How To Find (& Fix) A Leak In A Metal Roof

Metal roofs have gained increased popularity, thanks to their energy efficiency, longevity, and durability. However, it doesn’t mean that these roofs are immune to leaks and damages. A metal roof is created to allow water flow and not proof. When it ceases to carry out these functions, there is a high chance of experiencing a leak.

Leaks in metal roofing can be hard to trace. To find leaks in a metal roof, search throughout the home to see signs of water spots, mildew, water damage, or cracks around pipes. Most often, leaks in metal roofing will occur:

  • around roof penetrations such as plumbing boots or roof vents
  • along roof transitions, such as valleys or pitch changes
  • along roof to wall intersections
  • in the metal panels caused by rust, holes, or fastenner failure

If you have attic access, you can follow the water stains to trace the leak. However, it’s not always that simple.

If you’re looking for an in-depth guide in finding and fixing leaks in your metal roof, this article is definitely for you.

How Do You Find A Leak In A Metal Roof?

There are usually areas where metal roofs leak, and focusing on those first is the best way to find that leak in your metal roof.

Finding leaks in a metal roof will be more successful if you focus and know where to check. Even though your roof might be having several profiles, metal roof systems, and types, these guidelines are applicable.

By finding areas of weakness and maintenance, you can now make a specific repair plan. It’s best to rule out the following leak-prone areas first to locate a metal roof leak.

The Roof’s Body

If a metal roof leak happens in another place other than the roof penetration, termination, and transition, it is found in the roof’s body. The leak, therefore, occurs in the metal roofing panel itself. 

You can identify such leaks by conducting a visual inspection of your roofing material. Here, you should check for;

  • Rust in the holes
  • Any puncture holes from debris
  • Loose, missing, overtightened, miss or loose aligned screws
  • A standing seam metal roofing panel that slides down your roof from expansion-contraction

If your roof starts to leak or you want to do preventive maintenance, start the inspection by visual inspection of the whole roof. Always begin with leaks that you can find easily to save time. If you have a steep roof that is dangerous to walk on, you can use binoculars for inspection.

Transitions

Transitions are areas where your metal roof connects to another roof section or ties into a different type of roofing system. Depending on the metal roof you use, these sections can have a varying degree of craftsmanship and detail needed to keep them dry. 

Here, you should focus on the small details, especially in the valleys. The common transitions include: 

You should check for:

  • Miss, loose. Missing aligned screws
  • Missing or gaps in butyl tape or sealant
  • Gaps or lose trims between pieces
  • The integrity of seams where a roofing panel overlaps another

The metals usually overlap by 6” and have a sealant or two continuous beads of caulking between them. 

Termination Details

A termination involves any area that your metal roof ends or stops. It’s the periphery of the structure or home and the counter flashing and trims that hide the ends of your metal panels. 

Common terminations include:

  • Hip cap
  • Ridge cap
  • Coping cap over the wall
  • Counter flashing on walls

Here you should check for:

  • Missing or loose pieces of the hip cap, coping cap, and ridge cap
  • Make sure that water isn’t blowing or running underneath caps
  • Inspect the counter flashing where your metal roof stops at an end wall or terminates into a parapet wall. Check the sealant’s integrity behind counter flashing to apply and substrate beats of your sealant to the top of counter flashing.

It will help if you inspect the roof when there is no ice or snow on the roof and the panels are dry.

Roof Penetrations

Roof penetrations involve areas where vents, mechanical supports, and pipes pass through the metal roof. The areas are common leak spots since they depend on butyl tape, caulking, pitch pan sealer, or sealant to keep water out of your building. The holes in your roof should be flashed in. You should examine the flashing as part of regular preventive maintenance. 

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Common Penetration

  • HVAC curbs
  • Skylights
  • Plumbing vents
  • Chimneys

Here you should check for:

  • Gaps found in metal trims in corners of HVAC curbs
  • Degraded sealant around flashing
  • Cracked seals on flashings 

The caulking, pitch pan filler, butyl tape, and sealant exposed to the elements won’t last as long as the roof. You should therefore check sealants and re-apply them. 

I rarely encounter metal roof leaks that are not located in these areas, but if you’re still unable to find where that leak is coming from, seeking the help of an expert is the next best step.

How Do You Fix A Leak In A Metal Roof?

There are at least 6 steps to fixing your roof. Let’s go through them below:

1. Prepare The Tools You’ll Need

Before you start the process, you’ll require the best tools to complete the task. Here is a list of the tools that you’ll need:

  • Nail bar and hammer
  • Extension ladder
  • Wire brush
  • Fabric shears
  • Paintbrush
  • Urethane roof cement
  • Glass-membrane fabric roof patch
  • Plastic putty knife
  • Metal-roofing base coat
  • 1-inch galvanized-steel screws 
  • One 1/2-inch aluminum screw nails 
  • A cordless drill 

You should have all your tools in a single area to save on time. To fix your roof effectively, you should cover the steps below carefully.

2. Get To The Metal Roof

Here you should use a ladder to get to your metal roof. However, you should ensure that you step lightly to prevent injuries. Avoid stepping on between the row of the nails. 

Before you climb the ladder, check that your safety boots don’t have rocks, dust, or other abrasives that could destroy your roof. Your safety comes first before anything else. 

3. Identify The Source Of The Leaks

If a roof is punctured, the first thing that you’ll see are holes. If there is rusting and debris, your roof will either contract or weaken. It would therefore help to identify rust holes and panels that have been affected by contraction and expansion. 

