AMSCO Windows

Sound Window Mull Process

Sound Window Mull Process
Process:
To define the process for adequately mulling sound windows together.
Definitions:
Mulling: the attachment of two or more frames to each other.
Procedure:
  1. Compare information located on Frame Barcodes to that provided in the mull cutout. Determine mull configuration as specified in the mull cutout drawing.
  2. Using the nail fin ripper, remove the nail fin across the base of the frame edge being mulled.
    3. Removing Nail Fin
  3. Cut a notch in the accessory groove at the corners where the mull bead passes through the edge of the frame.
    4. Acessory Grove
  4. With a 9/64” drill bit, Drill the rebar 3” from each end, leaving no space greater than 12” between holes.
    5. Drilling Rebar
  5. On over/under mull configurations, using a 3/8” bit, drill through the exterior wall of the head of the lower frame, 3” – 5” in from each jamb on the edge being mulled.
    6. Drilling Weeps over/under
  6. Apply a bead of silicone where the primary and secondary frames meet, then tool the silicone into the gap.
    7. Silicone between Primary and Secondary Tooling Silicone Between Primary and Secondary
  7. Center the reinforcement on the head of the bottom window, aligning the uppermost lip with the edge where the primary and secondary frames meet.
  8. Attach the reinforcement to the frame through the drilled holes using 8 X 3/4” PFH wood screws.
    9. Attaching Mull Rebar
  9. Apply a bead of silicone to the 2nd and 4th channels of the mull rebar.
    1. Apply enough silicone to fill the channels and create a 1/8” crowning.
  10. Lay the windows on the table with the interior facing up. Place 3 1/2” pieces of backer rod between the windows 6” from each end and no more than 24” apart, pushed against the rebar.
    11. Backer rod
  11. Fill each accessory groove with clear silicone.
    12. Epoxy over backer rod
  12. Align one of the mull strips with the edge of the frame, and using a mallet, pound the mull strip into the grooves along the entire width. Cover the area with a rag to prevent the silicone from splattering on the frame.
    13. Mull Strip
  13. Using alcohol, clean all excess silicone from the visible surfaces of the window.
  14. Flip the window so that the exterior is facing up.
  15. Fill both accessory grooves with silicone, like in the previous step, and pound the mull strip flush with the frame edges.
  16. Using alcohol, clean all excess silicone from the frame’s face.
  17. Repeat the following steps for both ends of the window.
  18. Place a small amount of silicone in the gap, followed by a 4 ½” piece of backer rod.
    19. Packing with Backer rod
  19. Fill the gap between the windows with silicone and tool it in until it is smooth and flush with the frame edge.
    20. Packing with Silicone
  20. With epoxy mull glue, apply a 6” drip cap piece with a “DO NOT REMOVE” sticker on it over the exterior portion of the mull joint. Attach a metal installation strap centered over the windows resting against the nail fin using (6) 7 X ½” screws.
    21. Metal Plate
Skip steps 21-26 for windows mulled side by side.
  1. Repeat the following steps for both ends of the windows.
  2. Place the weep punch jig on the frame using the vertical accessory groove as a guide.
  3. Make sure that the punch is oriented so that the bottom of the top window gets punched.
  4. Using a mallet, firmly strike the plunger, punching a weep hole through the mull strip and the first channel of the frame.
    5. Weep Punch
  5. Use the depth gauge to check for the proper depth. If the gauge does not bottom out against the frame, repeat step 24.
  6. For support, attach a wood 2” X 4” to the inside of the sill through the nail fin and a wood 1” X 2” to the exterior through the nail fin.
  7. Using alcohol, clean all excess silicone from the frame.





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