San Marino Municipal Code Art. 03 Residential Code

(Ord. 0-19-1357, 11-13-2019; Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, items 1, 3 and 5 of section R301.2.2.6 of the Residential Code are amended to read as follows:

1. When exterior shear wall lines or braced wall panels are not in one plane vertically from the foundation to the uppermost story in which they are required.

2. When the end of a braced wall panel occurs over an opening in the wall.

3. When portions of a floor level are vertically offset.

(Ord. 0-19-1357, 11-13-2019; Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R301.2.2.11 is added to the Residential Code to read as follows:

R301.2.2.11 Anchorage of Mechanical, Electrical, or Plumbing Components and Equipment. Mechanical, electrical, or plumbing components and equipment shall be anchored to the structure. Anchorage of the components and equipment shall be designed to resist loads in accordance with the International Building Code and ASCE 7, except where the component is positively attached to the structure and flexible connections are provided between the component and associated ductwork, piping, and conduit; and either

1. The component weighs 400 lb (1,780 N) or less and has a center of mass located 4 ft (1.22 m) or less above the supporting structure; or

2. The component weighs 20 lb (89N) or less or, in the case of a distributed system, 5 lb/ft (73 N/m) or less.

(Ord. 0-19-1357, 11-13-2019; Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R337 is added to the Residential Code to read as follows:

R337.1 Application-New Buildings. All new residential buildings of any occupancy that are located in the Very High Fire Hazard Severity Zone (VHFHSZ) as designated by the City of San Marino.

R337.2 Application-Additions & Remodels. The addition and remodeling areas of existing building of any occupancy that are located within the Very High Fire Hazard Severity Zone (VHFHSZ) as designated by the city of San Marino.

337.3 Protection of enclosed eaves. The exposed underside of enclosed roof eaves and soffits shall be protected on the exposed underside by one or more of the following:

1. Noncombustible materials.

2. Ignition-resistant building materials.

3. Materials approved for not less than 1-hour fire-resistance-rated construction on the exterior side, as tested in accordance with ASTM E119 or UL 263.

4. 2-inch (51 mm) nominal dimension lumber.

5. 1-inch (25 mm) nominal fire-retardant-treated lumber or 3/4-inch (19.1 mm) nominal fire-retardant-treated plywood, identified for exterior use and complying with Section 2303.2 of the California Building Code.

6. Boxed-in roof eave soffit assemblies with an underside that meets the performance criteria as determined by the Building Official when tested in accordance with the test procedures set forth in ASTM E2957.

7. Boxed-in roof eave soffit assemblies with an underside that meets the performance criteria in accordance with the test procedures set forth in SFM Standard 12-7A-3.

Facias are required and shall be ignition-resistant building materials, fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code, materials approved for not less than 1-hour fire-resistance rated construction or 2-inch (51 mm) nominal dimension lumber.

337.3.1 Protection of open eaves. The exposed roof deck on the underside of unenclosed roof eaves shall consist of one or more of the following:

1. Noncombustible material.

2. Ignition-resistant building material.

3. Fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code.

4. Materials approved for not less than 1-hour fire-resistance-rated construction on the exterior side, as tested in accordance with ASTM E119 or UL 263.

5. 2-inch (51 mm) nominal dimension lumber.

6. One layer of 5/8-inch (16 mm) Type X gypsum sheathing applied behind an exterior covering on the underside of the roof deck.

7. The exterior portion of a 1-hour fire-resistance-rated exterior assembly, as tested in accordance with ASTM E119 or UL 263, applied to the underside of the roof deck designed for exterior fire exposure, including assemblies using the gypsum panel and sheathing products listed in the Gypsum Association Fire Resistance Design Manual.

Facias, if provided, shall be of fire-retardant-treated wood labeled for exterior use and complying with Section 2303.2 of the California Building Code, ignition-resistant building materials, materials approved for not less than 1-hour fire-resistance-rated construction or 2-inch (51 mm) nominal dimension lumber.

337.10 Vents. Where provided, ventilation openings for enclosed attics, gable ends, ridge ends, under eaves and cornices, enclosed eave soffit spaces, enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters, underfloor ventilation, foundations and crawl spaces, or any other opening intended to permit ventilation, either in a horizontal or vertical surface, shall be in accordance with Section 337.10.1 or Section 337.10.2 to resist building ignition from the intrusion of burning embers and flame through the ventilation openings.

