Clamps and Brackets FAQs

How much load will S-5!® clamps hold?

The answer to this question varies with the load direction, the seam profile, the roof material and the clamp model. We have done hundreds of tensile load tests parallel to the panel seam and on various gauges and profiles, we have tabulated the results for your convenience. See Load Test Results for that information. In this load direction any loads that are introduced into the clamp will accumulate into the point of fixity. Panels must be adequately attached to resist these loads.


With very few exceptions, the attachment of a single S-5! clamp (even the “Mini”) to the seam will be stronger than a single point of attachment of the seam to the building structure. Hence the “weak link” is not the S-5 clamp, but the attachment clips that hold the metal panels to the building structure, or the beam strength of the roof panel seam, itself. Ultimate loads normal to the panel seam (both positive and negative) are more a function of the panel’s beam strength, and the failure strength of the panel’s attachment clips than of the holding strength of the S-5! clamp on the panel seam. These values will also change with various attachment spacing.

ASTM standard E-1514-93 for structural standing seam metal roofing states that panels must withstand a minimum 200-pound point load in positive (downward) pressure at the panel’s weakest point (the flat of the panel). The Army Corps of Engineers Technical Instructions for metal roof design spec (TI 809-29) says that the same value should be 300 pounds.

Almost any structural metal panel system will meet the above specifications easily. Of course the seam area is also much stronger than the panel flat. Hence, as a general rule, 300-pound positive point loads on the panel seam (above an S-5! clamp) should do the panel no harm. HVAC units have been mounted in this fashion on numerous projects, utilizing four, six or eight clamps for a single unit of considerable weight, and dividing the weight of the unit evenly over those point loads. Of course, the building structure must also be designed for these loads.


S-5! clamps have been laboratory tested on various seam types, profiles and materials for ultimate failure loads parallel to panel seam (“drag” type loads). The ultimate load-to-failure results vary with individual panel profiles and gauges. When used on some “applied cap” architectural type seam styles, for example, S-5! may yield low load-to-failure results and may therefore be unsuitable.

Also, keep in mind that the setscrews, which make a small dimple in the panel seam, optimizing holding strength, are normally tensioned to 115 inch-pounds for test purposes. This is because the tools normal to the trade are rated at this tightening torque. But there are some exceptions to this rule. On some profiles and gauges in steel, screw tension of 115 inch-pounds will not adequately dimple the panel seam. In such cases, load-to-failure values would be rather low, but for increasing the screw tension. For this reason, the tests are run with higher screw tensions on some profiles. On the other hand, there are very few seams on which the clamp screw engages only two thicknesses of sheet metal. When such material is thin-gauge aluminum or titanium-zinc, the setscrew may pierce through at normal tensions of 115 inch-pounds. For that reason, such seams are tested at lower set screw tensions. Regardless of application, appropriate factors of safety should be always employed and screw tension verified when relying on these test results.

What profiles will S-5!® clamps not fit?

S-5! clamps will not fit on face-fastened trapezoidal rib or corrugated type panels.

S-5! has a line of brackets for face-fastened roofs. They will also not fit on most “batten” seam type panels, except for the traditional batten seams folded joints.

On what profiles should S-5!® clamps be used with caution?

There are some seams on which S-5! clamps should either not be used or used only with caution. Among them are snap-on cap type architectural seams and seams of very light or very heavy gauge material as well as some nail-strip or nail-flange profiles.

What if the panel seam I'm using has not been tested?

Many panels are identical, or almost identical, to those tested. Our Clamp to Seam Matching Tool searches through all of our known test data, providing the most up-to-date and definitive answers on where to begin your roof transformation. If your profile can still not be identified here, we will be happy to test it for you—in most cases, free of charge. Contact at our office for further details.

How can I be sure that S-5!® setscrews won't damage my panel?

We were also concerned about this. We didn’t want to promote a product that solves one problem on a metal roof, while creating another. Our first S-5! prototypes utilized setscrews with a common “cup point”. But, we noticed that such screws gouge the finish of the panel. With the metallic coating breached, premature corrosion is imminent, and any warranty is violated and therefore nullified. So, we went to great lengths to have special stainless steel setscrews custom made to our exact specifications. The point of the screw is rounded to a specific radius and polished to eliminate abrasion to the panel finish when tensioned. We also the use of these special type screws. More info

Should I be concerned about metallurgical compatibility?

Always be concerned about metallurgical compatibility. Incompatibility can cause rapid galvanic corrosion and void material warranties. S-5! aluminum clamps are completely compatible with painted or unpainted G-90 galvanized steel, bare or painted Aluminized , Galvalume, Zincalume, ZincalumePlus, Acrylume Galvalume Plus, Galfan and Galvanneal steel. Of course, they are also compatible with aluminum (painted, bare or anodized). They are also compatible with titanium-zinc (VM & Rheinzink). They are also compatible with stainless steel. The brass clamp is compatible with everything the aluminum clamp isn’t.

