Sliding and casement windows (C) DanieL FriedmanGuide to Defects in Slider or Glider Windows

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Guide to slider or glider windows & window inspections for defects & leaks: this article describes common defects (air or water leaks, out of square, operating difficulties) found in slider windows used in residential buildings

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Sliding Windows or Gliding Windows - Inspection Guide

Sliding and casement windows (C) DanieL Friedman

Slider windows such as the page top installation on a cabin in Northern Minnesota and at left at a New York home can offer large horizontal expanses of glass and operable sash that do not interfere with interior or exterior space.

Our photo shows Andeson gliding windows (photo-right) that we [DJF] recently had installed during a log cabin renovation in Two Harbors, MN.

As discussed in Best Practices Guide to Residential Construction Chapter 3, BEST PRACTICES GUIDE: WINDOWS & DOORS, designing a window that slides sideways presents some challenges that we list here:

  • The lower track must rely on weep holes to drain away water, and second, any grit that collects in the lower track tends to impair the sliding action.
  • If the weeps clog up, water may find its way into the sill or framing over time. Also, pushing a stuck window sideways is an awkward motion that tends to strain the back. (Also see STORM WINDOW WEEP HOLES).
  • As with double-hung windows, ventilation is limited to rougly 50% of the framed opening, and slide-by weather-seals are less effective than compression seals. And if the slider is large enough it can also qualify as an egress window.

List of Glider / Slider Window Defects

To avoid problems with slider windows, look for high-quality windows that slide freely. Also, consider alternatives such as a picture window with a casement along one side for ventilation. On some glider windows, especially high-volume lower-quality units we [DJF] have observed these defects: Glider window details (C) Daniel Friedman
  • Lost window glass seal and condensation in insulated glass gliding windows [see photo below right]
  • Improper installation of the glider window into a rough opening and ultimately finish opening that is out of square. The result can be poor window sealing, difficulty latching the window shut, and air or water leaks.
  • Air leaks around the window frame
  • Water leaks into the building wall and rot or insect damage traced to a gliding window frame that does not drain properly, possibly debris-clogged drain openings
  • Sloppy flashing or caulking around the window leading to leaks into the building walls
  • Vicinity caulking at windows - is not a problem unique to gliding windows, our photo (above left ) shows what we call "vicinity caulking" - the installer placed caulk "in the vicinity of" the joint between the window and the building exterior siding.

Rusted out steel glider slider window (C) Daniel Friedman

Openings in sealant around windows allow water to leak into the wall. A casual inspection may see caulk and not recognize that the caulk or sealant was not applied effectively.

Most modern windows include an installing flange that deters leaks into the wall cavity at these defects, but sending wind-blown rain behind the wood siding on the home in our photo above risks siding damage and rot or insect attack on the structure.

  • Rust-out of the frame or track on steel-framed glider windows. We suspect that clogged sliding window track drain openings contributes to this problem, shown in our photo [above-left].

Examples of Antique & Site-Built Slider/Glider Windows

Below we illustrate a wood framed sash multi-light sliding window installed in a stone masonry building in Buenos Aires (below left), circa 1935, and a site-built wood frame slider installed in the same Minnesota green cabin shown at page top, but before renovations (below right).

Rusted out steel glider slider window (C) Daniel Friedman Rusted out steel glider slider window (C) Daniel Friedman

Frequently Asked Questions (FAQs) about Sliding or Gliding Windows

Question:books on details of antique metal sliding windows?

Are there any book or article in the website that shows details or sections of an old metal sliding window? (or gliding window, I don't know the correct name) thanks! - M.O.

Metal slider window drain opening clog (C) D Friedman Metal gliding window (C) Daniel Friedman


Lost seal on metal frame glider slider window (C) D FriedmanWe call them sliding windows but window manufacturers such as Anderson Windows & Doors calls them gliding windows. Our photos at left illustrate a 19780's metal frame slider window that was one of most on a condominium complex, all of which had lost their seal, leading to fogging between the panes of the double-glazed unit.

Our slider windows above show a clogged drain opening in the lower track of a 1980's vintage metal-frame sliding window (above left) and an aluminum framed gliding window in an apartment in New York (above right).

If you can describe a specific question or concern we'll be glad to do more research - no fees are involved.

Here is a link to Anderson's information on window gliders:

Skylight & Window Manufacturers & Product Sources

  • Andersen Windows and Doors Skylights and roof windows with exterior sash clad with glass-fiber-reinforced material
  • Milgard Windows and Doors Skylights with aluminum frames (thermal break optional) with vinyl subframes on operable models; optional motorized controls with rain sensor
  • Pella Windows and Doors Wood interior, aluminum exterior, optional motorized controls, and manual or motorized fabric-pleated shades
  • Roto Frank of America Wood interior, aluminum exterior, optional motorized controls, and manual or motorized fabric-pleated shades; Sweet16 model fits 16 in. o.c. framing
  • Velux America Inc. Skylights and roof windows with wood interior and aluminum-clad exterior. Options include insect screens, blinds, motorized controls and shades with rain sensor, electrochromatic glass, and flashing kits for metal and tile roofs and mulled units
  • Skylight Light Tube Manufacturers & Sources
  • SolaTube Light tubes from 10 to 21 in. in diameter; options include electrical lighting, daylight dimmer, and integral bath fan
  • Sun-Tek Skylights Light tubes from 10 to 21 in. in diameter; options include electrical lighting and multitube Spyder skylight
  • Velux America Inc. Sun Tunnel light tubes from 14 to 22 in. in diameter with flexible or rigid tubes

Industry Associations for Windows & Doors

  • American Architectural Manufacturers Association (AAMA)
  • Efficient Windows Collaborative
  • National Fenestration Rating Council (NFRC) Sustainable by Design
  • Shareware calculators for sun angles, solar heat gain, and shading
  • Window and Door Manufacturers Association (WDMA)

-- Adapted and paraphrased, edited, and supplemented, with permission from Best Practices Guide to Residential Construction.

See our Window Types, Guide article series where we describe the selection and installation of windows and doors, following best construction and design practices for building lighting and ventilation, with attention to the impact on building heating and cooling costs, indoor air quality, and comfort of occupants. We review the proper installation details for windows and doors, and we compare the durability of different window and door materials and types.


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