In architectural residential builds across New Zealand, the joinery system is one of the most visible and technically significant specifications the architect makes. Thermally broken aluminium from fabricators like Altus and Alspec is the most common system in Auckland residential work, meeting NZBC H1 energy requirements while offering a wide range of profile depths, colours, and opening configurations. Timber, steel, and composite systems are specified where the design calls for qualities that aluminium alone cannot deliver. The system selection happens at concept design stage and has significant cost and programme implications.

What is thermally broken aluminium and why is it standard?

Thermally broken aluminium joinery incorporates a polyamide thermal break between the inner and outer aluminium extrusions. This interrupts the thermal path through the frame, which would otherwise conduct heat efficiently between the warm interior and the cold exterior. Without the thermal break, aluminium frames can develop condensation on their inner face in Auckland's cooler months, which leads to water damage to lining and sill materials over time.

Altus and Alspec are two of the main aluminium joinery fabricators operating in the New Zealand market. Both offer thermally broken systems with comparable performance in the residential range. Their extrusion profiles differ in visual weight and depth, and architects often specify one over the other based on the profile aesthetic or specific hardware compatibility requirements. Both systems have local fabricators who produce windows and doors to the architect's schedule, with lead times of 10 to 14 weeks for standard production.

W O Flatz Construction works with both Altus and Alspec systems on Auckland architectural projects. The procurement process starts from the joinery schedule, which the architect produces as part of the construction documents. Every opening is listed with its system, profile, glazing specification, colour, hardware, and sill detail.

When do architects specify timber joinery?

Timber joinery is specified when the design requires visual warmth, profile depth, or a connection to the character of the existing building that aluminium cannot provide. On Auckland villa renovations, new joinery that needs to read as consistent with the existing character-home fabric is often specified in pine or hardwood to match the original window proportions and detail. Timber also allows custom profiles that are not available in standard aluminium extrusion.

Timber joinery costs more than aluminium in most configurations and requires more maintenance over the building's life. Paint or stain systems on timber joinery in exposed Auckland weather conditions need recoating every five to seven years on south-facing facades, more frequently on north-facing facades subject to UV and rain. The maintenance obligation is significant and should be discussed with the homeowner at specification stage.

Well-designed and maintained timber joinery on an Auckland villa adds to the heritage value of the property and is consistent with the original construction. W O Flatz Construction has extensive experience installing timber joinery on villa projects and understands the installation details that affect long-term weathertightness and performance.

What about steel joinery?

Steel joinery is specified when the design requires an extremely slender frame profile that aluminium and timber cannot achieve. Steel's tensile strength allows thinner sight lines around glazing panels, which creates a more open visual connection between inside and outside. Steel-framed glazing systems produce visible frame widths of 20 to 30mm, compared to 60 to 80mm for equivalent aluminium. The aesthetic is distinct and is used on specific architectural projects where the visual quality of the frame-to-glass ratio is central to the design intent.

Steel joinery is significantly more expensive than aluminium, requires thermal break detailing at connections to manage condensation, and has longer lead times from specialist fabricators. It is not a standard specification, but on the right project it delivers a visual result that no other system matches. Auckland architects who specify steel joinery work with specific fabricators who have the capability to produce and install it to the required standard.

Bifold versus sliding versus tilt-and-turn: which suits what?

Bifold doors are used where the design calls for a large uninterrupted opening between internal and external spaces. They fold back to a stack at one or both ends and leave the opening clear. The limitation of bifold systems is that the folded panels occupy floor space at the end of the travel, and the panel-to-panel hinges are visible in the open position. Standard bifold spans run up to seven or eight metres with conventional aluminium systems.

Sliding doors use less floor space when open and offer cleaner sight lines than bifolds in the open position. Large-format sliding doors with a single or double panel can achieve clear spans up to six metres. The limitation is that even a large sliding door only opens approximately half the total opening width, as one panel always covers part of the frame.

Tilt-and-turn windows offer ventilation flexibility: tilting inward at the top for restricted ventilation, or turning fully inward for cleaning and maximum airflow. They are common in European architecture and are specified on Auckland projects where the design has a European influence or where inward-opening windows are preferred for specific weathertightness or acoustic reasons. Tilt-and-turn systems require clear interior space for the panel to open inward.

To discuss joinery specification for your Auckland architectural project, contact Hunter or Wallace Flatz at W O Flatz Construction.