be installed in such a manner and sequence as to prevent distortion or damage that would adversely affect the structural integrity of adjacent structures or of foundation elements being installed or already in place and as to avoid compacting the surrounding soil to the extent that other foundation elements cannot be installed properly.
CEBC § 1.3 Medium relevance — show source text
SECTION BO106—ADDITION
BO106.1 General. Where existing buildings with the addition are within the scope of this code, additions shall comply with this section and other applicable provisions of this code for new construction or as permitted by this appendix. Engineered design in accordance with Section R301.1.3 shall be permitted to meet the requirements of this section.
BO106.2 Structure for horizontal additions. Where an addition involves new construction attached to an existing building, the new construction shall meet all of the structural requirements of this code for new construction. Alterations to the existing building shall comply with the requirements governing alterations within this code. In wood light-frame additions, connection of the structural components shall be permitted to be provided using wall top plates and addition studs that abut the existing building. Wall top plates shall be lapped and spliced in accordance with Section R602.3.2. Abutting studs shall be fastened in accordance with Table R602.3(1).
Exception: The addition structure shall be permitted to be connected to the existing building in accordance with accepted engineering practice.
BO106.3 Structure for vertical additions. Where an addition involves new construction that adds a story to any part of the existing building or vertically increases the height of any part of the existing building, the new construction and the existing building together shall be shown to comply with, or altered to comply with, all of the structural requirements of this code for new construction.
Exception: Where the new structure and the existing structure together are evaluated in accordance with accepted engineering practice and are shown to be sufficient to support the combined loads from the new structure and existing structure, no structural alterations are required.
SECTION BO107—RELOCATED BUILDINGS
BO107.1 General. Residential buildings or structures moved into or within the jurisdiction are not required to comply with the requirements for new construction under this code, provided they comply with all of the following conditions:
The building shall be safe for human occupancy as determined by the California Fire Code and the International Property Maintenance Code .
Any repair, alteration or change of use undertaken within the relocated structure shall comply with the requirements of this code applicable to the work being performed.
Any field fabricated elements shall comply with the applicable requirements of this code.
SECTION BO108—REFERENCED STANDARDS
BO108.1 General. See Table BO108.1 for standards that are referenced in various sections of this appendix. Standards are listed by the standard identification with the effective date, the standard title and the section or sections of this appendix that reference the standard.
TABLE BO108.1—REFERENCED STANDARDS Col2 Col3 STANDARD ACRONYM STANDARD NAME SECTION HEREIN REFERENCED CEBC—25 California Existing Building Code BO102.8 CFC—25 California Fire Code BO107.1 IPMC—24 International Property Maintenance Code® BO107.1 APPENDIX BO-6 2025 CALIFORNIA RESIDENTIAL CODE
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CA RESERVED
2025 CALIFORNIA RESIDENTIAL CODE APPENDIX CA-1
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APPENDIX CA-2 2025 CALIFORNIA RESIDENTIAL CODE
CEBC § 3.1 Medium relevance — show source text
[BS] PERIMETER FOUNDATION. A foundation system that is located under the exterior walls of a building.
[BS] SNUGTIGHT. As tight as an individual can torque a nut on a bolt by hand, using a wrench with a 10-inch-long (254 mm) handle, and the point at which the full surface of the plate washer is contacting the wood member and slightly indenting the wood surface.
[BS] WOOD STRUCTURAL PANEL. A panel manufactured from veneers, wood strands or wafers or a combination of veneer and wood strands or wafers bonded together with waterproof synthetic resins or other suitable bonding systems. Examples of wood structural panels are:
Composite panels. A wood structural panel that is comprised of wood veneer and reconstituted wood-based material and bonded together with waterproof adhesive.
Oriented strand board (OSB). A mat-formed wood structural panel comprised of thin rectangular wood strands arranged in cross-aligned layers with surface layers normally arranged in the long panel direction and bonded with waterproof adhesive.
Plywood. A wood structural panel comprised of plies of wood veneer arranged in cross-aligned layers. The plies are bonded with waterproof adhesive that cures on application of heat and pressure.
2025 CALIFORNIA EXISTING BUILDING CODE APPENDIX A-27
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APPENDIX A—GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING BUILDINGS
SECTION A303—STRUCTURAL WEAKNESSES
[BS] A303.1 General. For the purposes of this chapter, any of the following conditions shall be deemed a structural weakness:
- Sill plates or floor framing that are supported directly on the ground without a foundation system that conforms to the building code.
