CODES

ADOPTS WITH AMENDMENTS:

International Residential Code 2015 (IRC 2015)

Part I ‒ Administrative

Chapter 1 Scope and Administration

Part II ‒ Definitions

Chapter 2 Definitions

Part III ‒ Building Planning and Construction

Chapter 3 Building Planning

Chapter 4 Foundations

Chapter 5 Floors

Chapter 6 Wall Construction

Chapter 7 Wall Covering

Chapter 8 Roof-Ceiling Construction

Chapter 9 Roof Assemblies

Chapter 10 Chimneys and Fireplaces

Part IV ‒ Energy Conservation

Chapter 11 [RE] Energy Efficiency

Part V ‒ Mechanical

Chapter 12 Mechanical Administration

Chapter 13 General Mechanical System Requirements

Chapter 14 Heating and Cooling Equipment and Appliances

Chapter 15 Exhaust Systems

Chapter 16 Duct Systems

Chapter 17 Combustion Air

Chapter 18 Chimneys and Vents

Chapter 19 Special Appliances, Equipment and Systems

Chapter 20 Boilers and Water Heaters

Chapter 21 Hydronic Piping

Chapter 22 Special Fuel oil Piping and Storage Systems

Chapter 23 Solar Thermal Energy Systems

Part VI ‒ Fuel Gas

Chapter 24 Fuel Gas

Part VII ‒ Plumbing

Chapter 25 Plumbing Administration

Chapter 26 General Plumbing Requirements

Chapter 27 Plumbing Fixtures

Chapter 28 Water Heaters

Chapter 29 Water Supply and Distribution

Chapter 30 Sanitary Drainage

Chapter 31 Vents

Chapter 32 Traps

Chapter 33 Storm Drainage

Part VIII ‒ Electrical

Chapter 34 General Requirements

Chapter 34 GENERAL REQUIREMENTS

Chapter 35 Electrical Definitions

Chapter 35 ELECTRICAL DEFINITIONS

Chapter 36 Services

Chapter 36 SERVICES

Chapter 37 Branch Circuit and Feeder Requirements

Chapter 37 BRANCH CIRCUIT AND FEEDER REQUIREMENTS

Chapter 38 Wiring Methods

Chapter 38 WIRING METHODS

Chapter 39 Power and Lighting Distribution

Chapter 39 POWER AND LIGHTING DISTRIBUTION

Chapter 40 Devices and Luminaires

Chapter 40 DEVICES AND LUMINAIRES

Chapter 41 Appliance Installation

Chapter 41 APPLIANCE INSTALLATION

Chapter 42 Swimming Pools

Chapter 42 SWIMMING POOLS

Chapter 43 Class 2 Remote-Control, Signaling and Power-Limited Circuits

Chapter 43 CLASS 2 REMOTE-CONTROL, SIGNALING AND POWER-LIMITED CIRCUITS

Part IX ‒ Referenced Standards

Chapter 44 Referenced Standards

Chapter 45 HIGH WIND ZONES

Chapter 46 COASTAL AND FLOOD PLAIN CONSTRUCTION STANDARDS

Appendix A Sizing and Capacities of Gas Piping

Appendix B Sizing of Venting Systems Serving Appliances Equipped With Draft Hoods, Category I Appliances, and Appliances Listed for Use With Type B Vents

Appendix C Exit Terminals of Mechanical Draft and Direct-Vent Venting Systems

Appendix D Recommended Procedure for Safety Inspection of an Existing Appliance Installation

Appendix E Manufactured Housing Used as Dwellings

Appendix E (E-1 THROUGH E-4)
RESIDENTIAL REQUIREMENTS FOR ENERGY CONSERVATION

Appendix F Radon Control Methods

Appendix G Piping Standards for Various Applications

Appendix H Patio Covers

Appendix I Private Sewage Disposal

Appendix J Existing Buildings and Structures

Appendix J EXISTING BUILDINGS AND STRUCTURES

Appendix K Sound Transmission

Appendix L Permit Fees

Appendix M HOME DAY CARE—R-3 OCCUPANCY

Appendix M WOOD DECKS

Appendix N Venting Methods

Appendix O Automatic Vehicular Gates

Appendix O FOAM PLASTIC DIAGRAMS

Appendix P Sizing of Water Piping System

Appendix Q Reserved

Appendix Q DISCONTINUOUS FOOTINGS

Appendix R Light Straw-Clay Construction

Appendix S Strawbale Construction

Appendix T Recommended Procedure for Worst-Case Testing of Atmospheric Venting Systems Under N1102.4 or N1105 Conditions ≤ 5ACH50

