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Residential Bi-Fold Windows
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The Altherm bi-fold system offers formats that can stack to one or both sides. Corners are square-cut for optimum strength and aesthetics and the track is within the frame for direct window support.

A wide range of configurations are available including 'lay-back' arrangements in 2-panel formats that allow the bi-folds to swing back against adjoining walls for the clearing of decks. A brush seal at the frame head protects against the entry of rainwater.

Key Features
  • For mainstream residential use
  • Ideal for wide openings
  • A wide range of configurations available
  • Flat-face frame for clean aesthetics
  • An in-frame track provide optimum panel support
  • For uncluttered decks a 'lay-back' option allows panels to fold back against adjoining walls (available in 2-panel and 2+2 formats)
  • Square cut panel corners for improved aesthetics
  • Bi-fold handle fixes panel at top and bottom
Scope of Use
  • Suitable for broad residential use
  • A good option for maximum unobstructed views and ventilation
  • Need to be used in defined maximum sizes according to the wind exposure
Limitations on Use
  • Recommended maximum 2100mm high doors in Extra High wind zones. For larger sizes consider using the Metro Series and APL Architectural Series
  • Careful consideration of bi-fold use is required when projecting on to decks or pedestrian areas (lay-back option available in this situation)
  • Consider the ease of reaching to the bi-fold handle if the window is placed beyond a bench
  • Open bi-folds need to be monitored if windy conditions occur
  • Free-swinging single panels not recommended
Statement of Building Code Compliance
  • Designed, tested and manufactured to meet NZS 4211: Performance of Windows, and NZS 4233:  Glazing in Buildings, Parts 1-4
  • Designed and tested to conform to NZ Building Code, including Clause E2
In-Service History
  • Extensively used in residential projects throughout New Zealand for more than 40 years with continuous design upgrades
  • Widely used by homeowners, builders, Group home builders and specifiers
Other Performance Attributes
  • Window and door warranty provided under normal conditions of use against failure of materials and workmanship for a period of five years
  • Surface finish is covered by a separate performance warranty dependent on the actual finish selected
  • A hardware/componentry warranty is offered against defects in manufacturing, functionality and surface finish for a period of five years, provided care and maintenance guidelines have been followed
E2 External Moisture compliant
External Moisture
Data Sheet
Span Tables
Declare Label


Altherm Care, Maintenance & Warranty Brochure (with AGP)


Altherm on Masterspec
Full Specification
Specification Clause
Specifier Guide
WGANZ Guide to E2/AS1
Altherm Design Brochure


AGP Cleaning & Maintenance
AGP Condensation Guide
AGP Visual Quality of Glass
APL and Sustainability


Manufacturer Contact List
CAD/PDF Details
Full Set of Drawings


Altherm Residential Bi-Fold Window Two Panel


Altherm Residential Bi-Fold Window Meeting Stiles


Installation Details
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Altherm Residential Bifold Window on Stucco


Altherm Bifold Window

Stylish contemporary lines, effective thermal technology and unwavering attention to detail have made Altherm a favourite with architects, designers and homeowners across New Zealand.

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