337.10.1 Performance requirements. Ventilation openings shall be fully covered with Wildfire Flame and Ember Resistant vents approved and listed by the California State Fire Marshal, or WUI vents, tested in accordance with ASTM E2886, to demonstrate compliance with all the following requirements:

1. There shall be no flaming ignition of the cotton material during the Ember Intrusion Test.

2. There shall be no flaming ignition during the Integrity Test portion of the Flame Intrusion Test.

3. The maximum temperature of the unexposed side of the vent shall not exceed 662°F (350°C).

337.10.2 Off ridge and ridge vents. Vents that are installed on a sloped roof, such as dormer vents, shall comply with all of the following:

1. Vents shall be covered with a mesh where the dimensions of the mesh therein shall be a minimum of 1/16 inch (1.6 mm) and shall not exceed 1/8 inch (3.2 mm) in diameter.

2. The vent and mesh material shall be noncombustible.

3. The vent and mesh material shall be corrosion resistant.

337.10.3 Vent locations. Gable-end and dormer vents shall be located not less than 10 feet (3048 mm) from lot lines. Underfloor ventilation openings shall be located as close to grade as practical.

(Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R401.1 of the Residential Code is amended to read as follows:

R401.1 Application. The provisions of this chapter shall control the design and construction of the foundation and foundation spaces for all buildings. In addition to the provisions of this chapter, the design and construction of foundations in areas prone to flooding as established by Table R301.2(1) shall meet the provisions of Section R322. Wood foundations shall be designed and installed in accordance with AF&PA PWF.

Exception: The provisions of this chapter shall be permitted to be used for wood foundations only in the following situations:

1. In buildings that have no more than two floors and a roof.

2. When interior basement and foundation walls are constructed at intervals not exceeding 50 feet (15 240 mm).

Wood foundations in Seismic Design Category D0, D1 or D2 shall not be permitted.

Exception: In non-occupied, single-story, detached storage sheds and similar uses other than carport or garage, provided the gross floor area does not exceed 200 square feet, the plate height does not exceed 12 feet in height above the grade plane at any point, and the maximum roof projection does not exceed 24 inches.

(Ord. 0-19-1357, 11-13-2019; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, sections R403.1.2, R403.1.3 and R403.1.5 of the Residential Code are amended to read as follows:

R403.1.2 Continuous footing in Seismic Design Categories Do, Di and D2. The braced wall panels at exterior walls of buildings located in Seismic Design Categories D0, D1 and D2 shall be supported by continuous footings. All required interior braced wall panels in buildings shall be supported by continuous footings.

R403.1.3 Seismic reinforcing. Concrete footings located in Seismic Design Categories D0, D1 and D2, as established in Table R301.2(1), shall have minimum reinforcement. Bottom reinforcement shall be located a minimum of 3 inches (76 mm) clear from the bottom of the footing.

In Seismic Design Categories D0, D1 and D2 where construction joint is created between a concrete footing and a stem wall, a minimum of one No. 4 bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall extend to 3 inches (76 mm) clear of the bottom of the footing, have a standard hook and extend a minimum of 14 inches (357 mm) into the stem wall.

In Seismic Design Categories D0, D1 and D2 where a grouted masonry stem wall is supported on a concrete footing and stem wall, a minimum of one No. 4 bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall extend to 3 inches (76 mm) clear of the bottom of the footing and have a standard hook.

In Seismic Design Categories D0, D1 and D2 masonry stem walls without solid grout and vertical reinforcing are not permitted.

Exception: In detached one- and two-family dwellings located in Seismic Design Category A, B or C which are three stories or less in height and constructed with stud bearing walls, isolated plain concrete footings, supporting columns or pedestals are permitted.

R403.1.5 Slope. The top surface of footings shall be level. The bottom surface of footings shall be permitted to have a slope not exceeding one unit vertical in 10 units horizontal (10-percent slope). Footings shall be stepped where it is necessary to change the elevation of the top surface of the footing or where the surface of the ground slopes more than one unit vertical in 10 units horizontal (10-percent slope).

For structures located in Seismic Design Categories D0, D1 or D2, stepped footings shall be reinforced with four No. 4 rebar. Two bars shall be place at the top and bottom of the footings as shown in Figure R403.1.5.

[Figure]

FIGURE R403.1.5

STEPPED FOOTING

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R404.2 of the Residential Code is amended to read as follows:

R404.2 Wood foundation walls. Wood foundation walls shall be constructed in accordance with the provisions of Sections R404.2.1 through R404.2.6 and with the details shown in Figures R403.1(2) and R403.1(3). Wood foundation walls shall not be used for structures located in Seismic Design Category D0, D1 or D2.

