Monthly Archives: May 2013

Seam Mounted Snow Guard Pitfalls

By Brion P. McMullen, Bio

We are often asked about seam-mounted snow guards and our opinion on their effectiveness.  These are individual pad style guards that mechanically fasten to standing seams with set screws.  They can be made of polycarbonate, aluminum, steel, or cheaper die cast versions as well. While they initially seem like a great option due to simplicity and ease of installation, they have some serious drawbacks.

We have tested and observed these types of devices for decades and will never sell or recommend them.  We have been called upon to replace countless snow guard systems, many of which have been the seam mounted style.  Field testing has proven that these guards are very ineffective at preventing snow and ice from sliding down roofs and can possibly damage the seams if impacted hard enough.

Pic of Seam Mounted Snow Guard Damage

Seams Damaged by Sliding Ice and Snow

Snow and ice settles to the lowest part of the panel called the pan.  The most effective method of holding the snow and ice in place is to mount the snow guards in the center of the pan.  If mounted on the seams, the snow and ice is free to simply slide under the face of the guards and off the roof.  Another common problem occurs when a load is placed on one side or the other of a seam mounted guard.  This forces the base to twist and transfer this load to the actual seam.  This has resulted in bent seams, dislodged guards, and uncontrolled snow slides.

Pic of Gutter Damage With Seam Mounted Snow Guards

Gutter Damage With Seam Mounted Snow Guards

If you are looking for a professionally designed snow retention system…then you should call us at 800.SNOJAX.1.  We will create a free custom layout, drawing, and parts list for your project at www.SpacingTool.com.  All of our products are proudly designed, tested, and Made in the USA.

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Snobar vs S-5 Roof Clamp Salt Test

By Brion P. McMullen, Bio

Over the past few years there has been a lot of debate between roof clamp manufacturers about which type of set screw is best for metal roof attachment.  We have conducted a series of tests over the past year showing the differences between the two types of set screws, cupped tip and round tip.  The full video and results can be found at www.TruthAboutSetScrews.com.

We decided to go one step further by initiating ASTM B117 Accelerated Salt Spray Corrosion testing on all of our bar systems, clamps, and our competitor’s components as well.  After 1,006 hours of testing on the first panel, it was removed and disassembled.  Here are some findings from the test:

  1. All attachment point locations of the RoofClamp and SnoBar cupped tip set screws were free of corrosion and rust.  This proves our theory that the cupped tip set screws self seal the attachment point and protect the seam from premature corrosion.
    RoofClamp After 1006 hours of salt testing

    RoofClamp – 1006 hours of salt testing

    SnoBar Clamp After 1006 hours of salt testing

    SnoBar Clamp After 1006 hours of salt testing

    This is contrary to the false claims of our competitor who insists that round tip set screws are the only type of screw that doesn’t cause attachment point corrosion.  Lab testing proved that cupped tip set screws do not cause premature corrosion at the attachment points.

    Panel After Salt Test

    Panel Using SnoBar Clamp After Salt Test

  2. During our video testing at the link provided above we learned how badly the seams are deformed by installing our competitor’s clamps.
    Seam Deformed By The S-5 Clamp

    Seam Deformed By The S-5 Clamp

    After the salt testing was completed we learned more things about our competitor’s clamps.  First, the salt testing proved that this seam deformation over time allows the paint to flake off in large pieces

    S-5 Paint Flaking.

    S-5 Paint Flaking.

    S-5 Paint Flaking.

    S-5 Paint Flaking.

  3. It was impossible to remove the round tip set screws from the competitor’s clamp in order to inspect the attachment point.  The fine thread stainless set screws inside the aluminum clamps have a high failure rate of locking up.  This is caused by two things.  We first discovered this flaw when doing the video clamp testing last year, once we installed and reinstalled the clamps a couple of times, they started to get harder and harder to turn the set screws as the fine threads became clogged with aluminum shavings from the soft clamp threads.  Then after the salt spray testing, we experienced the same problem when the tip on our torque wrench sheared from trying to remove the set screws.  The problem with this defect is that these clamps have a very limited ability to be removed, adjust, re-torqued, or reinstalled once the set screws lock up.  If they were used to install a bar system with round point set screws that eventually slid down the seams, it would be nearly impossible to reset the clamps back to the correct seam location once the set screws were locked up.    The set screws would have to be drilled out or the clamp cut off the seam.

 

In summary, cupped tip set screws for bar mounted snow guards are far more efficient at staying in place on the seam by only requiring 90in/lbs of torque.  Round tip set screws for bar mounted snow guards are far less efficient at staying place and therefore must be highly torque from 130in/lbs to 180in/lbs depending on the gauge of the panel.  This causes seam distortion and can affect the waterproofing seal in the seam which can lead to other issues down the road.  The salt spray test also proves that neither type of screw causes premature corrosion at the attachment point and neither screw should void any paint or panel warranty since they both perform in the same manner. See more test information at www.TruthAboutSetScrews.com.

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