Glass Floors: Designing a Walkable Skylight

By Tim Casey

When remodelling a home or renovating a business, it’s worth considering including a custom walkable skylight. This type of skylight differs from a traditional one in that the space, whether a roof, deck or elevated walkway, is completely usable. The glass is load bearing and designed to be walked on, so no square footage is lost. Therefore, it’s best to think of this skylight option as more like a waterproof glass flooring that adds internal and external architectural interest; imparts a more open, airy aesthetic; helps reduce energy consumption by minimizing dependence on artificial lighting; and imbues a space with mood-uplifting natural light.

Aesthetics and Function
When designing a walkable skylight, one of the first considerations is the type of glass to use: coloured, clear or frosted. Each will impart a different look and feel, as well as impact function. For instance, if wanting to capitalize fully on the benefits of daylighting, then clear glass would be the best choice.

Safety First
Next, and more importantly, is safety. Every walkable skylight should be manufactured using anti-slip glass. This type of glass is treated or processed to generate more friction when walked on so it does not pose a slip or tripping hazard. Anti-slip options include permanently fusing little pieces of glass aggregate to the walkable glass surface in a kiln; baking an anti-slip product onto the glass surface, which is akin to silk-screening; and using the technique of acid sketching where portions of the glass surface are removed, resulting in varying depths of glass.

A walkable skylight differs from a traditional one in that the space, whether a roof, deck or elevated walkway, is completely usable and, therefore, is more like a glass floor. Photo courtesy Jockimo Inc.

When properly designed and manufactured, glass failure is unlikely but it’s not impossible. Because of this, the glass should be three-ply (three pieces of glass ‘sandwiched’ together). This way, if one piece breaks, the other two will still safely hold the structural load and no one will fall through the floor.

Exact glass thickness will depend on the project’s specifications. It has a lot to do with the deflection rating — the amount a piece of glass bends or flexes at its centre point when a force is applied — and the support system around the glass, among other technical factors. Generally speaking, though, glass used in a walkable skylight should be 1.25 inches thick.

Placement and Size
Another critical aspect of the design phase is where to place the walkable skylight. If looking to maximize daylighting benefits, then attention must be given to potential glare and additional heat.

In terms of size, the ‘sky’s (almost) the limit’ given the floor is walkable. Keep in mind any project must comply with local and national building codes, safety measures and best practices. This will put some limitations on size, shape and specifics.

Tim Casey is the founder and owner of Jockimo Inc., which specializes in decorative architectural glass products for designers and architects. Tim grew up in the glass industry, and he continually develops new and exciting glass products and technologies that expand what is possible with architectural glass.

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