Chapter 25 — GYPSUM BOARD, GYPSUM PANEL PRODUCTS AND PLASTER

(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- CG	SFM	HCD			DSA			OSHPD						BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
Adopting agency	BSC	BSC- CG	SFM	1	2	1/AC	AC	SS	SS/CC	1	1R	2	3	4	5	5	5	5	5	5	5	5	5
Adopt entire chapter	X			X	X								X
Adopt entire chapter as amended (amended sections listed below)								X	X	X	X	X		X	X
Adopt only those sections that are listed below																				X
Chapter / Section
2501.1.1								X	X	X	X	X		X	X
2501.1.2								X	X	X	X	X		X	X
2501.1.3								X	X	X	X	X		X	X
2503.2								X	X	X	X	X		X	X
2503.2, Exception												X
2504.2								X	X	X	X	X		X	X
2504.2.1, Exception												X
2505.3								X	X	X	X	X		X	X
2505.3, Exception												X
2507.3								X	X	X	X	X		X	X
2507.3, Exception												X
2508.6.6								X	X	X	X	X		X	X
2508.6.6, Exception												X
2510.6.3																				X
2514.1_ Exception_								X		X	X	X		X	X

The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.

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CHAPTER 25

GYPSUM BOARD, GYPSUM PANEL PRODUCTS AND PLASTER

User notes:

About this chapter: Chapter 25 contains the provisions and referenced standards that regulate the design, construction and quality of gypsum board, gypsum panel products and plaster and, in addition, addresses reinforced gypsum concrete. These materials are some of the most commonly used interior and exterior finish materials in the building industry. This chapter primarily addresses quality-control-related issues with regard to material specifications and installation requirements. Most products are manufactured in accordance with industry stan- dards. The building official or inspector needs to verify that the appropriate product is used and properly installed for the intended use and location. Proper design and installation of these materials are necessary to provide weather resistance and required fire protection for both structural and nonstructural building components.

Code development reminder: Code change proposals to this chapter will be considered by the IBC—Structural Code Development Commit- tee during the 2022 (Group B) Code Development Cycle.

2510.6 Water-resistive barriers.¶

Water-resistive barriers shall be installed as required in Section 1403.2 and, where applied over wood-based sheathing, shall comply with Section 2510.6.1 or 2510.6.2.

2510.6.1 Dry climates. One of the following shall apply for dry (B) climate zones:

The water-resistive barrier shall be two layers of 10-minute Grade D paper or have a water resistance equal to or greater than two layers of waterresistive barrier complying with ASTM E2556, Type I. The individual layers shall be installed independently such that each layer provides a separate continuous plane and any flashing, installed in accordance with Section 1404.4 and intended to drain to the water-resistive barrier, is directed between the layers.
The water-resistive barrier shall be 60-minute Grade D paper or have a water resistance equal to or greater than one layer of water-resistive barrier complying with ASTM E2556, Type II. The water-resistive barrier shall be separated from the stucco by a layer of foam plastic insulating sheathing or other nonwater absorbing layer, or a drainage space.

2510.6.2 Moist or marine climates. In moist (A) or marine (C) climate zones, water-resistive barrier shall comply with one of the following:

In addition to complying with Item 1 or 2 of Section 2510.6.1, a space or drainage material not less than 3/16 inch (4.8 mm) in depth shall be applied to the exterior side of the water-resistive barrier.
In addition to complying with Item 2 of Section 2510.6.1, drainage on the exterior side of the waterresistive barrier shall have a minimum drainage efficiency of 90 percent as measured in accordance with ASTM E2273 or Annex A2 of ASTM E2925.

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ceiling surfaces require more than the maximum thickness permitted in ASTM C842 or ASTM C926, metal lath or wire fabric lath shall be installed on such surfaces before plastering.

2511.5 Wet areas.¶

Showers and public toilet walls shall conform to Sections 1210.2 and 1210.3. Where wood frame walls and partitions are covered on the interior with cement plaster or tile of similar material and are subject to water splash, the framing shall be protected with an approved moisture barrier.