Appendix U SOLAR-READY PROVISIONS—DETACHED ONE- AND TWO-FAMILY DWELLINGS, MULTIPLE SINGLE- FAMILY DWELLINGS (TOWNHOUSES)

Appendix V SWIMMING POOLS, SPAS AND HOT TUBS

Appendix W BASIC LOAD ESTIMATING

Chapter 45 HIGH WIND ZONES

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

Section R4501 GENERAL

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

R4501.1 General

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The provisions of this chapter shall be applicable to buildings constructed in high wind zones as noted by the text. These provisions shall be in addition to or in lieu of previous chapters.

R4501.2 Alternate construction

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
In lieu of specific code requirements for structures in the 130, 140, and 150 miles per hour (58 m/s, 63 m/s and 67 m/s) wind zones, compliance with International Code Council ICC 600 Standard for Residential Construction in High-Wind Regions or AF&PA Wood Frame Construction Manual for One- and Two-Family Dwellings is acceptable.

Section R4502 DESIGN PRESSURE FOR DOORS AND WINDOWS

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
TABLE R4502(a)
DESIGN PRESSURES FOR DOORS AND WINDOWSa, b, c, d POSITIVE AND NEGATIVE IN PSF
VELOCITY (mph) MEAN ROOF HEIGHT (feet)
15 25 35e
130 25 29 32
140 31 35 39
150 37 43 47
For SI: 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 degree = 0.01745 rad.
  1. Alternative pressures may be determined by using the North Carolina Building Code, ASCE-7, or the International Building Code.
  2. If window or door is more than 4 feet from a corner, the pressure from this table shall be permitted to be multiplied by 0.87. This adjustment does not apply to garage doors.
  3. For windows or doors in structures with a roof slope of 10 degrees (2:12) or less from the horizontal, the pressure from this table may be multiplied by 0.90.
  4. Design pressure ratings based on the standards listed in Section R609 are adequate documentation of capacity to resist pressures from the table.
  5. Where the mean roof height exceeds this table, values shall be determined by a design professional.
TABLE R4502(b)
DESIGN PRESSURES (IN PSF) GARAGE DOORSa, b, c, d, e
VELOCITY (mph) MEAN ROOF HEIGHT (feet)
15 25 35f
130 20 23 26
140 25 29 32
150 30 35 39
For SI: 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 degree = 0.01745 rad.
  1. The pressures in this table are for garage doors at least 9 feet by 7 feet and at least 2 feet from the corner.
  2. Alternative design pressures may be determined by using the North Carolina Building Code, ASCE-7, or the International Building Code.
  3. For doors in a structure with a roof slope of 10 degrees (2:12) or less from the horizontal the pressures from this table may be multiplied by 0.90.
  4. Design pressure ratings based on tests done according to ASTM E330 are adequate documentation.
  5. Garage doors on the ground level of a structure in a flood zone do not have to meet the above design pressures provided all of the following conditions are met:
    1. Structure is anchored to the girders and top of the piling to resist the forces given in Chapter 45.
    2. The garage door occurs below the top of the piling.
    3. Provide openings at the garage level that comply with either of the following options:
      1. Design all exterior walls at the garage level to break away at 20 psf or less; or
      2. Provide openings (in walls at the garage level without the garage level without the garage door) equal to at least 20 percent of the total wall area from the ground to the roof.
  6. Where the mean roof height exceeds this table, values shall be determined by a design professional.

Section R4503 FOOTINGS

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

R4503.1 General

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
All exterior walls shall be supported on continuous concrete footings in the 140 and 150 mph (63 m/s and 67 m/s) wind zones. Exterior wall footings in the 130 mph (58 m/s) wind zone shall be constructed in accordance with Section R403.1.

