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M-BLOC® Impact Resistant Type X Gypsum Board

M-Bloc® IR Type X interior gypsum panels were designed and tested to not only provide exceptional resistance to mold and moisture, but superior resistance to impact penetration, abrasion, abuse and indention when compared to traditional wallboard. This Type X panel consist of an impact, abuse defiant core encased in heavy abrasion, mold and moisture resistant blue face paper and brown back paper manufactured from 100% recycled paper, with a fiberglass mesh fabric embedded into the core adjacent to the back of the panel to provide additional impact and penetration resistance. At an independent laboratory accredited in accordance with ISO 17025-2005, M-Bloc panels have been tested to the industry’s most rigorous standard achieving the best possible results per ASTM D3273, scoring a perfect 10 thus minimizing the risk of mold and mildew growth.

Basic Uses

M-Bloc IR Type X interior gypsum panels are recommended for commercial and institutional construction where greater resistance to impact, abrasion, abuse and indentation are required. These UL classified panels are allowed for use in any fire rated design where American Gypsum’s 5/8” Type X wallboard is approved. Additionally M-Bloc IR Type X panels can be used as a base for the adhesive application of ceramic or plastic tile in limited wet areas, e.g., bathrooms, kitchens, laundry, and utility rooms.

  • Abrasion Resistance: Level 3
  • Indentation Resistance: Level 1
  • Soft Body Impact Resistance: Level 3
  • Hard Body Impact Resistance: Level 3


Shaft liner gypsum wallboard has attained the GREENGUARD Indoor Air Quality Certified status and GREENGUARD Children & Schools Indoor Air Quality Certified status. For more information click on the link at right.

Product Data


ThicknessWidthsLengthsEdge Types
5/8" (15.9mm) 4' (1219mm) 8' (2438mm) Tapered
5/8" (15.9mm) 4' (1219mm) 10' (3048mm) Tapered
5/8" (15.9mm) 4' (1219mm) 12' (3658mm) Tapered

Special lengths or edges may be available on special order. Consult your American Gypsum sales representative for details.

Thermal Resistance “R” Value 5/8” = 0.61

Technical Data

Storage and Handling

Installation - M-Bloc IR Type X shall be installed in accordance with the recent editions of “Application and Finishing of Gypsum Panel Products” (GA-216) and or “Standard Specification for Application and Finishing of Gypsum Board” (ASTM C 840).

The building temperature shall be maintained at not less than 50ºF (10ºC) for adhesive application of gypsum board, during joint treatment, texturing, and decoration. When a temporary heat source is used the temperature shall not be more than 95°F (35°) in any given room or area. Adequate and continuous ventilation shall be provided in the working area during the installation and the drying or curing period.

The listed impact penetration/abrasion/abuse/indention ratings apply to walls constructed with M-Bloc IR Type X gypsum wallboard installed vertically to minimum 20 gauge framing members spaced a maximum of 16" o/c. 

The design professional has the ultimate responsibility for location of control joints.

Decoration - The design professional, contractor and or owner shall review “Recommended Levels of Gypsum Board Finish” (GA-214), in order to specify the proper level of drywall finishing needed to assure the desired results. For best painting results, all surfaces, including joint compound, should be clean, dust-free and not glossy. To equalize the porosities between the face paper and joint compound and improve fastener and joint concealment, the surface shall be primed and sealed with a full-bodied high solids drywall primer before texturing or final decoration. The selection of the proper paint to give the specified or desired finished characteristics is the responsibility of the design professional, contractor and or owner.

Applicable Standards

Mold Resistance

Score of 10 (ASTM D 3273)


ASTM C 1396

Federal Specification - SS-L-30D Type III Grade X

Abrasion Resistance

Level 3

Indentation Resistance

Level 1

Soft Body Impact Resistance

Level 3

Hard Body Impact Resistance

Level 3

Surface Burning Characteristics


Flame Spread - 0

Smoke Developed - 0

LEED Contributions

Our products can contribute to the following credits within the Materials and Resources (MR) category.

  • LEED MR Credit 2: Construction Waste Management
  • LEED MR Credit 4: Recycled Content
  • LEED MR Credit 5: Regional Materials

Our products can contribute to the following credit within the Indoor Environmental Quality (IEQ) category.

  • LEED IEQ Credit 4.6: Low-Emitting Materials - Ceiling and Wall Systems (SCHOOLS ONLY)

To learn more please click the LEED link at right.

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