Thresholds and Components

Sills or thresholds need to be coordinated and should support both the door system and number of door panels. Thresholds should also be selected based on weather exposure and floor transition.

Thresholds are available in at least three different profiles and should be specified according to the project design needs. Fully recessed thresholds are an ideal application to create seamless blending between spaces. Flush sills are designed to be recessed into the floor, creating a level transition between the finished interior floor surface and the exterior. Flush sills can incorporate the same finish flooring between the sill tracks. Flush sills offer seamless transitions and are a preferred solution for covered openings. While recessed thresholds used to suffer from poor weather performance, new sills allow for full recession at or below the finish level. For areas with open weather exposure, weather resistant weeping tracks allow for the recessed sub sill to capture and drain water away from the building via tubes. Three different leg heights allow for performance in moderate to extreme weather conditions.

Raised sills are intended to have a raised profile and sit up above the exterior. Depending on the manufacturer, raised sills come in varying interior leg heights. Raised sills offer a greater degree of weather resistance. Raised sills, or special weather-resistant sills, are the preferred solution for weather-exposed openings. Ramped sills are commercially compatible and offer ADA compliance when there is more than a ½-inch change in the sill height compared to the walking surface. All threshold styles are typically thermally broken.

The grade of material for the threshold should be specified, as well as the bearings, hinges, and wheels of the door panels. Nylon plastic and stainless steel are the most commonly seen materials. Stainless steel components usually offer the best durability and longevity for large or heavy door panels.

To control air leakage and improve energy efficiency, Multi Panel Door systems also rely on a mix of perimeter seals applied to each door panel. Top seals can be brush type to allow for the smooth operation of the door while still restricting the transfer of air and weather. The bottom or sill seal may be composed of low-friction coated rubber applied to the bottom of the door, creating a full seal yet allowing for the smooth operation of the door panels. Continuous seals along the edges of each door panel may be compression rubber gaskets, fin brush seals, or both. Careful application of high-grade seals provides a tight seal when the doors are closed and helps to maintain pressure and weather resistance.

Superior manufacturers will offer AAMA certification and cycle testing, demonstrating the sustainability of their hardware and components over time. This allows for greater confidence in design decisions.

Screens

Larger door openings also require larger screens, where desired, designed specifically to complement large openings. For multiple-panel systems, a fully retractable screen that is only seen when in use can be seamlessly integrated into the system. Door systems may incorporate single screens or double screens (coming from opposite sides) depending on the width of the opening. Double screens at angles accommodate applications such as zero post corners.

Integrated pleated and non-pleated screening solutions help protect the interior from insects or debris, and act as an added filter, when necessary, between occupants and the outdoors. A pleated mesh screen system offers the best protection against insects, leaves, and twigs blowing in. The pleated construction makes the screen material more stable, as it resists sagging, and keeps it compact, helping it collapse neatly to one side when not in use. It is also the most cost-effective solution. Non-pleated screens provide excellent levels of transparency, allowing for uncompromised views.

Movable glass panel door systems with a blind option deliver complete privacy and, in warm climates with direct solar exposure, improved energy efficiency by deflecting harmful UV rays and reducing heat transfer.

In partnership with their focal aesthetic role, advancements in movable glass panel door systems and component technology allow any design to achieve energy efficiency goals, performance, and service life, creating a project that transcends trends.

SOURCES

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Amanda Voss, MPP is an author, editor, and policy analyst. Writing for multiple publications, she has also served as the managing editor for Energy Design Update.