Muddable J-Bead

Used to finish drywall edges when dissimilar materials and door and window encasements meet gypsum

Muddable J-Bead is designed to cover raw edges of drywall when butting up to other materials such as masonry, glass, door frames and window trims.


Raised shoulder and extensive perforations along flange ensure excellent finishing compound adhesion and flush finish. Moisture- and  thermal-resistant properties of rigid vinyl trims make for ideal use around bathtubs, showers, windows and skylights. Rust proof and dent resistant. Easy to cut and install. Available in 1/2" and 5/8" depths.

  • Moisture and dent resistant.
  • Raised shoulder and perforations enhance compound adhesion.
  • Produces finished edges at panel terminations.

Step 1:
Make sure the surface of the drywall is clean and smooth. Avoid using the tapered edge of the drywall board for this application. Measure and cut the Muddable J-Bead to length. Subtract ½” for vertical applications. Dry fit the bead to ensure the optimum fit.

Step 2:
Position the mud leg of the Muddable J-Bead so that it is facing the room’s interior. Slip the J-Bead over the edge of the drywall until both edges meet.

Step 3:
Install the drywall equipped with the J-Bead using screws as normal.

Step 4:
Staple the Muddable J-Bead every 6”- 8” with ½” staples while applying pressure by hand to keep the bead tight to the drywall surface.

Step 5:
Using a 6” taping knife, apply a coat of joint compound to the surface of the J-Bead’s mud leg. The use lightweight compound or setting-type compound in this step will reduce shrinkage and speed up the drying time. Let this dry completely, for several hours or overnight.  

Step 6:
Using an 8” taping knife, apply the final coat of joint compound. Feather the compound beyond the previous coat. The use of all-purpose compound or topping compound will make for a more durable finish. Let this dry completely, for several hours or overnight. 

Step 7:
Sand lightly with 120 grit sandpaper to finish.

Watch how the muddable J-Bead is installed in a Armstrong® module perimeter acoustical drywall system:


ASTM & Code Standards

  • ASTM C1047 - Standard Specification for Accessories for Gypsum Wallboard and Gypsum Veneer Base
  • ASTM D3678 - Standard Specification for Rigid Poly Vinyl Chloride (PVC) Interior Profile Extrusions
  • Installation: ASTM C840 - Standard Specification for Application and Finishing of Gypsum Board
  • SDS & Product Certification Information


All stored materials shall be kept dry.  Materials shall be stacked off the ground, supported on a level platform, and protected from the weather.


PRoduct submittal SHeets

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Product Code Description
MJB Muddable J-Bead

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