The Real Problems With Metal Roofs

We don’t install metal roofs — but we repair a lot of problems caused by them. And most of those issues don’t come from the metal itself… they come from shortcuts, poor planning, or sloppy installs.

The #1 problem: Installing over bad shingles

One of the most common shortcuts we see is metal roofing installed directly over old, failing shingles.

On paper, it saves time and dump fees. In reality, it hides problems that don’t go away:

• Rot in the roof decking
• Moisture trapped between layers
• Uneven surfaces causing panel distortion
• Hidden leaks continuing underneath

Once that metal is on top, diagnosing or fixing anything underneath becomes much harder and much more expensive.

Fastener failure and leaks

Most metal systems rely on hundreds — sometimes thousands — of exposed fasteners.

Over time, we regularly see:

• Rubber washers cracking and failing
• Screws backing out due to expansion and contraction
• Improper fastening into weak or rotten decking

Every failed fastener is a potential leak point.

Condensation and moisture problems

Metal roofs conduct temperature rapidly. In our Nova Scotia climate, that leads to heavy condensation problems when not properly designed.

If ventilation and underlayers aren’t done correctly, moisture gets trapped — leading to:

• Mold in attic spaces
• Rust underneath panels
• Plywood and roof deck rot

Noise and thermal expansion

Homeowners are often surprised how loud some metal roofs can be during rain, wind, or snow slip.

And because metal expands and contracts with temperature swings, we often see:

• Oil-canning (visible panel warping)
• Fasteners loosening over time
• Panels shifting or creaking

Not ideal for every roof

Metal roofs aren’t necessarily bad — but they’re not right for every house. Certain roof slopes, structural designs, and shaded properties make them a poor long-term choice.

Unfortunately, some installers will sell them anyway.

What we see most often

• Leaks around fasteners and seams
• Poor flashing transitions
• Hidden rot underneath overlays
• Condensation damage inside the attic

Most of these come down to one thing: poor installation standards.