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What Causes the Need for Commercial Metal Roof Repair?

Metal Roof Leaks…What Are The Causes?

Mistakes in the design and installation of a new metal roof are sources of major problems. Typically the areas where problems occur are not in the system selection. The majority of the problems that cause metal roof leaks and the need for commercial metal roof repair are related to the details used to finish the metal roof system. These mistakes are not immediately evident after the installation. They may take time to develop.

Here are five of the most frequent problems encountered during a metal roof condition assessment.

Openings in the Horizontal Seams

It is difficult and sometimes not possible to make metal roof panels that extend the full rafter length of the building. In some designs the project designer will limit the length of the panels based on expansion and contraction.

As a result of the restriction on panel length, the installer has to install horizontal seams into the roof system. These horizontal seams run perpendicular to the standing seams in the metal roof.

Horizontal seams are prone to separation over time. In hydrostatic metal roof systems, this can create an opening that allows water to enter back into the building.

Openings in Penetration Flashing

Commercial Metal Roof Reopair CompaniesMetal roof systems are prone to expansion and contraction. This is a result of the metal panels moving because of temperature changes. This movement creates stress at points of attachment as well as at the penetrations through the roof system. The stress leads to the breakdown of the flashings at the penetrations which results in roof leaks.

Metal roof systems are constructed by attaching individual metal panels together at the seams. Once the metal roof systems are installed they are very difficult to remove and disassemble.

Unlike an asphalt shingle system they do not disassemble to allow for a repair of penetration flashing. This makes long-term repairs more difficult to address especially if the penetration is installed after the metal roof is installed.

Commercial Metal Roof Repair Companies With Needed Experience

Metal Roof Oxidation

Metal roofs are made from a wide variety of materials. These include steel, aluminum, tin, copper and zinc. Some of these materials are subject to oxidation. Most metal roof panels are made from sheet metal that has been coated with a protective surface. Over time this coating can wear away leaving the metal panels to oxidize.

Surface oxidation can lead to problems. These problems can include structural failure if the metal roof system is a structural system. Oxidation also impedes repairs. Metal panel oxidation at exposed fastener heads can make sealant application difficult.

Fasteners Backing Out

Metal roof systems typically include a combination of exposed and concealed fasteners. These fasteners can be nails or screws. Exposed fasteners typically have a neoprene washer that seals the fastener head to the surface of the metal roof panel.

Overtime fasteners have a tendency to back out of their seated position. This can be for various reasons. Wind uplift can lead to fastener back out. Metal panels will vibrate under wind conditions leading the fasteners to back out. Freeze-thaw can also lead to fastener back out. As the neoprene washer dries out water can enter in. In winter time conditions the water can freeze and expand leading to the fastener back-out.

Open Ridge/Headwall Flashing

Roof systems need to terminate into other conditions on the surface of the building. These conditions include rising wall details where the roof system matches into other surfaces. An example of this would be a metal roof system ending into a rising wall below a sign band on a shopping center.

This is an area where weakness typically develops. In many cases it is because of poor detail from the original installation. These details require closure strips to prevent water from blowing back into the detail. Contractors may forgo the installation of this closure strip. Initially the underlayment waterproofs the roof system against the blow-back. As the underlayment ages moisture can penetrate into the roof system.

There are other sources of potential metal roof leaks. These five are very common sources that can be checked initially. Knowing where to look for potential leaks is only half of the battle.

Armadillo Roofing & Exteriors, (512) 333-7663, provides commercial metal roof restoration, commercial metal roof repair and commercial metal roof replacement services to Austin, Texas and the surrounding area cities. When you need help with your commercial metal roof, call us. Or, you can check out our sister site at

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