Exception: Pile foundations shall be constructed in accordance with Chapter 46.

R4503.1.1 Footing size

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Footings shall be a minimum of 8 inches by 24 inches (203 mm by 610 mm) for houses two and one-half stories and less. The footings for a three-story building shall be 10 inches by 24 inches (254 mm by 610 mm).

Exception: Alternative footing sizes are permitted when a footing mass equivalent is provided to resist uplift forces. See Figure R4503.1.1.

FIGURE R4503.1.1
ALTERNATIVE FOOTING SIZE

R4503.1.2 Footing reinforcement

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Footings shall be reinforced with three #4 bars or two #5 bars at 3 inches (76 mm) above the bottom of the footing. The bars shall be equally spaced with 3 inches (76 mm) clear minimum from the side of the footing. The bars shall be continuous or lapped 25 inches at all splices.

R4503.1.3 Interior piers and pier footings

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The dimensions for the interior piers and pier footings shall comply with Table R403.1(2).

R4503.1.4 Interior thickened slabs

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Monolithic slabs with integral footings resisting uplift shall be reinforced in accordance with Section R4503.1.2.

R4503.1.5 Interior foundation walls

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Interior foundation walls resisting uplift shall be reinforced in accordance with Section R4503.1.2.

R4503.2 Pier and curtain wall footings

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Pier and curtain walls in the 140 and 150 mph (63 m/s and 67 m/s) wind zones shall be constructed in accordance with Sections R4503.2.1 and R4503.2.2 and Figures R4503.2(a) through R4503.2(d).

FIGURE R4503.2(a)
CONTINUOUS VENEER PIER/CURTAIN WALL


FIGURE R4503.2(b)
CONTINUOUS VENEER PIER/CURTAIN WALL


FIGURE R4503.2(c)
VENEER SHIRT WALL PIER/CURTAIN WALL


FIGURE R4503.2(d)
VENEER SHIRT WALL PIER/CURTAIN WALL

R4503.2.1 Enlarged footings at piers

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The curtain wall footing must meet the minimum projection requirements in Figure R403.1(1) and footing dimensions for the pier footings shall comply with Table R4503.2.1.

TABLE R4503.2.1
FOOTINGS TO RESIST UPLIFT FROM PIERS IN 140 AND 150 MPH WIND ZONES SUPPORTING GIRDERS IN EXTERIOR WALLS
FOOTING SIZE GIRDER SPAN
VELOCITY (mph) 4'-0″ 6'-0″ 8'-0″
140 2'-0″ × 2'-0″ × 10″ 2'-4″ × 2'-4″ × 10″ 2'-8″ × 2'-8″ × 10″
150 3'-0″ × 3'-0″ × 10″ 3'-4″ × 3'-4″ × 12″ 3'-8″ × 3'-8″ × 12″
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s.
Note: See Table R403.1(2) for 130 mph wind zone.

R4503.2.2 Continuous width footings

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Uniform continuous width footings for pier and curtain wall foundations shall be a minimum of 8 inches (203 mm) thick and 24 inches (60 mm) wide. Footings shall be reinforced with three #4 bars (or two #5 bars) at 3 inches (76 mm) above the bottom of the footing. The bars shall be continuous or lapped 25 inches (635 mm) at all splices.

R4503.3 Footing dowels

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
All footings shall have reinforcing dowel bars to match the vertical reinforcing bars in the foundation wall above. Dowels or threaded rods shall have a standard hook length of 12 times the bar diameter embedded in the footing and shall lap the wall or pier reinforcing at least 25 inches (635 mm).

R4503.4 Footing anchor bolts

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
All anchor bolts shall have a standard hook length of 12 times the bolt diameter embedded in the footing or foundation wall. They shall not be permitted to be lapped.

Exceptions:
  1. Anchor bolts in bond beams as permitted by Section R4504.2.1.1
  2. Anchor bolts in slabs on grade as permitted by Section R4504.2.2

Section R4504 WALL AND FOUNDATION ANCHORAGE

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

R4504.1 Anchorage in the 130 mph wind zone

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Exterior walls of structures in the 130 mph (58 m/s) wind zone shall be anchored to the foundation wall or slab on grade with ½-inch (13 mm) anchor bolts, 4 feet (1219 mm) on center extended 15 inches (381 mm) into masonry and 7 inches (178 mm) into concrete and are exempt from the other requirements of this section.

