Resources & Guides / Building Codes & Standards / ASTM & UL Standards / ASTM C1395
ASTM C1395 (Withdrawn)
Gypsum Ceiling Board - REPLACED BY ASTM C1396
⚠️ This Standard Has Been Withdrawn
ASTM C1395 has been consolidated into ASTM C1396. Use ASTM C1396, Gypsum Ceiling Board as the modern equivalent.
Historical Overview
ASTM C1395 specifically covered 1/2-inch thick gypsum board designed for use on interior ceilings with framing spaced up to 24 inches on center. The key feature was enhanced sag resistance compared to standard 1/2-inch wallboard. This standard is now withdrawn and obsolete, with requirements consolidated into ASTM C1396/C1396M covering all major types of gypsum panels, including gypsum ceiling board.
The Sag Resistance Challenge
Standard 1/2-inch drywall installed on ceiling joists or trusses spaced 24 inches apart is prone to sagging over time, especially in humid environments. Contractors would have to either use more expensive and heavier 5/8-inch Type X board or install framing at tighter 16-inch spacing, increasing material and labor costs.
Gypsum ceiling board was engineered with a higher-density core and other modifications to provide necessary sag resistance for 24-inch spacing in a lighter 1/2-inch profile - a classic example of a product engineered to solve a specific field-related problem.
Modern Specification
Correct Specification: ASTM C1396, Gypsum Ceiling Board
For residential and commercial projects using 24-inch on-center ceiling framing, specifying ASTM C1396 gypsum ceiling board is a cost-effective solution. It provides required performance without the added weight and cost of 5/8-inch board, leading to more efficient and economical design. The specific requirements for gypsum ceiling board are now found within Section 12 of ASTM C1396.