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R501.1 of the Residential Code is amended to read as follows:

R501.1 Application. The provisions of this chapter shall control the design and construction of the floors for all buildings including the floors of attic spaces used to house mechanical or plumbing fixtures and equipment. Mechanical or plumbing fixtures and equipment shall be attached (or anchored) to the structure in accordance with Section R301.2.2.11.

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R503.2.4 is added to the Residential Code to read as follows:

R503.2.4 Openings in horizontal diaphragms. Openings in horizontal diaphragms with a dimension perpendicular to the joist that is greater than 4 feet (1.2 m) shall be constructed in accordance with Figure R503.2.4.

[Figure]

a. Blockings shall be provided beyond headers.

b. Metal ties not less than 0.058 inch [1.47 mm (16 galvanized gage)] by 1.5 inches (38 mm) wide with eight 16d common nails on each side of the header-joist intersection. The metal ties shall have a minimum yield of 33,000 psi (227 MPa).

c. Openings in diaphragms shall be further limited in accordance with Section R301.2.2.2.5.

FIGURE R503.2.4

OPENINGS IN HORIZONTAL DIAPHRAGMS

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, lines 37 and 38 of table R602.3(1) of the Residential Code are amended to read as follows:

TABLE R602.3(1) - continued

FASTENER SCHEDULE FOR STRUCTURAL MEMBERS

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s; 1 Ksi = 6.895 MPa.

a. All nails are smooth-common, box or deformed shanks except where otherwise stated. Nails used for framing and sheathing connections shall have minimum average bending yield strengths as shown: 80 ksi for shank diameter of 0.192 inch (20d common nail), 90 ksi for shank diameters larger than 0.142 inch but not larger than 0.177 inch, and 100 ksi for shank diameters of 0.142 inch or less.

b. Nails shall be spaced at not more than 6 inches on center at all supports where spans are 48 inches or greater.

c. Four-foot by 8-fool or 4-foot by 9-foot panels shall be applied vertically.

d. Spacing of fasteners not included in this table shall be based on Table R602.3(2).

e. For regions having basic wind speed of 110 mph or greater, 8d deformed (2'/2"x 0.120) nails shall be used for attaching plywood and wood structural panel roof sheathing to framing within minimum 4S-inch distance from gable end walls, if mean roof height is more than 25 feet, up to 35 feet maximum.

f. For regions having bask wind speed of 100 mph or less, nails for attaching wood structural panel roof sheathing to gable end wall framing shall be spaced 6 inches on center. When basic wind speed is greater than 100 mph, nails for attaching panel roof sheathing to intermediate supports shall be spaced 6 inches on center for minimum 48-inch distance from ridges, eaves and gable end walls; and 4 inches on center to gable end wall framing.

g. Gypsum sheathing shall conform to ASTM C 1396 and shall be installed in accordance with GA 253. Fiberboard sheathing shall conform to ASTM C 208.

h. Spacing of fasteners on floor sheathing panel edges applies to panel edges supported by framing members and required blocking and at all floor perimeters only. Spacing of fasteners on roof sheathing panel edges applies to panel edges supported by framing members and required blocking. Blocking of roof or floor sheathing panel edges perpendicular to the framing members need not be provided except as required by other provisions of this code. Floor perimeter shall be supported by framing members or solid blocking.

i. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule, provide two toe nails on one side of the rafter and toe nails from the ceiling joist to top plate in accordance with this schedule. The toe nail on the opposite side of the rafter shall not be required.

j. Use of staples in braced wa9 panels snail be prohibited in Seismic Design Category D0, D1, or D2.

(Ord. 0-19-1357, 11-13-2019; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, footnote "b" of table R602.3(2) of the Residential Code is amended to read as follows:

b. Staples shall have a minimum crown width of 7/16-inch on diameter except as noted. Use of staples in roof, floor, subfloor, and braced wall panels shall be prohibited in Seismic Design Category D0, D1, or D2.

(Ord. 0-19-1357, 11-13-2019; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, table R602.10.3(3) of the Residential Code is amended to read as follows:

[Figure]

[Figure]

[Figure]

(Ord. 0-19-1357, 11-13-2019)

Notwithstanding the provisions of section 25.03.01 of this article, table R602.10.4 of the Residential Code is amended to read as follows:

[Figure]

[Figure]

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, figure R602.10.6.1 of the Residential Code is amended to read as follows:

[Figure]

(Ord. 0-19-1357, 11-13-2019; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, figure R602.10.6.2 of the Residential Code is amended to read as follows:

[Figure]

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, table R602.10.5 of the Residential Code is amended to read as follows:

TABLE 602.10.6.5.4

MINIMUM LENGTH OF BRACED WALL PANELS

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.

