Substructure Archives

Oil canning is a broad term in the world of metal panel products and is considered one of the most vexing issues facing metal panel installations. The Metal Construction Association (MCA) defines oil canning as a “visible waviness in the flat areas of metal roof and metal wall panels.” Oil canning, also known as elastic buckling or stress wrinkling, occurs in all types of metal panels. While it is a common concern, there are steps you can take to minimize the problem.

Here, we’ll focus specifically on oil canning/distortion with metal flush wall systems, which for MBCI products includes our FW Panels and Designer Series. The type of oil canning that occurs with flush wall systems is not caused by anything dealing with the product itself or with how it’s manufactured. Rather, it is a consequence of what installers are putting the metal panels on and how the installation is done.

Installers must correct any out-of-plane areas of the substructure to prevent metal panels from oil canning.

The simplest way to explain the phenomenon is that if the substructure is out of plane, i.e., not in alignment, stresses are put onto the panels that will create an appearance of oil canning. After all, as the old adage goes, you only get out what you put in. In the case of flush metal wall systems, the panels will look no better than what they are put on top of. If the substructure is wavy, out of plane, up or down, in or out, that condition will affect the panels’ performance and appearance.

Certain tolerances will have an effect on the panels’ appearance. With MBCI’s FW and Designer panels, tolerances would be 1/4 inch and 20 feet outward (away from two attachment points) and 0 inch and 20 feet inward. This means that if panels are forced into an inverted convex position, they will show stress rippling or oil canning more severely than when they’re stretched over a concave position, i.e., there can be some tolerance outward but zero inward.

With these types of panels, the biggest concerns with oil canning/distortion are aesthetics, but performance problems are also of concern, including possible engagement or sealing of the side joints.

Minimizing Oil Canning/Distortion of Panels

Prior to installation, installers should be checking the substructure with string lines or lasers and correcting or shimming any areas that are out of plane, especially since oftentimes substructures, such as stud walls or structural walls that the metal panels are attached to, are installed by other trades. Metal panel installers need to scrutinize each aspect for alignment and then either correct or shim to bring it within tolerance and within plane.

As is true with any metal panel product, for best results, proper handling and installation go a long way towards preventing the problem of oil canning in the field.

To find out more on how to minimize oil canning on your MBCI metal wall panels, contact your local MBCI representative, and sign up for our newsletter to subscribe to our blog.

Installers take note! It is your responsibility to ensure the substrate material over which you place the metal panels is in proper alignment before beginning installation. Otherwise, you can suffer some significant negative impacts on the overall appearance of the system.

As we’ve discussed in a previous blog article, Choosing Proper Substrates for Metal Roofing Systems, the substrate (or substructure) rests underneath the metal panels is a key part of the roofing or wall system. It serves two main functions: to act as a base to which the metal material is attached and to serve as a structural member to transfer loads to the primary framing system.

Knowledge is Power

Too many times, inexperienced metal building sheeting installers or sheeting-only contractors may not realize how big an impact alignment can have; it’s very easy to get too far into the process before recognizing there’s a problem. The issues must be dealt with at the very beginning of the process as well as the way through the installation of the panel system, whether it’s roof or wall panel installation, and must be checked frequently.

Major Misconception

One common misconception, especially for those new to the panel system, is that aesthetic anomalies are a result of panel quality. When troubleshooting, the manufacturer will ask a series of questions about the installation and alignment. However, by that stage, the installer may be beyond the point where it’s an easy fix, depending on the circumstances.

Key Considerations

Understand the general panel installation characteristics by reading the installation manual. Become familiar with which screws and clips to use, and how the panels physically connect as well as types of insulation systems that work well with the panel system and if there are any limitations related to insulation types or thicknesses.
Installers must be certain that the substrate material they’re installing over, whether metal or wood or something else, has been properly erected and properly aligned before panel installation begins.
As they’re putting the panels over the substrate, installers should be checking the alignment, whether vertically/horizontally along the leading edge of the panel or inward and outward on the panel itself. With most metal panels, major variances in the substructure will cause the panel to accentuate any errors. As a result, the panels will look unattractive and be difficult to install.
When the panel installation first begins, the installer might not immediately recognize there’s a problem. A variance in the steel or in the substructure can have a big impact, which won’t be known until it’s too late. As an example, consider erecting half a wall on a cloudy day without checking alignment. At the end of the day, it looks fine, but the next day when the sun is shining on it, the “aesthetic delights” due to misalignment are obvious.
Check panels during installation for any damage due to handling, surface irregularities and how it engages or lays on the steel. Do not install any “suspect” panels and contact the manufacturer as needed.

Types of Problems with Alignment

Different types of panels can react differently to a substructure out of alignment. Some are more forgiving, and some are terribly unforgiving.
Overdriving fasteners combined with improper alignment is a killer 1-2 punch.
If alignment is not properly addressed/corrected prior, installers often try to push and pull the panel out of plane, resulting in “oil canning,” a common rippling effect that occurs with improper installation. It should be noted, this often is a direct result of the substrate and/or improper installation and does not have any bearing on performance, weather-tightness and warranty. It doesn’t look nice but is not a cause for rejection.
If the steel is out of alignment, the panels can be difficult to engage and perform the way they should.

What Can You Do?

Using a level, laser or a string line, an installer can measure/check the amount that the substructure is either going in or out of plane and correct as needed. For instance, the plane is zero mark-perfectly plumb, perfectly level. There’s an allowable tolerance that the substructure can be out of plane and still be acceptable. Manufacturers often publish recommended tolerances that should always be reviewed. The preferred tolerance being convex (outward) and never concave (inward).

Other Considerations

The main takeaway here is that steps should be taken to prepare a substructure to properly receive the metal panels. Then, diligently check as panels are being installed to ensure proper alignment is maintained and the installer is not inadvertently pushing and pulling them out of alignment, which could result in less than favorable final appearance.

Tag: Substructure

Oil Canning and Flush Metal Wall Panels