ADOPTS WITH AMENDMENTS:

International Residential Code 2015 (IRC 2015)

Part I Administrative

Part II Definitions

Part III Building Planning and Construction

Part IV Energy Conservation

Part V Mechanical

Part VI Fuel Gas

Part VII Plumbing

Part VIII Electrical

Part IX Referenced Standards

Heads up: There are no amended sections in this chapter.
This appendix contains prescriptive solutions for compliance on wind path load transfer requirements, and shall be used only within the limitations of Section AA101.2.

The prescriptive solutions specified in the following sections shall not be permitted to be used in the following conditions:

  1. Buildings and structures of any size in 110 mph or 120 mph wind zones located in a V zone as determined by community FIRMS.
  2. Two or more story buildings and structures of any size located in 120 mph wind zone with more than 20 percent exterior fenestration.
  3. Two or more story structures with a building height greater than 33 feet as measured from grade plane to the average height of the highest roof surface.
  4. Any two or more story structure or building with opening fenestration greater than 40 percent on any one wall.
The following applies to structures conventionally framed or to truss-type roofs.
Roof sheathing shall be not less than 7/16-inch finished thickness.

Roof attachment shall be accomplished with minimum 8d nails as follows:

  1. In the 4-foot perimeter edge zone along the edges: 6 inches on center (o.c.).
  2. To the intermediate supports within the 4 foot perimeter edge zone: 6 inches o.c.
  3. Along the gable end wall or rake: 4 inches o.c.
  4. All other areas: 6 inches o.c. edge; 12 inches o.c. intermediate.

All sheathing edges within the 4-foot perimeter edge zone shall be blocked with 2 × 3 minimum including the ridge line and soffit/fascia area. Provisions for ventilation air shall be maintained.

Exception: 2 × 3 intermediate blocking can be eliminated provided all sheathing is 5/8-inch nominal tongue and groove structural panels.

Ridge straps 11/4 inches × 20 gage shall be attached to each pair of opposing rafters with five 8d nails at each end into the framing member.

Exceptions:

  1. Ridge straps are not required when collar ties of nominal 1 × 6 or 2 × 4 lumber are located within the upper third of the attic space and attached to each rafter with three 10d nails
  2. Trusses without a framed ridge connection.
  3. Plywood gussets of equivalent cross section.
  4. Other engineered connections.
  5. At hips, straps shall be installed so each hip jack is connected across the hip line with at least one 8d nail into an opposite framing member.
Overhangs shall be limited to 24 inches. Ladder style rake overhangs attached to the gable end walls shall be limited to 12 inches. Cantilevered rake overhangs at gable end walls shall be limited to 24 inches.

See Section R802.11.

Exception: Roof truss to wall connection shall be designed to withstand either the load requirements of Table R802.11 or the connection loads indicated on the truss design shop drawings, whichever is greater.

Wall sheathing shall be a minimum 7/16-inch structural panel. Nailing shall be in accordance with Table R602.3 (1) and the following:

  1. At the top plate or plates, the sheathing shall extend from the top of the top plate to a minimum of 16 inches beyond the stud-to-bottom of the top plate connection. A minimum of 4 nails shall be used at each stud fastening, and edge-nailed to each plate at 6 inches o.c..

    Alternate: prefabricated and pre-engineered connection straps approved by the Building Official.

  2. If the studs are not continuous to the foundation plate such as at an intermediate floor, the wall sheathing shall be continuous and uninterrupted for a distance of 16 inches beyond from top of bottom wall plate to 16 inches beyond bottom of bottom wall top plate below, with a minimum of 4 nails at each stud, and field-nailed at 6 inches o.c. to floor joist header framing.

    Alternate: Prefabricated and pre-engineered connection anchors or fasteners approved by the Building Official.

  3. At the bottom of the wall assembly to the foundation sill plate, the wall sheathing shall be continuous from a point 16 inches above the top of the bottom wall plate to the bottom of the foundation sill, with a minimum of 4 nails at each stud, 6-inch field nailed and edge nailed to the foundation sill plate at 6 inches o.c.

    Alternate: Prefabricated pre-engineered connection anchors or fasteners approved by the Building Official.

A 4-foot segment of wall sheathing shall be designated as a shear wall at each corner of the structure at each floor, and no more than 24 feet apart along a wall length. The following additional requirements apply:

  1. No openings are permitted within this 4-foot section.

    Exception: Window openings are allowed no closer than 2 feet to corner providing the length of that shear panel is increased to 8 feet.

  2. All edges shall be blocked and nailed at 6 inches o.c., and field-nailed at 6 inches o.c.
  3. Studs shall be doubled at each end of the shear wall panel.

First-story shear walls shall be connected to the foundation below with connection anchoring capable of 3,500-pound hold-down capacity, in addition to conventional foundation anchor bolt requirements in the remainder of the panel. The hold downs shall be fastened to each end of the shear wall at the double stud.

Exceptions:

  1. Shear wall hold-downs shall not be required in Wind Zones I and II (100 mph or 110 mph).
  2. Shear wall anchors shall not be required provided 1/2-inch anchor bolts at 48 inches o.c. maximum are installed with the top of the bolts anchored through the floor system to the bottom plate of the exterior wall frame for the entire foundation perimeter.

Anchor bolts shall be installed in accordance with Section R403.1.6 and the following:

1- & 2-story buildings 1/2" @ 48" o.c. or 5/8" @ 72" o.c.
3-story building 1/2" @ 24" o.c. or 5/8" @ 36" o.c.

Alternate: Prefabricated and pre-engineered connections in design and quantity sufficient to equal strength of anchor bolt specification above.

Exception. See Exception 2 to AA203.2.1.

For Wind Zones 2 (110 mph) and 3 (120 mph) the following conditions apply:

Exterior bearing and nonbearing walls greater than 10 feet in height shall be 2 × 6 @ 16 inches o.c. minimum.

Walls with a total height greater than 10 feet shall be permitted to use 2 × 4 @ 16 inches o.c. providing the wall is limited to 10 feet in length and the individual studs are not greater than 9 feet in length.

In Wind Zone 3 (120 mph), garage doors shall be limited to 9 × 8 feet nominal.
Deviations from the above prescriptive requirements shall only be permitted if stamped calculations and drawings are provided by a Rhode Island registered professional engineer for alternative connections.
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