It will also be best if you inspect seam transition points. These points allow roofs to link with each other. Here, check whether there are any loose or missing screws. You can also inspect the periphery to identify any missing materials. 

4. Remove And Replace The Screws

If you identify loose nails, proceed to loosen them further. You can then replace the removed nail using a 1 1/2 inch aluminum nail. However, there is no need to screw them. 

You should have a hammer for driving the nail. If possible, replace rusty nails using screw nails. If you find it hard to remove rusty nails, don’t force them out. 

Instead, you can make screw holes by applying cordless drills that have screw drill bits. You can then drive a 1-inch screw to end rusting and nail loosening on the roof. 

5. Deal With The Gaps

Contractors normally advise homeowners to remove a damaged metal roof. They understand that even a minor hole can cause significant damage. 

You should apply at least one layer of a roofing base coat. Cover the coat using a fabric that is cut to size. It allows the gap to be read for the application of urethane cement.

6. Re-Apply Roof Cement And Do Away With Loose Caulking

Now that you have prepared every gap for proper sealing and have everything right, it’s time to employ urethane cement for sealing leaks on your metal roof. However, ensure that you have identified all areas that have damaged membranes and sealants. You must also ensure that you’ve applied a glass-membrane fabric roof patch and metal-roofing base coat beforehand. 

You should apply the best urethane cement that suits your metal roof. It would be best if you employed urethane cement on the whole area. A 6-inch extension is enough to seal the gaps and holes effectively.

What Is The Best Sealant For Metal Roofs?

Most of the time, the best roof repair option isn’t a product but skills and knowledge to find the leaks and replace the roof.

However, after finding the leak on your roof, it would be best to apply the correct sealant on the market to stop further roof leaks. If you use the wrong sulking or sealant on your roof, you’ll experience flexibility and adhesion problems.

Let’s look at the best sealants that you can count on if your roof is leaking.

Titebond Metal Roof Sealant

Titebond is by far the best product that we use mainly for metal roof repair and maintenance tasks. It is also key for new metal roof installs. It boasts an excellent adhesion for gal-velum and Kynar painted metal roofing. 

Titebond sealant also keeps a weather-tight bond to the roof through contraction and expansion cycles. It’s consistent even in cold weather and sticks well to dirty and damp surfaces. 

NovaFlex Metal Roof Sealant

NovaFlex is also among the best metal roof sealants that you can use to repair leaks. The product is comparable to Titebond and has similar qualities and attributes. However, NovaFlex is the better option for sealing gutters. 

You can use NovaFlex for both commercial and residential guttering jobs. The sealant isn’t as thick as regular roof sealant; thus moves and spreads in joints between metal pieces. In the process, it creates a consistent, watertight gasket. 

NovaFlex is also the best solution when you want to top caulk joints in metal guttering pieces. You can use it on copper, aluminum and Kynar painted metal with excellent success. 

However, after applying the metal roof sealants, ensure that you rivet the joints and trims immediately. You’ll have a difficult time if you let the sealant dry before riveting it. 

The Butyl Tape

Butyl tape is a tried and tested metal roof sealant. It is mainly employed in creating a gasket between metal trim pieces. You can use it on Z, closure, and offset cleat. It is the best option in such applications because of its sticky nature. It also holds metal trims in place while screwing them. 

What Would Cause A Metal Roof To Leak?

Surface rust: Rust is known to peel the roof’s coating, thus leading to scaling and holes. It, therefore, causes significant structural damage. However, just because your roof has rust doesn’t mean it’s leaking. There are several causes of metal roof leaks, as we have highlighted below:

  • Deflection: It is the crimping/creasing or holes of metal panels. The main cause of deflection is foot traffic. It can cause ponding water and, in the end, lead to roof leaks and rust. 
  • Movement: A good metal roof allows water to flow from the roof effectively. If you use a repair product that doesn’t allow proper flexibility, the patch won’t move, thus causing a roof leak. 
  • Incompatible materials: There are specific materials that don’t lead to rust or corrosion. If you use incompatible materials, you’ll get opposite results. 
  • Punctures: HVAC equipment installation and foot traffic are common causes of creases, crimping, and holes. When an HVAC is dragged and hits the roof, there will be punctures and tears. 
  • Fasteners: The two types of attachments for metal panels include fasteners with rubber washers and clips. Sometimes, the fasteners might back out, leaving gaps and holes between the rubber washer and the metal. This will open the roof to water intrusion. 
  • Open laps: If you don’t install the seams along with the metal panels properly, they can lift and open the section for water. The result is structural damage. 
  • Missing parts: With time, some parts of the metal roof can start falling off due to debris, deterioration, and wind. Vent flashings, boots, gutters, downspouts, foam closures, and edge metal can also cause water leaks and intrusion. 

What Is The Life Expectancy Of A Metal Roof?

Most metal roofs have a lifespan of between 40 years to 70 years. However, its longevity may increase or decrease depending on how it is maintained.

A metal roof’s lifespan is higher than other materials, such as traditional asphalt roofing, which lasts for 12-20 years. 

You can improve the lifespan of your metal roof if you install everything correctly and with care. It will also help if you manage repairs effectively and on time. 

Conclusion

A metal roof is created to allow water flow and not waterproof. When it doesn’t allow proper flow, your roof will get damaged, thus leading to a leak. 

However, when you notice any signs of the leaks discussed above, you should quickly find and fix the leaks. Ensure you use the best sealant product to repair your roof. 

If you don’t have the skills and knowledge to fix a metal roof, don’t shy away from contacting a professional. 

Resources:

Pros and cons of metal roofs for your home

How to Find Leaks on Metal Roofs

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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