R4504.2 Anchorage in the 140 and 150 mph wind zones

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Exterior walls of structures in the 140 and 150 mph (63 m/s and 67 m/s) wind zones shall be anchored to the footing to resist the forces specified in Section R4508.2, by the prescriptive requirements of this section and Figures R4504.2(a) through R4504.2(f), or as allowed by Section R4508.4.

FIGURE R4504.2(a)
FOUNDATION WALL WITH BOND BEAM


FIGURE R4504.2(b)
FOUNDATION WALL WITH UPLIFT ANCHOR BOLTS FROM FOOTING TO SILL PLATE


FIGURE R4504.2(c)
FOUNDATION WALL WITH UPLIFT ANCHOR BOLTS CONTINUOUS FROM FOOTING TO EXTERIOR WALL FRAMING


FIGURE R4504.2(d)
EXTERIOR CONCRETE SLAB ON GRADE FOOTING— DOUBLE SOLE PLATE


FIGURE R4504.2(e)
EXTERIOR CONCRETE SLAB ON GRADE FOOTING— SINGLE SOLE PLATE


FIGURE R4504.2(f)
GROUND SUPPORTED SLAB WITH MASONRY STEM WALL

R4504.2.1 Exterior foundation walls

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Vertical reinforcement bars shall be installed not more than 2 feet (51 mm) from each corner and at intervals not to exceed Table R4504.2.1 with all reinforced cells grouted solid. The reinforcement bars shall terminate in a bond beam in accordance with Section R4504.2.1.1 or continuous anchorage bolts shall terminate at the sill plate or exterior wall framing in accordance with Section R4504.2.1.2.

TABLE R4504.2.1
WALL REINFORCEMENT BARS OR CONTINUOUS ANCHORAGE BOLTSa, b, c, d
BAR/BOLT SIZE (inches) ½
MAXIMUM SPACING (inches) 96 72 42
For SI: 1 inch = 25.4 mm.
  1. Applies to 140 and 150 mph wind zones.
  2. Continuous anchorage from footing to girder or wall framing.
  3. Applies to footing dowel bars, vertical reinforcement and anchor bolts.
  4. Spacing may exceed the tabulated values by up to 8 inches provided the total number of required bars is installed.

R4504.2.1.1 Bond beams

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The top of a concrete or masonry foundation wall shall have a bond beam in accordance with Figure R4504.2(a). The bond beam shall be reinforced with one #5 bar. The bar shall be continuous or lapped 25 inches (635 mm) at all splices.

TABLE R4504.2.1.1
ANCHOR BOLT SPACINGa
WIND SPEED (mph) 140 150
MAXIMUM SPACING (inches) 21 18
For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s.
  1. Required spacing of ½-inch anchor bolts where a bond beam is required and for slab on grade with a single sole plate. See Figure R403.1(1) for 130 mph or less.

R4504.2.1.1.1 Bond beam plate anchorage

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
A minimum of two 2 × 6 sill plates shall be anchored with ½-inch (13 mm) anchor bolts with 2 × 2 × ⅛ inch (51 × 51 × 3 mm) washers at intervals not to exceed Table R4504.2.1.1. An approved anchor from the sill plate to the wall framing shall be installed to resist the forces specified in Table R4508.2 or sheathing shall be fastened in accordance with Figure R4508.4(b). See Figure R4504.2(a).

R4504.2.1.2 Continuous anchorage bolts

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
A minimum of two 2 × 6 sill plates shall be anchored with continuous anchor bolts in accordance with Table R4504.2.1 with 2 × 2 × ⅛ inch (51 × 51 × 3 mm) washers. Where the vertical anchorage bolts terminate at the sill plate, an approved anchor from the sill plate to the wall framing shall be installed to resist the forces specified in Table R4508.2 or sheathing shall be fastened in accordance with Figure R4508.4(b). See Figure R4504.2(b).

