Common Steel Roofing Mistakes to Avoid

What Goes Wrong With Steel Roof Installation?

Steel roofing installation errors are more consequential than asphalt errors because they are harder to identify and more expensive to correct. Here is what goes wrong and how to avoid each failure.

Mistake: Felt Paper Underlayment Under Metal

How to avoid it: Standard felt paper is not recommended beneath metal roofing because it can trap moisture that accelerates corrosion at the panel underside and in some cases off-gases compounds that degrade certain metal coatings. Metal-specific self-adhering or synthetic underlayment is the appropriate product. Ask any metal roofing contractor specifically what underlayment product they are using and confirm it is rated for metal roofing applications. (For more on this, see Questions to Ask a Metal Roofing Contractor.)

Mistake: Improper Panel Overlap and Seaming

How to avoid it: Exposed-fastener panels require correct overlap to prevent water infiltration at panel edges. Standing seam panels require proper seam engagement and rollforming to lock panels correctly. Both are skill-dependent operations that inexperienced crews execute incorrectly, producing systems that leak at the first heavy rain. Verify that the crew has specific metal roofing experience and can provide local references from completed metal installations. (For more on this, see How to Find the Best Metal Roofing Contractor.)

Mistake: Galvanic Corrosion From Incompatible Metals

How to avoid it: When dissimilar metals contact each other in the presence of moisture, galvanic corrosion occurs. Steel roofing panels in contact with copper flashing or copper-containing materials corrode at the contact point. Use compatible metals for all flashing and trim. Confirm compatibility before installation begins.

Mistake: Not Accounting for Thermal Movement

How to avoid it: Steel expands and contracts significantly with temperature changes. Standing seam systems use floating clips for thermal movement. Exposed-fastener systems must use fasteners with rubber washers and oversized holes that allow movement. Improper fastening that restricts thermal movement produces oil-canning (visible waviness in panel fields) and eventually panel failures. An experienced installer accounts for thermal movement in the fastening approach.

Mistake: Installing Metal on Insufficient Slope

How to avoid it: Most exposed-fastener steel panel systems require a minimum slope of 3:12 for proper water shedding. Installing on a slope below the system’s minimum requirement causes water to pond at seams and penetrations, leading to leaks. Confirm the panel system is rated for the roof’s actual slope before ordering materials. (For more on this, see What Affects the Cost of a Steel Roof?.)

Getting It Right

Metal-appropriate underlayment, correct panel overlap and seaming, compatible metals, thermal movement accommodation, and appropriate slope-to-system matching are the elements that determine whether a steel roof performs for 40 to 70 years or fails within a few years. Connect with a metal roofing specialist below.

Working With a Contractor on This Project

Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.

Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.

Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project.

Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.

Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.

Making a Confident Decision

The information in this article is designed to help you ask better questions of the professionals you work with, evaluate their answers with more confidence, and understand the decisions involved in this type of home services project. It is not a substitute for professional assessment of your specific home.

Every home is different. Roof slopes, local weather, tree exposure, soil conditions, and existing system condition all affect what the right solution is for your specific situation. The general principles here apply broadly, but a professional who assesses your home in person will give you guidance that accounts for the details that general articles cannot.

When you are ready to move forward, getting at least two or three quotes from licensed, insured, local contractors is the most important practical step. It lets you compare approaches, assess contractor quality, and confirm that the solution proposed matches your specific situation and budget.