Metal Roof Innovations Central

What is a Trapezoidal Rib Roof Profile?

Posted by Kimberly Reichert on Apr 29, 2019 12:03:47 PM

A trapezoidal roof profile has a ribbed trapezoidal-shape pattern across the panel. This means, it is a quadrilateral (or a four-sided shape – see Figure 1) that has just a single pair of parallel sides. Sometimes, trapezoidal roofs are mistakenly referred to as corrugated. This is a misnomer as the corrugated profile has a repeating wavy pattern across its surface.Trapezoidal rib roofs are popular with producers because the shape makes them very material-efficient (a high strength-to weight ratio). 

S-5!® Word of the Week - What is a trapezoidal rib roof profile-2This makes for a very cost-effective profile. The shadows of the trapezoidal shapes offer clean lines whether installed vertically, diagonally, or horizontally. They also possess good structural characteristics and can carry design loads well (e.g. for snow and wind uplift). However, it is not considered as premium a profile as standing seam due to its attachment method.

Typically, trapezoidal roofs are face-fastened, or through-fastened (aka, exposed fastened) – meaning the panels are held in place by fasteners that pierce through the material with washered screws anchored into the structure. Rib spacing varies from 6” to 12”, and may have tiny “minor ribs” between that help to stiffen the panel. Although they may generally look the same at a glance, the exact dimensions and angles vary from one producer to the next. Popular all over the world, trapezoidal rib roofs are less expensive than conventional standing seam roof profiles. And there are actually standing seam profiles that also borrow the benefits of the trapezoidal shape. In fact, they are industry standards for large buildings owing to cost-efficiencies of the trapezoidal rib geometry.


S-5!® Trapzoid Shape with 2 Parallel Lines

Figure 1


It Worked for the Egyptians…

S-5!® Trapezoid Shape on Ancient Pyramids 

There is an excellent analogy to use to explain the good structural characteristics of the trapezoidal rib roof profile. Consider the ancient pyramids. A pyramid shape is but a trapezoid with the top cut off. Pyramids have literally stood the test of time – over thousands of years. The solid design of the pyramids proves that the shape assists with load distribution creating a more stable supporting structure.

S-5!® Word of the Week - What is a trapezoidal rib roof profile-2


Word De-Construction

Word of the Week: Trapezoidal


PRONUNCIATION: \ ˈtra-pə-ˌzȯid-al


SENTENCE: // The trapezoidal roof design paired with the RibBracket™ I-IV ensures adequate space for wire management during solar PV array installation. 

SYNONYMS AND RELATED WORDS: R-panel, trapezoidal rib 


THE RIBBRACKET™ I-IV: S-5! offers a prime solar solution for the vast majority of trapezoidal roof shapes. The RibBracket comes in four width offerings – allowing adjustment for a variety of trapezoidal widths. (The “legs” also flex to accommodate different dimensions and angles). Visit the S-5! website to learn more about the specific seam profiles each bracket fits.

Below you will find dimensional drawings of the S-5! RibBracket. The higher profile design of our bracket also ensures ample spacing between roof and solar modules. Its four attachment points serve to increase its holding strength. Whereas other products attach straight into the top of the trapezoidal profile, RibBracket attaches into the sidewalls developing far greater holding capacity for direct-attach applications. And the top slot provides for “tweaking” the alignment of modules during installation.

S-5!® RibBracket I

S-5! RibBracket I

S-5!® RibBracket II

S-5! RibBracket II

S-5!® RibBracket III

S-5! RibBracket III

S-5!® RibBracket IV

S-5! RibBracket IV


JUST FOR DIRECT ATTACH SOLAR: The S-5! RibBracket is designed to fit the most common exposed-fastened, trapezoidal roof profiles in North America. No need for messy sealants. The bracket has a double seal with EPDM rubber gasket already within the bracket base and protected from UV exposure. Special EPDM washered screws furnished with the RibBracket complete the double-seal assembly.

Learn More about the RibBracket™

S-5!® - Trapezoidal Roof Profile with RibBracket™ and PVKIT™ 2.0

Trapezoidal Roof Profile with RibBracket™ and PVKIT®

SolarFoot™ and ProteaBracket™ 

S-5! also offers two other products that are prime attachment solutions for solar PV mounting: SolarFoot™ and ProteaBracket™. Use the SolarFoot for rail mounting solar panels. It is compatible with any “L-Foot”. Want a product that does it all? The fully adjustable S-5! ProteaBracket can be utilized for either direct-attach with the PVKIT or for side and bottom rail mounting. No L-Foot ever required—a fully versatile one is included with ProteaBracket. And all S-5! products are fully load tested for engineered applications. Just consult our website or ask one of our friendly technicians!

S-5!® SolarFoot™ Bracket

S-5! SolarFoot™

S-5!® - ProteaBracket™

S-5! ProteaBracket™

WHAT ABOUT STANDING SEAM TRAPEZOIDAL ROOF PROFILES? Consider the S-5-V clamp. This clamp is designed to fit double-folded or trapezoidal snap lock (vertical) standing seams. The S-5-U and S-5-V Mini are two other versatile clamps we offer for this style of roof profile. This clamp fits vertically-oriented seams as well as horizontally-oriented seams. In addition, the S-5-H, H-90, and the S-5-U as well as their corresponding mini versions all fit variations of the trapezoidal rib profile. 

Here are two examples of standing seam varieties: Trapezoidal Double-Fold and Trapezoidal Snap Seam profiles (Figure 2 and 3, respectively).

S-5!® Trap Snap Seam

Figure 2

S-5!® Trap Double Fold

Figure 3


Why S-5! Clamps are The Right Way™ to Mount Almost Anything to a Trapezoidal Roof:


S-5! Trapezoidal Rib Profile Compatible


RibBracket™ I-IV

S-5-U Clamps

S-5-V Clamps

S-5-H Clamps

S-5-H-90 Clamps



S-5! PVKIT® Solar Solutions

Learn More Button - S-5!®

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Tags: metal roof brackets, standing seam metal roof

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Why do industry experts endorse S-5!? Because they know our rigorously researched, tested and quality engineered products deliver unprecedented value and innovative excellence. And all of our USA-made clamps and brackets are backed by an industry-leading limited lifetime manufacturer warranty.