Helping keep tenants and structures protected from mold and moisture

exteriorgypsumsheathing

1. Bathroom/Powder Room
Mold/Moisture-Resistant Gypsum Panels are ideal for areas prone to humidity and moisture
Physical Description
Mold/Moisture-Resistant Gypsum Panels are designed around an improved mold- and moisture-resistant core covered by either treated moisture- and mold-resistant paper facers or naturally mold-resistant fiberglass mats. The long edges of each panel are wrapped by the facer material and are typically tapered to improve joint treatment while the product’s short edges are cut square. Mold/Moisture-Resistant Gypsum Panels are produced in 1/2” (12.7 mm) or 5/8” (15.9 mm) thicknesses, widths of 48” (1220 mm) or 54” (1372 mm) and lengths from 8’ (2440 mm) to 16’ (4880 mm). The product is available in three core formulations – a 1/2” standard version, a 1/2” Type C option and a more common fire-resistant 5/8” Type X choice. The applicable product standard for mold-resistant gypsum board is ASTM C1396.

Advantages and Benefits
Mold/Moisture-Resistant Gypsum Panels were introduced to provide better protection against the threat of moisture damage than standard drywall, but it can be installed and finished just as easily. In addition, Mold/Moisture-Resistant Gypsum Panels offer a number of other benefits related to the appearance, operation and construction of multi-family structures.

o Moisture Protection – The first priority of Mold/Moisture-Resistant Gypsum Panels is to repel both liquid and vapor forms of moisture. The more moisture they prevent from being absorbed through their surface and retained either within the board or the wall cavity, the better they protect the entire wall or ceiling assembly from a deterioration of materials or performance. The maximum water absorption value for this product is 5% of board weight. Refer to GA-235 Gypsum Board Typical Mechanical And Physical Properties.

o Mold Resistance – Mold/Moisture-Resistant Gypsum Panels are formulated with anti-microbial properties in their core as well as their facers to resist the development of mold and mildew better than traditional gypsum panel products. Used in conjunction with good design, handling, and construction practices, this can help extend the life and appearance of interior surfaces, reduce the factors favoring mold formation and provide a pre-emptive strategy to minimize health risks to occupants and visitors in multi-family units. Refer to GA-238 Guidelines For Prevention Of Mold Growth On Gypsum Board.

o Fire Resistance – Mold/Moisture-Resistant Gypsum Panels are manufactured with a standard gypsum core as well as enhanced fire-resistive Type C and Type X core variations. These fire-resistant product options can be used in any fire-rated assembly where the corresponding UL-classified Type C or Type X gypsum panel is approved to help design structures engineered for improved fire protection, reduced flame spread and less smoke generation compared to traditional drywall. Refer to GA-600 Fire Resistance and Sound Control Design Manual.

o Construction Efficiency – The same handling, cutting, fastening and finishing techniques that apply to standard gypsum panel products apply to Mold/Moisture-Resistant Gypsum Panels as well. Their cost efficiency and versatility throughout the construction process can help keep you on schedule and on budget on both new construction and remodeling jobs.

o Noise Attenuation – Most building codes recommend a minimum standard STC of 45 for wall assemblies between occupied units in multi-tenant structures to provide a comfortable level of noise protection. Interior walls and ceilings constructed according to assemblies documented in GA-600 Gypsum Fire Resistance and Sound Control Design Manual provide an effective mechanism to achieve improved acoustical performance objectives. Mold/Moisture-Resistant Gypsum Board can be used in any assembly where the corresponding UL-classified 1/2” Type C or 5/8” Type X drywall is approved. more

Limitations
To achieve the design and performance objectives specified for the walls and ceilings of your multi-family project, a number of important limitations should be followed to ensure success. These recommendations are intended to provide general information only about considerations that are common in this category of special performance gypsum products:

o Mold/Moisture-Resistant Gypsum Panels are intended for interior use only
o Mold/Moisture-Resistant Gypsum Panels are nonstructural and are not designed to be a fastener base for mounting other materials to walls or ceilings
o avoid exposure to prolonged temperatures exceeding 125°
o wall and floor cavities must be dry before closing-up or applying interior finishes
o not intended for constant exposure to moisture, ponding or cascading water
o to prevent mold and mildew growth, avoid exposure to water during handling, storage and installation and after installation is complete
o not designed to be used as a substrate for tile applications

Refer to GA-216 Application And Finishing Of Gypsum Panel Products.

Products vary by brand. For more specific limitations related to the gypsum panel you are considering, consult with the product’s manufacturer.

Frequently Asked Questions
Below are answers to typical questions our technical experts address on a routine basis. These answers may provide additional information you are seeking as well. To submit an inquiry of your own, click here.

1. I understand that even Mold/Moisture Resistant Gypsum Panels should not be used in so-called “wet areas.” Can you explain where this product can and cannot be used?

Mold/Moisture Resistant Gypsum Panels are excellent for use in high humidity areas and even where an occasional splash of water is expected. Appropriate areas include powder rooms, adjacent to showers or tubs, behind counter areas/base cabinetry where plumbing fixtures are located, and in laundry rooms, mud rooms, etc.. However, neither the model codes nor the Tile Council of North America’s (TCNA) Handbook allow for the use of these boards behind the tile in the shower or tub area or as a base under the pan or around a swimming pool or sauna. For acceptable materials in wet areas, consult the local code or the TCNA.

For Further Information
To read more about the testing procedures to evaluate the moisture-resistant characteristics of the core and facers of a gypsum panel product, refer to ASTM C473.

To read more about the testing procedures to evaluate the mold-resistant properties of the core and facers of a gypsum panel product, refer to ASTM D6329.