Mullion Mate Partition Gap Closures
Mullion Mate is an adjustable partition closure that creates the perfect transition between window mullions, windows, and partition walls.
Mullion Mate® is an adjustable partition closure that creates a seamless transition between window mullions (curtain walls), windows, and partition walls. Aesthetically pleasing, these spring-loaded partition closures bridge the gap to fit a variety of openings and provide excellent noise reduction up to 60 STC. Finished to match mullions, factory cut to length, and arriving to the jobsite pre-assembled, Mullion Mate’s ease of installation creates the solution to an everyday problem.
Designed to Accommodate Lateral Movement up to 1-15/16″
Lateral movement in buildings is caused by SEISMIC, THERMAL, and WIND SWAY activity. Gordon’s Mullion Mate products allow lateral movement, while providing a termination of a wall at the curtain wall and an acoustical barrier.

Design Attributes
- For vertical junctions between partition walls and window mullions
- Finished to match mullions
- Clear, medium, or dark bronze anodized, and Champagne
- Field paintable finish
- Powder coated in standard or custom colors (AAMA2604/AAMA2605)
- Custom Finishes available upon request
- Factory spring loaded to fit a variety of opening sizes
- Pre-assembled for ease of installation
- Factory cut to desired height, maximum 192″
- Optional Mullion Mate end cap to finish partition walls
Mullion Mate Profiles
Series 60
- Closes Gaps from 4” up to 8-1/2”
- Double Mullion Mate® design surrounds the window mullion, increasing STC up to 60.
- Patent Pending

Series 60 Sizes
Mullion Mate 4 – 4″ minimum to 5-7/16″ maximum opening
Mullion Mate 5.5 – 5-1/2″ minimum to 6-15/16″ maximum opening
Mullion Mate 7 – 7″ minimum to 8-1/2″ maximum opening
Series 40
- Closes Gaps from 2” up to 14”
- Provides up to 56 STC

Series 40 Sizes
Mullion Mate 2 – 2″ minimum to 2-15/16″ maximum opening
Mullion Mate 3 – 3″ minimum to 3-15/16″ maximum opening
Mullion Mate 4 – 4″ minimum to 4-15/16″ maximum opening
Mullion Mate 5 – 5″ minimum to 6-15/16″ maximum opening
Mullion Mate 7 – 7″ minimum to 8-15/16″ maximum opening
Mullion Mate 9 – 9″ minimum to 14″ maximum opening
Series 30
- Closes Gaps from 2” up to 14”
- Provides up to 37 STC

Series 30 Sizes
Mullion Mate 2 – 2″ minimum to 2-15/16″ maximum opening
Mullion Mate 3 – 3″ minimum to 3-15/16″ maximum opening
Mullion Mate 4 – 4″ minimum to 4-15/16″ maximum opening
Mullion Mate 5 – 5″ minimum to 6-15/16″ maximum opening
Mullion Mate 7 – 7″ minimum to 8-15/16″ maximum opening
Mullion Mate 9 – 9″ minimum to 14″ maximum opening
Series 20
- Closes Small Gaps from 1” up to 2”
- Patent Pending

Series 20 Sizes
Mullion Mate 1 – 1″ minimum to 1-7/16″ maximum opening
Mullion Mate 1.5 – 1-1/2″ minimum to 2″ maximum opening
Partition Wall End Caps


Features & Benefits

Installation Options

Wall-to-Mullion

Wall-to-Glass

Wall-to-Glass
(Field Notch)
Videos
Finish Options
AAMA 2604 Powder Coat Finishes Download PDF
AAMA 2605 Powder Coat Finishes Download PDF
Antimicrobial Finishes
Green By Design
- Products contribute to LEED® certification
- In-House Finishes
- Biodegradable pre-treatment powder coat (no phosphates)
- No hazardous waste
- No VOC’s
- No Heavy Metals
- Reference our sustainability page for more information.
Product Data
Mullion Mate Series 60 Consolidated Set
Mullion Mate Series 40 Consolidated Set
Mullion Mate Series 30 Consolidated Set
Mullion Mate Series 20 Consolidated Set
Mullion Mate End Cap Details
Mullion Mate Series 60 Specifications
Mullion Mate Series 40 Specifications
Mullion Mate Series 30 Specifications
Mullion Mate Series 20 Specifications
Gap Closures for Fire Rated Walls
White Paper (STC Acoustics)
Technical Data (Seismic)