Top 5 Mistakes to Avoid When Placing Screws on a Metal Roof

Mistake #1: Over-tightening the Screws

Overtightening is arguably the most common and destructive mistake made by inexperienced installers. This error can be difficult for a property owner to spot, leading to long-term problems.

The Problem

An over-tightened screw compresses the EPDM washer too much, causing it to deform or “pancake.” It can also create a visible dimple in the metal panel itself. The sound of a screw gun stripping a fastener’s threads is a clear sign that the torque is too high.

Why It’s Damaging

• Compromised Watertight Seal: The EPDM washer is your roof’s primary defense against water intrusion. When over-tightened, the washer loses its ability to flex and rebound with temperature changes, leading to cracks and a broken seal. This creates a direct pathway for water to enter.
  
  
• Panel Distortion: A severely overtightened screw can deform the metal panel, creating a depression where water can pool. This stagnant water accelerates corrosion around the fastener, leading to leaks and rust stains.
  
  
• Thread Stripping: When the screw threads are stripped, the fastener loses its grip in the underlying purlin or decking. This compromises the roof’s structural integrity and ability to withstand wind uplift, a critical factor for any metal roof.
  
  

The Capital City Roofing Solution

Our installers use clutch-driven screw guns set to the precise torque needed to properly compress the washer without damaging the metal panel. We train our crews to tighten each screw until the washer is snug and flush, ensuring a perfect, long-lasting seal.

Mistake #2: Under-tightening the Screws

While over-tightening gets a lot of attention, under-tightening is an equally risky mistake that leaves your roof vulnerable.

The Problem

An under-tightened screw leaves a visible gap between the screw head and the metal panel. The washer appears loose and uncompressed.

Why It’s Damaging

• No Watertight Seal: Just like an overtightened screw, an undertightened screw fails to create a proper seal. The loose washer doesn’t compress against the metal panel, leaving a tiny gap for water to seep.
  
  
• Vibration and Movement: A loose fastener allows the metal panel to shift and vibrate in the wind. This constant movement can cause the screw hole to widen, further compromising the seal and increasing the risk of leaks. This could impact dozens of panels for a large-scale commercial roofing project.
  
  
• Wind Uplift Risk: Loose fasteners are a primary cause of wind uplift. During a storm, the wind can get under a panel and easily lift it, causing it to detach from the roof structure. This poses a significant safety risk and can lead to catastrophic damage.
  
  

The Capital City Roofing Solution

Our methodical process ensures that every screw is secured to the correct tightness. We perform thorough quality checks to confirm that each fastener provides a secure mechanical connection and a durable waterproof seal.

Mistake #3: Placing Screws in the Wrong Location

The placement of screws is not arbitrary; it follows a deliberate pattern designed to maximize durability and weather resistance.

The Problem

The most common location mistakes include:

• Screws in the “Pan” vs. the “Rib”: Screws are often incorrectly placed in the flat part of the panel (the “pan”) instead of the raised ridge (the “rib”).
  
  
• Placing Screws in Valleys or Low Spots: This error places the fastener in a direct water flow path.
  
  
• Improper Spacing: Screws that are too far apart compromise the roof’s ability to withstand wind loads.

Why It’s Damaging

• Accelerated Corrosion: When screws are placed in the pan, they are constantly exposed to standing water, which accelerates the corrosion of both the screw and the metal panel, leading to rust stains and leaks.
• Wind Uplift and Structural Instability: Improper screw spacing can fail to provide adequate holding power, especially for large, uninterrupted spans of a commercial roofing Austin project. This leaves the roof vulnerable to uplift.
  
  
• Compromised Aesthetics: While function is key, incorrect spacing also looks unprofessional and detracts from the clean lines of a new metal roof in Austin, TX.

The Capital City Roofing Solution

We adhere to strict manufacturer guidelines and industry best practices. Our crews are trained to place fasteners on the flats of the panels in a precise, consistent pattern, ensuring a secure attachment and excellent water shedding. We know where to place screws to maximize the roof’s durability and prevent water intrusion.

Mistake #4: Using the Wrong Type of Screw

Not all screws are created equal. An inferior or incorrect fastener can be a fatal flaw in a metal roof installation.

The Problem

Common errors include:

• Using screws with a low-quality or non-UV-resistant washer that will crack and fail in the harsh Texas sun.
  
  
• Using screws with improper threads for the decking material (e.g., wood screws for metal purlins, or vice versa).
  
  
• Using screws with an incompatible coating that will rust or cause a corrosive reaction with the metal panels.

Why It’s Damaging

• Leaking and Fastener Failure: A cheap or inappropriate washer will degrade quickly, leaving an unsealed hole. A screw that doesn’t properly grip the underlying structure provides no holding power.
  
  
• Corrosion and Staining: Using non-galvanized or non-coated screws can lead to rust, which not only looks terrible but can also compromise the integrity of the fastener and the surrounding metal panel. This is a common and unsightly issue on many residential and commercial roofing projects.
  
  

The Capital City Roofing Solution

We only use premium, self-drilling, galvanized or ceramic-coated screws with high-quality, UV-stabilized EPDM washers. These screws are engineered explicitly for long-term outdoor performance, providing a lasting seal and durable connection that won’t fail prematurely.

Mistake #5: Failing to Address Existing Issues During Installation

A new roof is only as good as the structure it’s attached to. An inexperienced contractor might simply cover up pre-existing problems instead of fixing them.

The Problem

• Ignoring Damaged Decking: Installing a new metal roof in Austin, TX, over rotten, sagging, or structurally compromised decking is a surefire way to guarantee premature failure.
  
  
• Reusing Old Underlayment and Flashing: These components are as critical as the metal panels. Reusing old, worn-out materials exposes your roof’s most vulnerable areas.
  
  
• Ignoring Proper Sealing: Proper sealing of seams, joints, and penetrations (such as vents and pipes) with high-quality caulk or sealant is often overlooked.
  
  

Why It’s Damaging

• Structural Failure: A new roof on a damaged foundation is a ticking time bomb. The weight and pressure can cause the underlying structure to fail.
  
  
• Immediate Leaks: Old flashing or underlayment that is no longer watertight will lead to leaks as soon as the first rainstorm hits.
  
  
• Water Intrusion: Improperly sealed seams and penetrations create obvious entry points for water, especially in high-wind conditions.
  
  

The Capital City Roofing Solution

We take a holistic approach. Before any new panels are installed, we thoroughly inspect the entire roof deck and replace any damaged sections. We use new, high-quality synthetic underlayment and flashing to ensure a complete, watertight system from top to bottom.

The Capital City Roofing Difference: We Do It Right the First Time

Choosing a contractor with a meticulous installation process is the best way to avoid these costly mistakes. Our team is trained in the latest techniques for metal roofs and commercial roofing projects. We don’t cut corners. We provide a free, no-obligation estimate and deliver honest, transparent service every step of the way.

Conclusion

The screws holding your metal roof in place are more than just fasteners—they are the key to its integrity and longevity. Avoiding the mistakes of over-tightening, under-tightening, improper placement, using the wrong screws, and neglecting existing issues is essential for a leak-free roof. By choosing an experienced and reputable company like Capital City Roofing, you are not just buying a roof but investing in a proven process and the peace of mind that comes with a quality installation.

Don’t risk your investment on inexperience.

Contact Capital City Roofing today for a free estimate on your next roofing project.