California Green Building Code (CALGreen) – Moisture control

Moisture control is protecting the building exterior from water intrusion like wind driven rains and other elements. Controlling moisture is important to protect occupants from adverse health effects and to protect the building, its mechanical systems and its contents from physical or chemical damage.

CALGreen Code Section 5.407.2: Moisture control.

Employ moisture control measures by the following methods.

CALGreen Code Section 5.407.2.1: Sprinklers.

Design and maintain landscape irrigation systems to prevent spray on structures.

CALGreen Code Section 5.407.2.2: Entries and openings.

Design exterior entries and/or openings subject to foot traffic or wind-driven rain to prevent water intrusion into buildings as follows:

CALGreen Code Section 5.407.2.2.1: Exterior door protection.

Primary exterior entries shall be covered to prevent water intrusion by using nonabsorbent floor and wall finishes within at least 2 feet around and perpendicular to such openings plus at least one of the following:

1. An installed awning at least 4 feet in depth.

2. The door is protected by a roof overhang at least 4 feet in depth.

3. The door is recessed at least 4 feet.

4. Other methods which provide equivalent protection.

CALGreen Code Section 5.407.2.2.2: Flashing.

Install flashings integrated with a drainage plane.


The intent of this code requirement is to minimize the amount of moisture entering and remaining within wall assemblies of the building, to protect from water intrusion at exterior entries and openings from wind-driven rain, and to minimize water damage at exterior walls from possible effects of irrigation sprinkler systems.

Compliance Method:

Design irrigation systems to prevent spray on structures by specifying sprinkler heads that are adjacent to or near exterior walls to have a maximum degree head rotation or spray pattern or shielding that ensures protection of the building exterior.

1. Specify nonabsorbent flooring material at the interior landing surface a minimum of 2 feet in the direction of travel and at wall finishes adjacent to the door opening on the sides and above the door.

Note: If 2 feet is not available above the opening, wall finishes may terminate at the ceiling.

2. Show compliance with one of the four listed requirements for door protection.

3. Install flashings, integrated with a drainage plane.


Show on the construction documents that landscape or irrigation sprinkler design and features meet the requirements.


Plan intake: The plan reviewer should confirm on the construction documents that the irrigation sprinkler design, features, and methods at entries and openings are included. Also, verify that flashings are integrated with the drainage plane.

On-site enforcement: The inspector should verify the irrigation sprinkler operations and that entries, openings features and flashing/drainage planes are installed in accordance with the approved construction documents.

(Excerpted from ‘Guide to the 2019 California Green Building Standards Code Nonresidential’ – Chapter 5)

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