- A perimeter foundation system that is constructed only of wood posts supported on isolated pad footings.
- Perimeter foundation systems that are not continuous.
Exceptions:
- Existing single-story exterior walls not exceeding 10 feet (3048 mm) in length, forming an extension of floor area beyond the line of an existing continuous perimeter foundation.
- Porches, storage rooms and similar spaces not containing fuel-burning appliances.
- A perimeter foundation system that is constructed of unreinforced masonry or stone.
- Sill plates that are not connected to the foundation or that are connected with less than what is required by the building code.
Exception: Where approved by the code official, connections of a sill plate to the foundation made with other than sill bolts shall be accepted if the capacity of the connection is equivalent to that required by the building code. 6. Cripple walls that are not braced in accordance with the requirements of Section A304.4 and Table A304.3.1, or cripple walls not braced with diagonal sheathing or wood structural panels in accordance with the building code.
SECTION A304—STRENGTHENING REQUIREMENTS
[BS] A304.1 General.
[BS] A304.1.1 Scope. The structural weaknesses noted in Section A303 shall be strengthened in accordance with the requirements of this section. Strengthening work may include both new construction and alteration of existing construction. Except as provided herein, all strengthening work and materials shall comply with the applicable provisions of the California Building Code .
CEBC § 1006.2.2.1 Medium relevance — show source text
Exits 1006.2.2.1
Bolts
Anchor rods 1901.3 Bonding, Masonry 1805.2.2, 2103.2.2, 2113.3.1, 2510.7 Bottle-Filling Stations 202 Braced Wall Line 202
Bracing 2308.10 Seismic requirements 2308.10.10.2, 2308.10.6.2, 2308.10.8 Sill anchorage 2308.10.7.3 Spacing 2308.10.1 Support 2308.10.8 Temporary 3103.5 Braced Wall Panel 202 Alternative bracing 2308.10.5.1, 2308.10.5.2
Connections 2308.10.7 Length 2308.10.4 Location 2308.10.2
Method 2308.10.3 Brick (see Masonry) Building Area (see Area, Building) 502.1, 503, 505, 506, 507, 508, 510 Demolition 3303
Existing 101.4.7 Fire walls 706.1 Height (see Height, Building) 502.1, 503, 504, 505, 508, 510 Occupancy classification Chapter 3 Party walls 706.1.1 Relocatable 3113
Replicable Appendix N Building, Existing 202 Building Department 103 Building Official Duties and powers 103, 104 Qualifications Appendix A Records 104.7
Termination A101.4 Building-Integrated Photovoltaic (BIPV) (see Photovoltaic) Built-Up Roof 1507.10 Business Occupancy (Group B) 303.1.1, 303.1.2, 304 Alarms and detection 907.2.2 Ambulatory care facilities 304, 422 Area 503, 505, 506, 507, 508 Height 503, 504, 505, 508, 510 Higher education laboratories 428, 2702.2
Incidental uses 509 Interior finishes Table 803.13, 804 Live load Table 1607.1 Means of egress Aisles 1018.3
Stairway, exit access 1019 Travel distance 1006.3, 1017.2,
1006.2.1
Mixed occupancies 508.2, 508.3, 508.4 Accessory 303.1.2, 508.2 Ambulatory care facilities 422 Assembly 303.1.2
Assembly spaces 1030 Exit signs 1013.1 Guards 1015.2, 1030.17 Main exit 1030.3
Frequently asked questions
Who decides whether CBC or CRC applies to the moved building?
The authority having jurisdiction determines which code applies based on the building type and occupancy; CEBC §1402.2.1 simply requires compliance with the applicable code (CBC or CRC).
What if I can’t put anchors through the sill plate top?
Appendix A permits alternative anchorage details (Figures A304.3.1(2)–(4)) provided each alternative connector meets the minimum shear capacity and spacing requirements in §A304.3.1.
Is it acceptable to reuse old sill bolts from the previous foundation?
Only if those anchors meet the applicable CBC/CRC performance and capacity requirements and the sill and fasteners are in sound condition; Appendix A requires verification of existing materials and replacement where damaged.
Are expansion anchors allowed?
Yes if they meet the installation and performance requirements, but not where their installation causes surface cracking of the foundation wall; follow §A304.3.1.
Do I always need a design professional for relocated-building anchorage?
If existing foundations are partial, unreinforced, or if the project involves structural weakness evaluations or new foundation design, Appendix A requires review/design by a registered design professional. See §A304.2.2 and related Appendix A sections.
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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