Which clamp works best on horizontal seams?

For horizontal seams under .5″
Use the S-5-E and crimp the seam to 180 degrees at desired clamp location.

For horizontal seams under .5″ you may also use the S-5-T or the S-5-S to avoid crimping the seam.

For horizontal seams greater than .5″ and less than .625″ use the S-5-T.

This illustration demonstrates crimping technique, NOT actual location of clamp.

For horizontal seams greater than .65″
For horizontal seams greater than .65″ use the S-5-U in its horizontal orientation or use the S-5-H90.

For horizontal seams greater than .65″ but less than .80″ use the S-5-H.

For horizontal seams less than .65″ you may also crimp the seam as shown above for the S-5-E.

Which clamp works best on nail flange, snap-together profiles?

Nail flange standing seam profiles with relatively low seam heights have become popular in residential and light commercial markets in recent years. They are typically manufactured from 26 and 24 gauge painted steel, but may be fabricated from other materials, as well.

The S-5-N and S-5-N Mini clamps have been designed for application on the popular 1″ nail strip metal roof profiles: Taylor Metals’ Easy Lock™, ASC Building Products’ Skyline Roofing®, McElroy Metals’ Meridian, and New Tech Machinery’s FF100, and roofing types with similar profiles.

The clamp boasts a wider throat that accommodates most nail strip profiles, minimizing the need to field crimp. An angled wall with a nose permits the S-5-N to engage the triangle type profiles during the installation process—there is no longer a need to hold the clamp in place while setscrews are tensioned.

What is the S-5-A Clamp?

The “A” is for “architectural”. This clamp is only used in conjunction with SnoRail™ and SnoFence™. It is not recommended for other utility attachments. Please see the Snow Retention Systems section of our website for more information on this clamp. More info about SnoRail™ and SnoFence™.

What profiles will the S-5-B fit?

The S-5-B (Brass) is limited in use to traditional double-folded copper standing seam profiles, and traditional folded batten seam profiles. More info about the S-5-B.

What profiles will the S-5-E fit?

The “E” is for “European”. This clamp is designed especially for the traditional double-folded standing seam profile that is so popular all over Western Europe. It is also used here in the U.S., and known by many different names. More info about the S-5-E.

What profiles will the S-5-T fit?

As the “T” suggests, this clamp is especially designed for seam profiles which resemble the letter “T” in their cross-section. Those include (Centria/RollCom) SRS-3, SRS-2, SDP-250, (IMETCO) Series 300, (Inland Buildings) standing seams and (Garland) ArmerSpan. More info about the S-5-T.

What profiles will the S-5-U fit?

The “U” stands for “universal”. This is, by far, our most popular and most versatile clamp. It will fit about 85% of the standing seam profiles manufactured in North America, including most structural metal building type profiles, as well as most of the popular architectural profiles. It can be used on vertically oriented seams and, by rotating the clamp 90°, it can also be used on most horizontal seam profiles as well. More info about the S-5-U.

What profiles will the S-5-Z fit?

The S-5-Z will fit “bulb” seam profiles, such as Zip Rib, BEMO, similar Morin profiles and Berridge Cee-Lock in North America. In Europe, similar profiles are called KalZip, Bemo SS, CFSS, EuroSeam and MegaRoof. More info about the S-5-Z.

What About Thermal Movement?

Thermal movement can affect clamp placement. Standing seam metal roofs are designed to respond thermally with dimensional change along the length of the panels. This is accomplished at the panel-to-attachment clip interface.

Most pre-engineered metal buildings utilize dual component clips. The top portion moves thermally with the panel as it is clamped tightly into the seam, while the lower portion (fastened to structure) is stationary; the two pieces are joined with a slip joint.

When attaching to this type of standing seam metal roof, the S-5! clamp can be attached at a clip location or between clips.

Other standing seam metal roofs rely on differential movement between roof clips and roof panels to accommodate thermal cycling. When installing the S-5! clamp on this type of standing seam metal roof, the clamp locations should avoid the panel’s attachment clips.

How Is S-5!® different from other setscrew-based systems?

Designing a special screw for our S-5! product lineup was only the beginning. We then conducted ASTM B-117 salt spray weathering tests on panel seam specimens to determine whether these screws caused any damage, however slight, that could result in premature corrosion. After 1,000 hours in the salt chamber, no corrosion was detected at any of the setscrew locations! In fact, S-5! offers the only setscrew-based attachment system on the market that puts neither your roof nor your roof warranties in jeopardy!

We also use the highest quality (18-8) stainless steel alloys for all S-5! hardware, and include auxiliary stainless mounting bolts and washers with each clamp to assure longevity and metallurgic compatibility—no matter what the attachment application.

S-5! attachment technology has been in use on rooftops since 1992. Over the years, it has come to be recognized, recommended and even distributed by leading metal panel manufacturers the world over—many of whom will approve no other method for rooftop ancillary attachment.


Our setscrews are designed to dimple the seam material without puncturing, scratching or harming it.