Metal Roof Leaks: The Dangers of Unaddressed Moisture

Mold spores are in every cubic foot of air, including the ones we are breathing. No worries — most mold is harmless. Yet inside a home, a leaking metal roof can cause harmful mold to spread rapidly throughout your attic and down into your living space. To stop unhealthy mold, you need to have a roofer fix your roof. 

Air is constantly moving through your attic and humidity is at a minimum, mold will have difficulty latching onto surfaces and spreading. Mold needs two things to propagate: A moist, porous surface like sheathing, attic insulation, rafters, and drywall

Black mold — one of the two kinds that can potentially harm your family — can start germinating within 48 hours of landing on a moist surface exposed to slow air movement.

For the first 12 days, mold will not be visible but spread rapidly across surfaces. At around 18 days, mold finally becomes visible as discolorations, black spots, and thin tendrils snaking out across surfaces. If not eradicated quickly (preferably by a mold remediation service, not you), it will spread wherever moisture gives it a chance.

Down through your attic into your ceiling drywall, to your interior walls, across molding, doors, and into wood furniture — mold does not stop spreading on its own. 

The best way to eliminate mold (besides preventing it through annual inspections) is to remove the moisture. Fix roof leaks promptly, so mold never gets a chance to settle and germinate.

Recently we’ve seen an increase in homeowners discovering mold in their home after installing a new metal roof. A leaking roof can cause significant damage to the structural integrity and safety of your home and pose health risks due to mold growth if left unaddressed.

Common Causes Of Metal Roof Leaks

Improper Installation

One of the most common causes of roof leaks is improper installation. When roofers do not follow the proper procedures, it can lead to gaps and seams that allow water to seep in. This can happen for a variety of reasons, such as:

  • Using the wrong materials
  • Not following the manufacturer’s instructions
  • Improper flashing
  • Inadequate ventilation
  • Poor workmanship
Loose or Missing Screws

Metal roofing screws fasten down the panels and trim of your metal roof. If these screws are left loose or missing, water can penetrate through the seams and lead to leaks. To fix this, inspect all the screws on your roof for tightness, replace any missing screws, and use caulk around each screw head if needed.

Old or Worn Sealants 

When a metal roof is constructed, metal roof sealants are typically less durable than metal roofing panels and must be updated as part of routine roof maintenance. When they deteriorate, sealants under trimmings like metal ridge caps and Z flashings around roof transitions, counter flashings, reglets, and pitch pans will occasionally need to be filled up. 

Curb Flashings

A roof curb is an elevated frame attached to a building’s roof and meant to support roof-mounted features and equipment such as skylights, HVAC units, and hatches.

Roof curbs can be fitted to existing units or built from the ground up. They are designed to cover and support items that mount above the roof and pierce its surface. If these flashings are poorly installed or not properly sealed with caulk, they can create gaps that will cause leaks in your metal roof.

Seams & Over Laps

Seams occur when two pieces of metal overlap but don’t fit perfectly together – leaving gaps for water penetration. Overlaps occur when two pieces meet without overlapping – creating a gap that allows water into the home through small spaces near the joint where two sheets come together. 

Stack Flashings

Stack flashings are covers that protect any protrusions, such as chimneys or vent pipes. The area around stack flashings is another region on a metal roof extremely prone to leaks. If the flashing becomes damaged or deteriorates, it can create a gap where water can enter. They should be inspected periodically for signs of rusting or wear & tear. You should then repair/replace it as needed.

Fastener Issues

Metal roofs rely on fasteners to keep them secure at all times. These fasteners are typically screws or nails that hold down the panels to create a watertight seal. Over time, however, these fasteners can become loose due to vibration or harsh weather conditions.

Other typical roofing screw problems include:

  • Screws that are driven from below
  • Screws that have been over-driven
  • Screws that are misaligned

If left unchecked, this looseness can cause water to seep through the gaps created by the loose fasteners, resulting in a leaky roof. 

Rust and Corrosion

Another common cause of metal roof leaks is rust and corrosion. This usually occurs when moisture accumulates on the roof’s surface over time due to poor ventilation or inadequate drainage systems. 

Damage From Severe Weather

Metal roofs are also vulnerable to severe weather conditions such as hail storms or high winds. Such conditions can easily damage exposed metal roof areas without proper protection, such as gutters or an overhang system that deflects debris away from your property line. 

If you think that your roof may be leaking, it is important to have it inspected by a qualified roofer. They will be able to identify the source of the leak and recommend the best course of action for repair. Once the leak is repaired, contact Bio Pro Mold for a whole home inspection to determine the radius of the damage.

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