FAQ Knowledge Articles

Integrity Double Hung (ITDH) jamb extension is not factory installed at the same location as a IRect DG (polygon) unit so the ITDH units need a field fix for them to align.

Manufacturing places the jamb extension at different sill locations on the Wood-Ultrex ITDH and a IRECT DG.  So, it can be a challenge to align trim at the sill.

To solve this issue, Integrity recommends ordering the jamb extension loose by part numbers on the ITDH unit(s).
If units are already in the field, re-order new jamb extension pieces to replace them because the existing ones will be too short.  Also order W9295 Structural Mull Tie for the bottom of the ITDH unit(s).

The W9295 structural mull tie is added in the field at the bottom of the sill on the ITDH unit(s).  The sill jamb extension is then placed on the W9295 Structural mull tie at the sill.  Now the sill trim will align across the units.

Note:  If the ITDH was ordered with 6 9/16" jamb extension factory applied.  This structural mull tie (PN 31510984/39210984) will replace the sill filler blocks, making the unit slightly taller.   One will need longer 6 9/16" jamb extension pieces for the jambs.
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For more information, see:
What is Jamb extension?
For Integrity, what jamb extensions are available?
Are Integrity jamb extensions able to be shipped loose?
What kind of mulling does Marvin offer?
Jamb Extension Field Applied Installation Instruction