What the Metal Roofing Industry Does not want you to know.

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verncannonblog's Blog

Found some interesting information that will help educate the public. The following are definitions from MBMA (Metal Building Manufacturers Association) Metal Building System Manual. The definitions define the 2 basic types of standing seam roof panels.

Metal panel systems that are designed to withstand being submersed in water for a period of time are called hydrostatic panels. Hydrostatic roof details rely on sealant to keep water from infiltrating the joints and seams. Hydrostatic roof details can be used at almost any slope (1/4:12 minimum).


Metal panel systems that are designed to shed water are referred to as hydrokinetic. Hydrokinetic roof details are typically devoid of sealant and rely on water to freely shed over the joints. Hydrokinetic roof details are not to be used on roof slopes below 3:12.

Also found the following information at ehow.com.

Define a Structural Standing Seam Roof
By Ann Salter, eHow Contributor

View original post 348 more words

4 Comments on “What the Metal Roofing Industry Does not want you to know.”

  1. Gary L. Leese says:

    Water-Shedding Roofs

    A water-shedding, or hydro-kinetic roof, also known as an architectural roof, relies on a steep slope to shed rainwater immediately. These roofs typically incorporate the water-shedding capabilities in the architectural design of the roof itself, which gives rise to the term used to describe them. This roof is ideal for buildings where aesthetics are important, because the inbuilt water resistance is less obvious and just as secure.

    Water-shedding roofs need an optimum gradient of at least 3:12 to begin with, which allows the water to run off down to the downspouts and drainage system. Dramatic visual effects are created using low profile standing seam panels with little to no exposed fasteners. The structural design of this style of metal roof is particularly important to provide adequate support for the shape and load of the roof, and installation usually includes an underlayment such as a 30-lb roofing felt or an adhesive-backed ice and water shield.

    This article appears at the website of Whirlwind Steel:


    How can MBCI claim in court that their roof to be water-shedding only but state on their website that the minimum slope is 1/4:12. Is MBCI right and everyone else wrong? Every where I read, a water shedding roof is to be installed on a minimum 3:12 slope. The right people have not seen this information yet.


  2. Gary L. Leese says:

    Trapezoidal Structural Standing Seam Metal Roof Systems
    The snap-together system, Ultra-Dek®, and field-seamed system, Double-Lok®, were designed from concept to completion for strength, durability and weatherability. The standing seams are three inches above the lowest part of the panel, well above the water level as it flows off the roof.

    The rake/gable at both ends of each roof system finish with a 3-inch high standing seam, avoiding the necessity of finishing in the low, flat part of the panel where the greatest possibilities for leaks occur in many other systems.

    Ultra-Dek® and Double-Lok® panels can be installed before or after the exterior walls are in place. All trim is attached after the roof is installed. With a recommended minimum slope of ¼:12, these standing seam metal roof systems can be used on all types of construction, including metal, masonry or wood, for either new construction or retrofit.

    Weather tight Roof Systems
    Special clips are available allowing for thermal roof expansion and contraction during extreme temperature changes. All trim is both weather tight and aesthetically pleasing, giving the roof a nice finished appearance.

    Factory-applied sealant in the panel side lap ensures a tight, secure weather tight lap whether it is a snap-together or field-seamed system.

    NOTE: As with all standing seam metal roof systems, sound attenuation (e.g. blanket insulation) is required between the panel and the substructure to prevent “roof rumble” during windy conditions. Some composite roof systems may require additional acoustical consideration to ensure that thermal vibration noises are isolated from the building’s interior. Contact your architect and/or engineer for proper acoustical design.

    The above is an excerpt from MBCI’s own website stating that their Ultra-Dek has a factory-applied sealant to ensure a tight, secure weather tight lap. I believe they also stated in court that their Ultra-Dek panel does not require a sealant and that it was a water-shedding panel. It also states above that the minimum recommended slope is 1/4:12. We all know that a water-shedding roof needs to have a minimum slope of 3:12. I wish they would make up their minds on what the real truth was. The right people need to see this information and start checking into this.

    More can be read at this location:



  3. Gary L. Leese says:

    The statement below was taken from a very good article I found on the invention of the standing seam roof panel.

    Any deterioration of the sealant in these endlap joints would permit wind gusts to drive water into the joints, causing leakage. At numerous places along the roof, there are areas where two end panels and two adjacent side panels form a four-corner intersection. This area is particularly difficult to seal. Watertightness of the roof has been a recurring problem in standing seam roofs.

    I would say I agree with the above article. I would like to add that if an improper amount of mastic or none at all existed in the panel then this would cause leaks by wind driven rain as well.

    See Below Link To Read More:



    • Gary,
      Thanks for the article. I found this when I read every patent and article on Standing Seam Roofs. The first patent was in the 1890″s. IN fact to show how un-truthful MBCI was from the witness stand the International Code Conference requires that the side laps be water tight under a ponded water test. Per Terry Wolfe MBCI independent engineer that is ASTM 1514 and the precursor to ASTM 2140. AT least that is what he emailed me. Also, the International Building Code Requires that the standing seam be soldered shut or have sealant in the side laps. Gee I wonder why.


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