NP = Not Permitted.

a. Linear interpolation shall be permitted.

b. Use the actual length when it is greater than or equal to the minimum length.

c. Maximum header height for PFH is 10 feet in accordance with Figure R602.10.6.2, but wall height may be increased to 12 feet with pony wall.

d. Maximum opening height for PFG is 10 feet in accordance with Figure R602.10.6.3. but wall height maybe increased to 12 feet with pony wall.

e. Maximum opening height for CS-PF is 10 feet in accordance with Figure R602.10.6.4. but wall height may be increased to 12 feet with pony wall.

(Ord. 0-19-1357, 11-13-2019; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R602.10.2.3 of the Residential Code is amended to read as follows:

R602.10.2.3 Minimum number of braced wall panels. Braced wall lines with a length of 16 feet (4877 mm) or less shall have a minimum of two braced wall panels of any length or one braced wall panel equal to 48 inches (1219 mm) or more. Braced wall lines greater than 16 feet (4877 mm) shall have a minimum of two braced wall panels. No braced wall panel shall be less than 48 inches in length in Seismic Design Category D0, D1, or D2.

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R606.4.4 of the Residential Code is amended to read as follows:

R606.4.4 Parapet walls. Unreinforced solid masonry parapet walls shall not be less than 8 inches (203 mm) thick and their height shall not exceed four times their thickness. Unreinforced hollow unit masonry parapet walls shall be not less than 8 inches (203 mm) thick, and their height shall not exceed three times their thickness. Masonry parapet walls in areas subject to wind loads of 30 pounds per square foot (1.44 kPa) or located in Seismic Design Category

D0, DI or D2, or on townhouses in Seismic Design Category C shall be reinforced in accordance with Section R606.12.

(Ord. 0-19-1357, 11-13-2019; amd. Ord. O-22-1400, 1-11-2023 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of Section 25.03.01 of this article, section R606.12.2.2.3 of the Residential Code is amended to read as follows:

R606.12.2.2.3 Reinforcement requirements for masonry elements. Masonry elements listed in Section R606.12.2.2.2 shall be reinforced in either the horizontal or vertical direction as shown in Figure R606.11(3) and in accordance with the following:

1. Horizontal reinforcement. Horizontal joint reinforcement shall consist of at least one No. 4 bar spaced not more than 48 inches (1219 mm).Horizontal reinforcement shall be provided within 16 inches (406 mm) of the top and bottom of these masonry elements.

2. Vertical reinforcement. Vertical reinforcement shall consist of at least one No. 4 bar spaced not more than 48 inches (1219 mm). Vertical reinforcement shall be within 8 inches (406mm) of the ends of masonry walls.

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R602.3.2, Exception, of the Residential Code is amended to read as follows:

Exception: In other than Seismic Design Category D0, D1 or D2, a single top plate may be installed in stud walls, provided the plate is adequately tied at joints, corners and interesting walls by a minimum 3-inch-by-6-inch by a 0.036-inch-thick (76 mm by 152 mm by 0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by six 8d nails on each side, provided the rafters or joists are centered over the studs with a tolerance of no more than 1 inch (25 mm). The top plate may be omitted over lintels that are adequately tied to adjacent wall sections with steel plates or equivalent as previously described.

(Ord. 0-19-1357, 11-13-2019 ; amd. Ord. O-25-1423-U, 9-26-2025)

Notwithstanding the provisions of section 25.03.01 of this article, section R803.2.4 is added to the Residential Code to read as follows:

R803.2.4 Openings in horizontal diaphragms. Openings in horizontal diaphragms shall conform with Section R503.2.4.

(Ord. 0-19-1357, 11-13-2019)

Notwithstanding the provisions of section 25.03.01 of this article, section R1001.3.1 of the Residential Code is amended to read as follows:

R1001.3.1Vertical reinforcing. For chimneys up to 40 inches (1016 mm) wide, four No. 4 continuous vertical bars adequately anchored into the concrete foundation shall be placed between wythes of solid masonry or within the cells of hollow unit masonry and grouted in accordance with Section R609. Grout shall be prevented from bonding with the flue liner so that the flue liner is free to move with thermal expansion. For chimneys more than 40 inches (1016 mm) wide, two additional No. 4 vertical bars adequately anchored into the concrete foundation shall be provided for each additional flue incorporated into the chimney or for each additional 40 inches (1016 mm) in width or fraction thereof.

(Ord. 0-19-1357,