South Carolina Code of Regulations
Chapter 8 - BUILDING CODES COUNCIL
Article 12 - INTERNATIONAL RESIDENTIAL CODE
Section 8-1221 - IRC R408.3 Unvented Crawl Space

Universal Citation: SC Code Regs 8-1221

Current through Register Vol. 48, No. 3, March 22, 2024

For unvented under-floor spaces, the following items shall be provided:

1. Exposed earth shall be covered with a continuous vapor retarder meeting ASTME 1745 Class A. Joints of the vapor retarder shall overlap by 6 inches (152 mm) and shall be sealed or taped. The edges of the vapor retarder shall extend not less than 6 inches (152 mm) up the stem wall and shall be attached and sealed to the stem wall or insulation.

2. One of the following is provided for the under-floor space:

2.1. Continuously operated mechanical exhaust ventilation at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7 m2) of crawl space floor area, including an air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1102.2.11 of this code.

2.2. Conditioned air supply sized to deliver at a rate equal to 1 cubic foot per minute (0.47L/s) for each 50 square feet (4.7 m2) of under-floor area, including a return air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with the S.C. Energy Codes.

2.3. Plenum in existing structures complying with Section M1601.5, if under-floor space is used as a plenum.

2.4. Dehumidification sized in accordance with the manufacturer's specifications.

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