Our Slide Fold door systems enable expansive walls of glass to open up for clear unobstructed openings. Optional flush sill detailing helps create a seamless transition from interior to exterior. These door systems are popular for restaurant facades, pool enclosures, and porches, providing a spacious, wide open feel to any space.


Wood Species & Finishes

Duratherm sources all its materials by project, only from providers we know and trust. Many of our woods come from Forest Stewardship Council® (FSC- C108949) certified sources. We obtain others from sustainably-harvested plantations. Fourteen domestic and exotic wood species offer a wide range of colors, grains, and textures.

Please contact us for information about finishing options (including paint, Sikkens, clear laquer, stain, bleach stain, oil, etc.) and to discuss the use of a species not on our standard menu. We consider availability, durability, machining, and gluing characteristics to determine the feasibility of your choices.




We offer dry or wet weeped glazing compounds.

Specially developed extruded silicon gasket sets the glass by compression. Our proprietary system is long-lived, has low maintenance, and stays waterproof.

Our special silicon wet glazing compound bond to the glass for long-lived sealing. Plus our continuous extruded silicon weatherstrip runs around the frame perimeter, and the seal is not compromised by seasonal expansion and contractions of the sash and frame.




KEY (mouse over #s to view details)




Operating Assembly

G-U 925 sliding/folding hardware. Doors are top hung, with in-line rollers mounted at head of each moving panel. Heavy duty mortise construction. Multi-latchpoint locking gears. Shoot bolt assembly fully mortised into rail to provide 2-point latching at top and bottom for folding panels; hook bolt assembly fully mortised into rail to provide 3-point latching at top, bottom, and jamb for hinged panel.

Finishes: Internal operating mechanisms in zinc chromate coated steel and aluminum alloys.

Edge stile cover in clear anodized (EV-1) or dark bronze anodized (EV-5) aluminum.

External guides and tracks are clear anodized (EV-1) or dark bronze anodized (EV-5) aluminum.

Escutcheons / Lever Handles

Escutcheons and lever handles are aluminum.

Finishes: Clear anodized (EV-1) or dark bronze anodized (EV-5) aluminum.


Zinc chromate steel hinges with snap-on brown plastic covers.

Optional Hardware

Active panel independent of the folding panels can be fabricated as a tilt/turn panel. Sill detailing can be provided without threshold.

Standard Configurations

First digit = total panels. Second and third digit = folding panel groupings.
220 , 321 , 330 , 431 , 440 , 541 , 532 , 550 , 633 , 651 , 660 , 743 , 761 , 770


All glazing is per project specifications. Duratherm can accommodate most configurations and make-ups from 1/8" single glazed to a maximum of 1" security glass. Contact the factory for customized glazing and glass stop configurations.
Clear glass opening: Unit height minus 163/8". For clear glass width, contact factory.


Door Panel

Continuous extruded silicone flap gasket set in rebate in doorframe at head and jambs with doubled extruded flap silicone gasket set in rebates at bottom rail of door panels. Engaging the multi-latchpoint lever espagnolettes compresses the weather-strip to ensure a tight seal.


The minimums and maximums shown are intended as guidelines. For applications that exceed these ranges, please contact the factory for assistance.


Minimum Panel: 16”
Maximum Panel: 36"


Minimum: 34”
Maximum: 96"

ADA Compliance

Clear-opening sizing based on 32" clear width requirement.
Minimum unit width: 35 1/2"
NOTE: Standard wood threshold may not meet ADA maximum height requirements.
Consult factory with specific clearance questions

Frame Depths/Leaf Thickness

Leaf thickness: 2 11/16"
Standard frame depth*: 6 1/4"
Minimum frame depth*: 4 3/4"
Maximum frame depth: 10"

*Contact factory for frame depths less than 6 1/4".

© 2021 Duratherm Company | 720 Main Street, Vassalboro, ME 04989 | T 207.872.5558 / 800.996.5558 | F 207.872.6731