Exception: Where the uplift anchorage bolts from Table R4504.2.1 are continuous from the footing to the exterior wall framing, a single 2 × 6 sill plate is permitted. See Figure R4504.2(c).

R4504.2.2 Exterior concrete slab-on-grade footings

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Anchorage shall be installed at intervals not to exceed Table R4504.2.1 and shall terminate in a minimum 2 × 4 double sole plate. See Figure 4504.2(d).

Exceptions:
  1. Where the bolts terminate in a single sole plate, anchorage shall be installed at intervals not to exceed Table R4504.2.1.1. See Figure R4504.2(e).
  2. Foundation anchorage spaced and installed in accordance with the manufacturer’s installation instructions that provides equivalent anchorage to resist the forces in Table R4508.2 shall be installed to provide continuous load path from the single sole plate to the wall.

R4504.2.3 Ground supported slab with masonry stem wall

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
A minimum of two 2× sill plates shall be anchored with ½-inch (13 mm) continuous anchor bolts with 2 × 2 × ⅛ inch (51 × 51 × 3 mm) washers at intervals not to exceed Table R4504.2.1.1. An approved anchor from the sill plate to the wall framing shall be installed to resist the forces specified in Table R4508.2 or sheathing shall be fastened in accordance with Figure R4508.4(b). See Figure R4504.2(f).

Section R4505 WALL CONSTRUCTION

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
TABLE R4505(a)
STUDS IN 130, 140, AND 150 MPH ZONES Requirements for Wood Stud In: Exterior Walls Supporting One Floor, Roof and Ceiling or Less/Exterior Nonloadbearing Walls in Two Story Structure or Less/Interior Walls Supporting One Floor, Roof and Ceiling or Less
STUD LENGTH STUD SPACING 130 MPH 130 MPH 140 MPH 150 MPH
2 x 4 2 x 6 2 x 4 2 x 6 2 x 4 2 x 6 2 x 4 2 x 6
Species: Spruce Pine Fir (South) without Structural Sheathing Species: Spruce Pine Fir (South) with ⅜″ Wood Structural Sheathing
8 16 #2 Stud Stud Stud Stud Stud #2 Stud
8 24 #2 Stud #2 Stud #2 Stud #2 Stud
10 16 #2 Stud #2 Stud #2 Stud #2 Stud
10 24 Design #2 Design #2 Design #2 Design #2
Species: Spruce Pine Fir without Structural Sheathing Species: Spruce Pine Fir with ⅜″ Wood Structural Sheathing
8 16 Stud Stud Stud Stud Stud Stud #3 Stud
8 24 #2 Stud #3 Stud #2 Stud #2 Stud
10 16 #2 Stud #2 Stud #2 Stud #2 Stud
10 24 Design Stud #2 Stud Design Stud Design Stud
For SI: 1 inch = 25.4 mm, 1 mile per hour = 0.447 m/s.
Explanation of Table Entries:
Design – Studs with this entry shall be in accordance with accepted engineering practice.
#2 – #2 Grade construction
#3 – #3 Grade
Stud – Stud grade
Standard – Standard grade
Utility – Utility grade
⅜″ wood structural sheathing shall be attached with 8d nails at 6″ at perimeter and 12″ at intermediate supports. When a grade is specified in the table any grade above it in this list may be used.


TABLE R4505(b)
EXTERIOR WALLS FOR FIRST FLOOR OF THREE STORY
EXTERIOR BEARING WALLSa, b, c, d, e FIRST FLOOR OF THREE STORY
Spruce Pine Fir
WIND ZONE (mph) 2 × 4 @ 12″ o.c.
Structural Sheathing
3 × 4 or 2 × 6 @ 16″o.c.
Structural Sheathing
130 #2 Any grade
140 #2 Any grade
150 #2 Any grade
Exterior Nonbearing Wallsa, b, c, d, e, f First Floor of Three Story
Spruce Pine Fir
WIND ZONE (mph) 2 × 4 @ 12″ o.c.
Blocking
2 × 4 @ 16″ o.c.
Blocking
3 × 4 or 2 × 6 @ 16″ o.c.
Structural Sheathing
130 #2, Stud #2 Any grade
140 #2, Stud NP Any grade
150 #2 NP Any grade
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
  1. Any grade = any grade except standard, utility and economy.
  2. Corner bracing is required where blocking is specified.
  3. 2 – 2 × 4s at 16 inches or 1 – 2 × 4 at 8 inches may be used where 3 × 4 at 16 inches is specified.
  4. Refer to Sections R4506 and R4508.4 for sheathing requirements.
  5. Bearing stud height is limited to 10 feet.
  6. 2× full depth blocking at mid-height.

