Metal Roofing Performance

Metal Roofing Performance (Part 1)

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Are metal roofs really that ecological?

Compared to most asphalt shingle roofs, most metal roofs last much longer and perform much better. The key to a long lasting metal roof is proper installation. Even if the installers followed the manufacturer’s recommended installation practice, a roof may fail prematurely if the roof covering was not properly integrated with the rest of the house structure.

The roof covering (the metal or asphalt roof covering) is only part of a roofing system. The rest of the system includes:

  • Vapour barrier
  • Insulation (type, thickness, completeness of coverage)
  • Ventilation (intake, air channel, outlet, air flow balance)
  • Roof support structure (rafters, beams, etc.)
  • Roof deck
  • Roof geometry
  • Roof penetrations and related hardware
  • Underlayment and waterproofing
  • Eavestroughs and water-channeling system and
  • Roof covering (with related flashings, fittings, etc.)

Although the roof covering gets the attention, the various elements working together as a whole will determine the performance you can expect from it. Changing the roof covering is only one aspect of ensuring that the roof performs as it should.  Unfortunately, roofing products do not have a very deep understanding of how the various elements interact, therefore they do not give the homeowner a quotation that reflects all the work needed to truly integrate the covering with the structure.

For example, a very common complaint of homeowners in Calgary is the formation of ice dams, causing leakages.  The “solution” often proposed is the installation of a metal roof which, according to the salesman, will allow the snow to slide off, and eliminate the ice damming.  While that is true, it doesn’t tell the full story.  The effectiveness of this “solution” depends on the roof geometry, the location of entries to the home, the additional work done on insulation and ventilation, and the protection installed to prevent dangerous snow avalanches in sensitive areas.  The “solution” can cause more problems than it solves if it is not properly designed for the particular structure and its environment.

In the above scenario, the underlying cause of leaking is the lack of sufficient insulation and poor ventilation. Solving that particular problem will also take care of the ice-damming issue.  By reducing the heat lost through the attic and roof, this approach is actually a “green” solution.

Stay tuned for the second part of this article where we’ll be taking a look at common bad practices and how to install a “green” metal roof properly!

Renoteck has extensive experience with metal roofs in Western Canada. If in any case you believe that the integrity of your metal roof is less than optimal, all Renoteck roofs are backed by a lifetime transferable warranty. What’s there to lose? Contact Renoteck today at 1-877-235-9224.