Metal Building Options – Canopy & Purlin Extensions
Many metal building customers do not realize that, by default, metal buildings do not have "eaves" or "soffits" similar to what they are used to seeing on more traditional forms of construction.
In the metal building industry, the formal name for roof extensions on the front and back sidewalls are "canopy extensions" and the formal name for roof extensions on the left and right endwalls are "purlin extensions. If the terns "sidewalls" and "endwalls" are foreign to you, then you might want to read our blog article entitled Steel Buildings - Learn The Basics.
Standard Metal Buildings
One of the areas of concern we often hear from customers, especially those who are considering a metal building for residential or retail use, is that they don't want the building to look too industrial or commercial or simply look like a metal box.
We always discuss the option of canopy and purlin extensions with customers who are looking to soften the appearance of their metal buildings. By default, the roof of metal buildings does not extend past the wall line by much more than 3-4 inches. The tan building pictured above is a simple metal building without any canopy or purlin extensions and, as a result, it does have an commercial appearance. The rustic red building pictured has 2' canopy and purlin extensions and, as a result, the look is rather softened and more closely resembles traditional stick construction.
Canopy & Purlin Extensions Enhance Metal Building Appearance
Canopy and Purlin extensions are simply unsupported extensions of the roof beyond the wall of the building and are defined by the distance they project past the metal building wall. This distance, or measurement, is often referred to as "projection". The maximum amount of projection for a canopy or purlin extension depends on the wind load the building is being engineered for, but is generally 5'.
Additionally, while you can have canopy or purlin extensions without soffit material, this is the exception to the rule. Most of the canopy and purlin extensions we provide include soffit material of PBR or PBU panel. If you are not sure of what these panels look like, you can find detailed information about them on the Panel Types page on this website. With only the rarest of exception, canopy and purlin extension trim and soffit material are polar white.
Do canopy and purlin extensions serve a purpose other than simple aesthetics? Yes. Canopy and Purlin extensions with a large projection, for example 5', on metal buildings with low eave heights can provide cover from the elements for those entering the building through walk doors and rollup doors. Of course, the same canopy and purlin extensions on a building with a 16' or 20' eave height would likely serve no functional purpose.