R4505.1 Construction

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Exterior walls of wood frame construction shall be in accordance with Figures R602.3(1) and R602.3(2). Components of exterior walls shall be fastened in accordance with Table R602.3(1). Walls of wood frame construction shall be designed and constructed in accordance with ANSI AWC National Design Specification for Wood Construction, listed in Chapter 44.

     Exterior walls subject to wind speeds of 130 mph (58 m/s) or greater as established in Table R301.2(1) shall be designed in accordance with accepted engineering practice. See Tables R4505(a) and R4505(b).

     In bearing walls, studs which are not more than 10 feet (3048 mm) in length shall be spaced not more than is specified in Tables R4505(a) and R4505(b) for the corresponding stud size.

Section R4506 STRUCTURAL BRACING

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

R4506.1 Structural bracing in 130 mph wind zone

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Structural bracing in the 130 mph (58 m/s) wind zone shall comply with Section R602.10.3.

R4506.2 Structural bracing in 140 and 150 mph wind zones

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
All stories shall be continuously sheathed with wood structural panels. All panels shall be fastened in accordance with Table R4506.2. Where sheathing is used to resist uplift, see Section R4508.4 for blocking requirements. Otherwise, blocking shall be installed if less than 50 percent of the wall length is sheathed. If a wall is sheathed less than 25 percent of its length, then that wall shall be designed in accordance with approved engineering practice.

TABLE R4506.2
PANEL FASTENER SPACINGa
BLOCKING
REQUIRED
NO BLOCKING
REQUIRED
Center of Panel 6″ 12″
Vertical Edge of Panel 6″ 6″
Horizontal Edge of Panel 3″ 3″
For SI: 1 inch = 25.4 mm.
  1. Table based on 8d nails.

R4506.3 Gable endwalls

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Gable endwalls in the 130, 140 and 150 mph (58 m/s, 63 m/s and 67 m/s) wind zones shall either be supported by lateral bracing at the ceiling or have continuous studs from the floor to the roof. 2 × 4 studs at 16 inches (406 mm) on center are limited to 10 feet (3048 mm) in length between supports. Nonbearing 2 × 6 SPF #2 studs at 16 inches (406 mm) on center with ⅜-inch (9 mm) wood structural panel sheathing are limited to unsupported lengths of 18 feet (5486 mm) in 130 mph (58 m/s), 16 feet (4877 mm) in 140 mph (53 m/s) and 14 feet (4267 mm) in 150 mph (67 m/s) wind zones. Where open web trusses are installed, wood structural panel sheathing shall extend 12 inches (305 mm) beyond horizontal construction joints. Where the horizontal joint occurs over minimum 1 inch (25 mm) thick OSB or plywood or 2× rimboard, a minimum 1½ inch (38 mm) overlap is required.

R4506.4 Lateral support at ceiling

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Where studs are not continuous, the ceiling must be used to support the endwall. 2 × 4 lateral bracing shall be installed on the top of ceiling joists or truss bottom chords at 8 feet (2438 mm) on center and extend 8 feet (2438 mm) inward from the gable endwall. See Figure R4506.7(a).

R4506.5 Full height studs

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Full height studs may be sized using the bracing at the ceiling to limit the stud length. See Figure R4506.5.

FIGURE R4506.5
GABLE ENDWALL BALLOON FRAMING PREFERRED METHOD

R4506.6 Cathedral endwalls

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Studs shall be continuous from the uppermost floor to either the ceiling or the roof.

