ADOPTS WITH AMENDMENTS:

International Existing Building Code 2018 (IEBC 2018)

Heads up: There are no amended sections in this chapter.
This chapter provides prescriptive methods for partial structural retrofit of an existing building to increase its resistance to wind loads. It is intended for voluntary use where the ultimate design wind speed, Vult, determined in accordance with Figure 1609.3(1) of the Internationat Building Code exceeds 130 mph (58 m/s) and for reference by mitigation programs. The provisions of this chapter do not necessarily satisfy requirements for new construction. Unless specifically cited, the provisions of this chapter do not necessarily satisfy requirements for structural improvements triggered by addition, alteration, repair, change of occupancy, building relocation or other circumstances.

The provisions of this chapter are applicable only to buildings that meet either of the following eligibility requirements:

  1. Buildings assigned to Risk Category I or II in accordance with International Building Code Table 1604.5.
  2. Buildings within the scope of the International Residential Code.
For one- and two-family dwellings, fastening shall be in accordance with Section C202.1.1 or C202.1.2 as appropriate for the existing construction. The diameter of 8d nails shall be not less than 0.131 inch (3 mm) and the length shall be not less than 21/4 inches (57 mm) to qualify for the provisions of this section for existing nails regardless of head shape or head diameter.
Roof decking consisting of sawn lumber or wood planks up to 12 inches (30 cm) wide and secured with not fewer than two nails (minimum size 8d) to each roof framing member it crosses shall be deemed to be sufficiently connected. Sawn lumber or wood plank decking secured with smaller fasteners than 8d nails or with fewer than two nails (minimum size 8d) to each framing member it crosses shall be deemed sufficiently connected if fasteners are added such that two clipped head, round head or ring shank nails (minimum size 8d) are in place on each framing member the nail crosses.

For roof decking consisting of wood structural panels, fasteners and spacings required in Table C202.1.2 shall be deemed to comply with the requirements of Section 707.3 of the International Existing Building Code.

Supplemental fasteners as required by Table C202.1.2 shall be 8d ring shank nails with round heads and the following minimum dimensions:

  1. 0.113-inch-nominal (3 mm) shank diameter.
  2. Ring diameter not less than 0.012 inch (0.3 mm) greater than shank diameter.
  3. 16 to 20 rings per inch.
  4. A minimum 0.280-inch (7 mm) full round head diameter.
  5. Ring shank to extend not less than 11/2 inches (38 mm) from the tip of the nail.
  6. Minimum 21/4-inch (57 mm) nail length.

[BS] TABLE C202.1.2

SUPPLEMENT FASTENERS AT PANEL EDGES AND INTERMEDIATE FRAMING

EXISTING FASTENERS EXISTING FASTENER
SPACING (EDGE OR
INTERMEDIATE SUPPORTS)
MAXIMUM SUPPLEMENTAL
FASTENER SPACING
FOR 130 MPH < Vult 140 MPH
MAXIMUM SUPPLEMENTAL
FASTENER SPACING FOR
INTERIOR ZONEc
LOCATIONS FOR MPH
Vult > 140 MPH AND
EDGE ZONES NOT COVERED
BY THE COLUMN
TO THE RIGHT
EDGE ZONEd FOR Vult > 160 MPH
AND EXPOSURE C, OR
Vult > 180 MPH AND
EXPOSURE B
Staples or 6d Any 6" o.c.b 6" o.c.b 4" o.c.b at panel edges and 4" o.c.b at intermediate supports
8d clipped head or round head smooth shank 6" o.c. or less None necessary None necessary along edges of panels but 6" o.c.b at intermediate supports of panel 4" o.c.a at panel edges and 4" o.c.a at intermediate supports
8d clipped head or round head ring shank 6" o.c. or less None necessary None necessary 4" o.c.a at panel edges and 4" o.c.a at intermediate supports
8d clipped head or round head smooth shank Greater than 6" o.c. 6" o.c.a 6" o.c.a along panel edges and 6" o.c.b at intermediate supports of panel 4" o.c.a at panel edges and 4" o.c.a at intermediate supports
8d clipped head or round head ring shank Greater than 6" o.c. 6" o.c.a 6" o.c.a 4" o.c.a at panel edges and 4" o.c.a at intermediate supports

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

  1. Maximum spacing determined based on existing fasteners and supplemental fasteners.
  2. Maximum spacing determined based on supplemental fasteners only.
  3. Interior zone = sheathing that is not located within 4 feet of the perimeter edge of the roof or within 4 feet of each side of a ridge.
  4. Edge zone = sheathing that is located within 4 feet of the perimeter edge of the roof and within 4 feet of each side of a ridge.

IBC—18

<span class="italic">International Building Code<sup>®</sup></span>

C101.3, C103.2, C201.1, C201.2

IEBC—18

<span class="italic">International Existing Building Code<sup>®</sup></span>

C202.1.2

IRC—18

<span class="italic">International Residential Code<sup>®</sup></span>

C101.2, C101.3, C103.2, C201.2

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