Xtend Mull Profile and Mulled-Frame Cross-Sections
Cross-sections for joining two Xtend 4-vent units side by side. Shows the integrated mull post, how units A and B connect, flange treatment, and sealant placement for a weather-tight mulled assembly.
What this document covers
This drawing shows the mulled-frame cross-sections with track for two Xtend units joined together. Unit A carries an integrated mull post on its right side; Unit B's left side overlaps and fastens to it.
- Left and right side profiles for both units (A and B)
- Integrated mull post on the right side of Unit A
- How Unit B's clipped top and bottom flanges butt to Unit A
- Mounting flange detail and pre-drilled hole spacing
- Sealant placement, including the mull flange and top butt joint
Key specifications at a glance
- Window width: frame opening less 1/4"
- Extrusion: 16 ga powder-coated aluminum, approx. 1/16" thick
- Mounting flange: exposed, flat-head color-matched screws; trim may be added over the flange
- Flange pre-drilling: 1/4" holes centered 5/16" from edge
- Sash track: left side track is deeper for sash retention springs
- Scale: 1:2
Installation notes
Sealant: apply behind all side and top flanges including the mull flange of Unit B, and at the top butt joint between Units A and B; window tape is recommended. Fastening: install flat-head screws at the top and bottom of the Unit A mull flanges using the pre-drilled holes; self-tapping screws are provided. Aluminum framing: notify Porch Windows Direct if using aluminum framing — color-matched self-tapping hex-head screws will be provided. Note: windows under 60" in height use 3-vent panels utilizing the 3 outer tracks.