R4506.7 Overhang at endwalls

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The overhang is limited to 12 inches (305 mm) where a laddered soffit is installed. The overhang may be increased to 24 inches (610 mm) where outlookers are framed over a dropped endwall into the first rafter or truss. See Figures R4506.7(a) and R4506.7(b). If the overhang exceeds 24 inches (610 mm), then the overhang shall be designed in accordance with approved engineering practice.

FIGURE R4506.7(a)
OVERHANG AT ENDWALLS


FIGURE R4506.7(b)
GABLE END OVERHANG


FIGURE R4506.7(c)
GABLE END OVERHANG

R4506.8 Roof sheathing attachment

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
The roof sheathing panel edges shall be blocked and nailed at the end two rafter or truss spaces. See Figure R4506.8.

Exception: The panel edges need not be blocked where 2 × 4 diagonal braces are framed from the top of the endwall to the lateral bracing at the ceiling.

FIGURE R4506.8
ROOF SHEATHING ATTACHMENT PLAN

Section R4507 MASONRY WALL CONSTRUCTION

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

R4507.1 Reinforcement

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Masonry walls subject to wind speeds of 140 mph (63 m/s) or greater, as established in Table R301.2(1), shall be constructed in accordance with Table R4507.1 or the requirements of Figures R4507.1(a) and R4507.1(b) and this section. Additionally, the minimum area of reinforcement shall not be less than 0.002 times the gross cross-sectional area wall, not more than two-thirds of which may be used in either direction. No required vertical reinforcement shall be less than ⅜ inch (9.5 mm) in diameter. Principal wall reinforcement shall have a maximum spacing of 4 feet (1219 mm) on center.

     For 130 mph (58 m/s) wind zones, see Figure R606.11(1) and Table R606.6.4.

TABLE R4507.1
H/T LATERAL SUPPORT RATIOS FOR UNREINFORCED EXTERIOR MASONRY WALLSa, b, d, e
ULTIMATE WIND SPEED, MPHc
Wall Construction 140 150
Solid masonry units 13 11
Hollow concrete masonry units or masonry bonded hollow walls 9 8
Cavity walls identical wythes The H/t ratio shall be 0.70 of the H/t ratio for single wythe walls. The t-value shall be the sum of the nominal thickness of the individual wythes.
Cavity walls with wythes of different types or size masonry The wall shall be designed based on ACI-530 or the H/t ratio may be 0.70 of the H/t ratio of a single wythe hollow wall. The t-value shall be the sum of the nominal thickness of the individual wythes.
  1. H = clear height or length between lateral supports.
    t = nominal wall thickness.
  2. All masonry units shall be laid in Type M, S or N mortar. Where Type N mortar is used and the wall spans in the vertical direction, the ratios shall be reduced by 10 percent.
  3. Design based on partially enclosed building.
  4. These values are based on using masonry cement mortar. If nonair-entrained Portland cement/lime mortar is used, the values in the table may be increased by 1.25. Larger H/t ratios may be used if the design is done in accordance with ACI-530.
  5. .Larger H/t ratios may be used if the design is done in accordance with ACI-530.
FIGURE R4507.1(a)
REQUIREMENTS FOR REINFORCED GROUTED MASONRY CONSTRUCTION WHERE WIND ZONES ARE 140 MPH OR GREATER


FIGURE R4507.1(b)
REQUIREMENTS FOR REINFORCED HOLLOW-UNIT MASONRY CONSTRUCTION WHERE WIND ZONES ARE 140 MPH OR GREATER

Section R4508 ROOF TIE DOWN

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.

R4508.1 Roof tie down

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Roof assemblies in the 130, 140 and 150 mph (58 m/s, 63 m/s and 67 m/s) wind zones as established in Table R301.2(1) shall have rafter or truss ties provided in accordance with either Table R4508.2 or the prescriptive requirements of Section R4508. Anchorage in the 130 mph (58 m/s) wind zone shall be continuous from the roof to the foundation wall or pier. Anchorage in the 140 and 150 mph (63 m/s and 67 m/s) wind zones shall be continuous from the roof to the footing. See Section R4504.

