Reveals on Precast Panels

Reveal strips can add visual interest to a building clad with architectural precast concrete panels while eliminating some of the aesthetic concerns that develop when planning panel configurations.

Used effectively, reveals offer the simplest way to break up the expanse of an architectural precast concrete panel or to keep the visual appearance from focusing on any differences that may occur in texture or colouration between panels.

Reveals, typically, measure 12 mm to 18 mm deep and 18 mm to 100 mm wide, with 45- to 60-degree bevelled edges allowing for ease of stripping. It’s important to remember that a reveal, regardless of its depth, reduces the structural thickness of the panel. As a result, when a deeper reveal is required than is typical, its location and effect on the panel’s structural performance must be considered.

Reveals and demarcations transform simple shapes into non-routine, visually arresting forms. The reveal can be used to separate multiple finishes, mixes or textures. When exposed aggregate is used, a reveal or demarcation feature is required to keep the retarder from spreading to adjacent areas.

A single step in thickness is sometimes used to separate surfaces and/or finishes. The exterior articulation helps modulate the scale of the building.

Flat, windowless surfaces divided by reveals or demarcation features tend to call less attention to texture and color variations.

When desired, the scale of large panels may be reduced by using reveals. The reveal should be wider than it is deep so the panel can be stripped without damaging the mould. Generally, the minimum positive draft for ease of stripping a panel from a mould is 25 mm in 100 mm with one in eight (1:8) preferred.

Reveals can be single double, layered or repeated. They also can run in patterns or feature various shapes Deep-set reveals are incorporated in facades to give visual relief and may require thickened sections. However, deep-set reveals requiring thickened sections may add some mould costs, along with significant back-forming costs.

Using Reveals To Design Architectural Precast Panels

When you search the internet for the meaning of “reveal,” the first citation in Webster’s electronic dictionary defines it as a verb that means “to open up to view, to display, to divulge or to make known what has been or should be concealed.” It takes additional searching to find “reveal” as a noun in today’s Webster dictionary.

But if you go to the 1913 version of the Webster’s unabridged dictionary, the first citation defines “reveal” as a noun, meaning, “the side of an opening for a window, doorway, or the like, between the door frame or window frame and the outer surface of the wall; or, where the opening is not filled with a door, etc, the whole thickness of the wall; the jamb.”

Ironically, the use of reveals in precast design in the 21st century has much more to do with its use as a verb than it does with 1913’s foremost definition of “reveal” as a noun, despite its architectural context in that form.

As we all learned in primary school, a verb is an action word. That’s exactly what architectural reveals provide to a precast panel: the visual action. Reveals do much more than simply articulate the thickness of the precast.

Designing reveals with architectural precast components creates the most fundamental detail for producing a beautiful precast project. Precast by its very nature is made up of panels or component pieces that are assembled to create the building’s structure or skin. Those pieces obviously have joints between them, and reveals’ most pragmatic uses come in articulating those fundamental joints. These joints can be either emphasized or minimized and hidden by the creative addition of reveals.

Other pragmatic uses for reveals come in providing drips and/or small horizontal shelves to protect openings and control moisture as it moves along the exterior surface of the precast.

Design

Reveals typically are designed where there are changes in the precast surface. For example, a shift in the panel’s finish from smooth to textured can be emphasized by using a reveal at the point where the surface texture changes. Reveals also work well where fundamental materials change within a precast panel, such as from an exposed-aggregate finish to a non exposed-aggregate finish within the panel.

Reveals allow a crisp, clean transition between these different textures or finishes.

Lastly, reveals can be placed where there are directional changes in the precast surface, such as between a vertical surface and a cornice or bullnose detail. These elements within a wall design can be emphasized or de-emphasized through the use of reveals.

However, reveals can be much more than a joint or line of demarcation between textures or finishes. Designing reveals in varying shapes, sizes and depths for a precast wall can transform what initially might be considered a mundane, solid surface into a rich texture of shade and shadow, bringing visual interest to the building’s façade.