Snow guards and metal roofs 101

Proper snow guard specification techniques
Snow guards can appear in several places of the finished specification, and it is usually the specifier’s choice and preference where they wish to list them. The options for MasterFormat include:

  • 07 61 00–Sheet Metal Roofing;
  • 07 72 00–Roof Accessories;
  • 07 72 53–Snow Guards; and
  • 13 34 19–Metal Building Systems.

When developing a specification for snow guards, there three key elements to request the subcontractor provide in the submittal package:

  • shop drawings of the planned installation;
  • snow guard engineering calculations; and
  • evidence of third-party lab testing.

It is important to detail the specific attachment fastener type in the product description to ensure the snow guard is installed with non-penetrating round point fasteners to protect the integrity of the metal roof warranty. For example,

Set screws: 300 Series stainless steel, 18-8 alloy, 3/8 inch diameter, with non-penetrating round head point.

The creator of the specifications should make sure the building owner is provided with the best options to protect the building occupants and pedestrians, the property around the building and the building itself from the harm of falling ice and snow. The inclusion of properly planned, calculated, and tested snow guards will provide the building owner many years of trouble-free satisfaction while limiting both the owner’s and designer’s liability for injury and harm.

SPECIFICATION EXAMPLE
A. Action Submittal:1. Shop Drawings: Include roof plans showing locations of snow guards on roof and attachment details and spacing.

2. Product Data:
 – Product description.
 – Construction details.
 – Material descriptions.
 – Individual component dimensions.
 – Finishes.
 – Installation instructions.

3. Samples:
 – Clamp samples.
 – [300-mm] 12-inch long cross-member samples including all associated hardware.

B. Individual component dimensions:
1. Include calculation of number and location of snow guards based on designed roof snow load, roof slope, roof type, components, spacings, and finish.
2. Test results: Results of product tensile load testing, issued by a recognized independent testing laboratory, showing ultimate load-to-failure value of attachment.

358d108Harry J. Lubitz, CSI, CDT, is the architectural and national accounts manager for S-5! Metal Roof Innovations, of Colorado Springs, Colorado and S-5! Canada in Ajax, Ont. Lubitz works with the design community to develop and improve architectural specifications for metal roofs and attachment systems. He has more than 25 years of experience in the building materials industry and is active in numerous architectural and professional organizations. He can be reached via e-mail at hlubitz@S-5.com.

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  1. There is definitely a duty of care to the public and visitors to a property if snow fall is likely. Otherwise there is no need to clear the roof unless the depth is ‘exceptional’.
    There is a cinema near us and the metal roof regularly deposits sheets of ice on to the pavement. But they don’t do anything about it.

  2. Thank you for this informative article, Harry. Can you also comment on the risks, if any, resulting from the retention of snow on the roof resulting from the use of snow guards? Assuming the snow guards do their job, retaining snow on the roof, the weight of snow will increase during the winter season. At what point would it be necessary to manually clear the snow from the roof in order not to exceed the roof’s weight bearing capacity?

  3. Roofs are designed to withstand a specific “Designed Roof Snow Load” based on the Building Code which should be used to design and snow guard for a roof. A properly designed snow guard system will take into account essential factors such as, pitch of the roof, the length of the panel or ridge to eave distance, the eave run or assembly length of the snow guard, the Designed Roof Snow Load, and the distance between standing seams. By using these factors you can anticipate the snow load sliding down the roof and how many rows of snow guards you may require, which if multiple rows of snow guards are required will break up the overall load into smaller loads across the roof – so to speak. In the end, the snow load will always be on the roof until the friction between the snow and roof is no longer present. This can happen when the temperature rises and causes the snow to melt along the panel which then reduces the friction, and therefore causes the snow to slide down the roof.

  4. If my neighbor’s roof sheds ice and snow on my property causing a safety concerns for my family and I. What are my next step to getting this resolved.

    1. First talk with them about our concerns , if that does not work check your local bylaws. Speak with someone from your township. If all else fails contact a lawyer

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