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Detecting and Fixing Leaks on Metal Roofs

Effectively detecting and fixing leaks on metal roofs involves targeted efforts and knowing the right places to examine. Although the metal roofing industry includes various types, profiles, and systems, these guidelines will assist you in locating vulnerable or maintenance-required areas, enabling you to devise a customized repair plan.

Metal roof leaks can be categorized into four groups: leaks within the roof’s body, at transition points, at termination details, or surrounding roof penetrations.

Leaks Within the Roof's Body

Detecting and fixing leaks on metal roofs that occur in areas other than transitions, terminations, or penetrations typically involve the metal roofing panel itself. Start your investigation with a visual inspection of the roofing material.

Inspect for:

  • Misaligned, missing, overtightened, or loose screws
  • Debris-caused puncture holes
  • Dust-related holes
  • Displaced standing seam metal roofing panels due to expansion-contraction



Helpful Advice: Commence your inspection with a visual assessment of the entire roof when looking for leaks or conducting preventative maintenance. Progressively narrow your search, beginning with easily detectable leaks. If your metal roof is steep and challenging or dangerous to walk on, perform a ground-based inspection using binoculars.

Leaks at Roof Transition Points

Transitions refer to where the metal roof connects to another section or a different type of roofing system. The intricacy of these areas can vary, so pay close attention to small details, particularly in valleys, as seemingly minor issues might be the source of leaks.

Common Transitions:

  • Changes in pitch
  • Valleys
  • Connections between roof planes of the same or different materials

Inspect for:

  • Gaps between pieces or loose trims
  • Absent or insufficient sealant/butyl tape
  • Misaligned, missing, or loose screws
  • Overlapping metal roofing panel seam integrity



Helpful Advice : Detecting and fixing leaks on metal roofs often involves examining transition areas where trim pieces should overlap by 6″ and have two continuous beads of caulking or sealant between them. You cannot visually confirm the presence of sealant without disassembling the trims. However, you can slide a thin piece of sheet metal between the two trim pieces. If it goes in 6″ or more, the installer might have missed this area, potentially resulting in a leak.

Addressing Leaks at Termination Points

In the process of detecting and fixing leaks on metal roofs, it’s important to pay attention to termination points. These refer to the areas where the metal roofing concludes or terminates, typically found along the edges of a building or structure. These points are covered by trims and counter flashing that conceal the ends of the metal panels.

Typical Termination Points:

  • Ridge cap
  • Hip cap
  • Gable or rake trim
  • Coping cap atop walls
  • Counter flashing on walls

Inspect for:

  • Detached or absent ridge, hip, or coping cap pieces
  • Ensure water is not flowing or being blown beneath caps
  • Thoroughly examine counter flashing where the metal roof terminates into a parapet wall or ends at an end wall. Assess the sealant’s condition behind counter flashing and apply an additional bead of sealant to the top of counter flashing if necessary.

Helpful Advice: When examining a metal roof, perform the inspection when metal panels are dry and devoid of snow or ice. Adhere to these safety precautions for a secure inspection: 1) Secure your ladder to the gutter or roof line to prevent falls. Metal surfaces can be slippery, and ladders may topple over on windy days. 2) If walking in the valley is necessary, be cautious of your steps and avoid stepping directly on hip or ridge caps to prevent permanent dents. 3) Use fall protection for roofs with a pitch over 4/12 and avoid conducting the inspection alone.

Handling Leaks Around Roof Penetrations

Roof penetrations are the points where pipes, vents, and mechanical supports pass through the metal roof. These holes require proper flashing to prevent leaks. Such areas are prone to leaks as they often rely on caulking, sealant, butyl tape, or pitch pan sealer to keep water out. It is crucial to inspect flashings as part of a regular preventive maintenance plan.

Frequent Penetration-Related Metal Roof Leaks:

  • Plumbing vents
  • HVAC units
  • Skylights
  • Chimneys

Inspect for:

  • Deteriorated sealant around flashing
  • Cracked seals on flashings at the junction with the metal deck
  • Gaps in metal trims at HVAC unit corners

Helpful Advice: Detecting and fixing leaks on metal roofs require understanding that sealants, caulking, butyl tape, and pitch pan filler exposed to the elements have a shorter lifespan compared to your metal roof. Regularly checking and re-applying sealants is considered maintenance in the roofing industry. Being aware of this fact will help you effectively manage your metal roof’s performance.

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    Cambridge Roofers provides and installs metal roofing solutions and systems to refurbishment and new build projects throughout Cambridgeshire and London. With a dedication to quality and continuous improvement, Cambridge Roofers Ltd are able to provide only the products available in the industry through constant research and development. 

    As approved installers, our warranties can go up to 40 years with manufacturers endorsement.