R4508.2 Considerations

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
For trusses, the nailing requirements from Table R4508.2 shall include the nailing requirements for both rafters and ceiling joists. As an alternative to the anchorage requirements of Tables R602.3(1) and R4508.2, the anchorage for roof members may be based on a designed connection taking into account all horizontal and vertical forces. Forces for alternative anchorage design may result from wind uplift; wind lateral on roof; wind lateral on walls to be transferred to the top plate of the wall; roof/ceiling loads; and other loads depending on the specific building design. If roof members align with the studs, the connection may be made from the roof member directly to the studs. If the connection is from the roof member to the top plate, a double top plate is required and both connections must meet the requirements of Table R4508.2. Where ceiling joists are not parallel with and connect to the roof members, the anchorage requirements for each roof member shall be increased by 110 pound (50 kg). Hip end walls and hip rafters shall be anchored in accordance with this section.

TABLE R4508.2
ROOF TIE DOWN REQUIREMENTS ALONG EXTERIOR WALLS (plf)a, b, c, d
WIND SPEED (mph) STRUCTURE WIDTH
24 feet 36 feet
'130 '240 345
140 330 470
150 430 615
For SI: 1 foot = 304.8 mm, 1 mile per hour = 0.R45 m/s.
  1. Alternate to the requirements of this table or roof not covered by this table shall be designed in accordance with the North Carolina Building Code or ICC 600 Standard for Residential Construction in High-Wind Regions.
  2. See Section 4505 for material requirements in Coastal High Hazard Areas and Ocean Hazard Areas and Ocean Hazard Areas.
  3. Roof slope 2:12 to 12:12.
  4. The uplift load requirements may be interpolated for intermediate structure widths.

R4508.3 Anchorage from roof to wall

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
One and one-half inch (38 mm) by 18 gage fabricated metal ties at 24 inches (610 mm) on center with five 8d nails at each end may be used to resist the uplift loads from the roof to the double top plate. Install one tie at each end of each rafter in 130 mph (58 m/s) and two ties at each end of each rafter in 140 mph (63 m/s) and 150 mph (67 m/s) wind zones. Truss anchorage shall be in accordance with design specifications. See Figure R4508.3.

FIGURE R4508.3
ROOF RAFTER/TRUSS ANCHORAGE

R4508.4 Anchorage using wood structural panels

AMENDMENT
This section has been amended at the state or city level. Amendments are shown in green text.
Wood structural panel sheathing may be used to resist both lateral load and uplift simultaneously. Panels shall be installed as follows:
  1. Panels may be installed parallel or perpendicular to studs.
  2. Panels shall be ⅜-inch (10 mm) minimum thickness.
  3. Nail spacing shall be 8d at 6 inches (152 mm) on center along vertical edges of panel and 12 inches (305 mm) at intermediate vertical framing.
  4. At double edge panel locations, the horizontal nail spacing shall be 8d staggered at 3 inches (76 mm) on center. See Figure R4508.4(b).
  5. Where open web trusses are installed, panel shall extend 12 inches (305 mm) beyond horizontal construction joints and shall overlap girders their full depth. Where the horizontal joint occurs over minimum 1 inch (25 mm) thick OSB or plywood or 2× rimboard, a minimum 1½ inch (38 mm) overlap is required. See Figure R4508.4(a).
  6. Panel attachment to framing shall be as illustrated in Figure R4508.4(b).
  7. Blocking shall be required at all joints if sheathing is used to resist uplift.
TABLE R4508.4
UPLIFT CAPACITY OF WOOD STRUCTURAL PANEL SHEATHING USED TO RESIST BOTH LATERAL LOAD AND UPLIFTa
VERTICAL NAIL SPACING 8D @ 6″ EDGE AND
12″ INTERMEDIATE
Alternate nail spacing at top and bottom edges 6″ 4″ 3″
Uplift capacity (plf) nails—double row 240 474 710
For SI: 1 inch = 25.4 mm.
  1. Tabulated values are for Spruce-Pine-Fir framing.
FIGURE R4508.4(a)
TWO STORY WALL SECTION—PANEL ATTACHMENT


FIGURE R4508.4(b)
PANEL ATTACHMENT TO COUNTER UPLIFT HORIZONTAL OR VERTICAL
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