Repair Metal Building Roofs

Most chronic leaks on metal building roofs in Nassau County aren’t holes in the metal. They’re failures where two panels meet-at laps, at fasteners, at the ridge or eave-or where the roof transitions to a wall, curb, or penetration. I’ve tracked leaks in auto shops, warehouses, and self-storage facilities where the owner has bought cases of sealant, yet every hard rain still drips over equipment, stock, or tenant units. The reason is simple: sealant alone doesn’t address thermal movement, panel overlap mechanics, or loosened attachments. A structured repair approach-inspecting every fastener line, every seam, every flashing, and every structural connection-stops the leaks and protects your operations.

Let’s walk through what typically goes wrong on metal building roofs in Nassau County, what TWI Roofing’s repair process actually includes, and how to decide whether repair, restoration, or full replacement makes sense for your building.

What Kind of Metal Building Roof Do You Have?

Before you can plan a repair, you need to know your system. Most metal buildings in Nassau County use one of two basic panel types, and the repair strategy differs for each.

Through-Fastened Panels

This is the classic metal building roof: corrugated, ribbed, or R-panel steel fastened through the panel top into purlins with exposed screws. You can see the fastener heads from the ground. These systems are economical and quick to install, but they rely entirely on the screws and their neoprene washers to keep water out. When those washers dry out or the screws back out-both very common after a decade or two-water seeps in around every loose fastener. If you have a through-fastened roof, most of your leak problems will trace back to fastener lines and panel laps.

Standing Seam and Retrofit Metal Systems

Newer or upgraded metal buildings often use structural standing seam panels that clip to purlins without exposed fasteners. The seams are mechanically locked or rolled together, and the panels can expand and contract without stressing fasteners. Some older buildings have been retrofitted with a standing seam system installed over the original roof. Repairs on these systems focus on clips, seam integrity, end-wall details, and penetrations-not on thousands of screw holes.

Common Problems on Metal Building Roofs

I’ve worked on metal building roofs throughout Nassau County for over two decades. The same issues show up again and again, often in predictable patterns.

Fastener Back-Out and Gasket Failure

Thermal expansion moves metal panels constantly. Wind vibration rattles the roof. Over years, screws loosen or tilt sideways, and the rubber washers under the screw heads crack and shrink. Once the seal fails, water runs down the fastener into the building. On a typical 10,000-square-foot metal building, you might have 5,000 or more exposed fasteners, and a significant percentage of them will be compromised on a 15-year-old roof. These leaks are hard to isolate because water can travel along purlins before dripping inside.

Panel Seams, End-Laps, and Side-Laps

Where panels overlap at their ends (end-laps) or side edges (side-laps), they must shed water downslope without capillary draw or wind-driven rain getting underneath. If the overlap is too short, the seam wasn’t sealed with butyl tape, or fasteners are missing, water pushes into the joint-especially on low-slope roofs where storms generate ponding. On a self-storage facility in Westbury, we found that 80 percent of the leaks were at end-laps that had been installed with no sealant and minimum overlap. The panels were fine; the assembly wasn’t.

Rust, Coating Failure, and Pinholes

Galvanized and painted steel roofs hold up well for years, but exposed fasteners, ponding areas, and damaged finish coats invite rust. Near the coast, salt air accelerates corrosion. Even inland, industrial environments or simply aging paint can lead to rust around fastener lines, at panel edges, and in low spots. Small rust-through holes allow water in, and the corrosion spreads underneath. If you catch rust early-surface oxidation and staining-you can clean, prime, and coat. If the panel has rusted through or thinned significantly, that section needs replacement.

Flashing, Transitions, and Add-On Penetrations

Roof-to-wall flashings, ridge caps, eave trim, and penetrations like skylights, vents, and rooftop HVAC units are chronic leak sources on metal buildings. Many of these details are installed flat against the ribs or simply caulked, which fails quickly. Later additions-solar arrays, exhaust fans, security lighting-are often cut in by other trades who don’t understand metal roof drainage or movement. On an auto shop in Baldwin, the biggest leak wasn’t from the original roof; it was from a roof-mounted air handler that a mechanical contractor set on the panels with foam tape and no curb or structural flashing.

Our Metal Building Roof Repair Process

TWI Roofing’s metal building roof repair service is built around understanding the structure first-not random caulking.

1. Survey and Leak Tracking

We start inside. We map every leak location, follow water stains back toward the likely entry point, and document any insulation damage or structural rust. Then we walk the roof from eave to ridge, checking panel condition, fastener lines, seams, and all penetrations. We photograph everything and build a condition report that shows you exactly what’s failing and where.

2. Immediate Risk Mitigation

If you have active leaks over critical areas-machinery, inventory, tenant spaces-we can install temporary protection while we organize a permanent repair plan. This might be localized sealants, peel-and-stick patches, or protective tarps. These measures are chosen so they don’t interfere with or contaminate the surface when we return for the final repair.

3. Fastener and Attachment Repairs

For through-fastened roofs, we remove loose, stripped, or corroded screws and replace them with new corrosion-resistant fasteners-often larger diameter, always with fresh EPDM or neoprene washers-driven into solid purlin. If the purlin wood is soft or damaged, we may add blocking or sister in new framing. In high-wind areas like the south shore, we sometimes upgrade fastener spacing at edges and corners to meet current uplift requirements. This mechanical fix is the foundation of the repair.

4. Panel Seam and Lap Repairs

We clean all laps, remove old sealant, and re-seal or re-fasten joints with compatible butyl tape or high-performance lap sealants. If the overlap is too short or the fastening pattern is inadequate, we correct it. In some cases, we add closure strips or backing plates to reinforce problem seams. The goal is to restore the designed overlap mechanics so the seam sheds water correctly in Nassau’s wind-driven rain.

5. Flashings, Curbs, and Penetration Re-Detailing

We rebuild flashings around walls, parapets, rooftop units, and penetrations so water sheds onto the roof surface, not behind or under the panels. This often means fabricating and installing new counterflashings, closing rib openings with closure foam or metal closures, and integrating curbs properly with the roof pitch and drainage pattern. On a warehouse in Mineola, we removed four rooftop condensers temporarily so we could build proper curbs and flashings underneath; the units had been sitting directly on the panels for years.

6. Localized Coating and Corrosion Treatment

Where panels show surface rust or coating breakdown, we wire-brush or grind to sound metal, apply rust-inhibiting primer, and coat the repaired areas with compatible acrylic or urethane coatings. This is not a full roof restoration coating; it’s targeted protection for the zones we’ve mechanically repaired. The coating extends the life of the repair and helps tie together seams, fastener lines, and flashings into a unified water-shedding surface.

7. Final Inspection and Documentation

After repairs, we walk the roof again, inspect all treated areas, and check that drains and gutters are clear. Where feasible, we may perform controlled water testing to verify leak elimination. We provide a repair summary with photos, locations, and work performed so you have a clear record for your maintenance files and capital planning.

Repair vs Restoration vs Replacement for Metal Building Roofs

Not every leaking metal building roof needs the same level of intervention. Here’s how to decide.

When Repair Is the Appropriate Scope

• Leaks are localized to specific fastener lines, seams, or details-not widespread across the entire roof field.
• Panels show surface rust or finish loss but are not extensively corroded through or structurally weakened.
• Decking, purlins, and framing are sound, with no significant rot, deflection, or corrosion.
• You need to stop leaks and stabilize the roof now without committing to a major capital replacement project.

On a smaller self-storage building in Hicksville, we repaired fastener leaks and re-flashed roof edges for under $8,000. The roof was only 12 years old, and the panels were in excellent condition. A repair gave them another decade of service.

When to Consider a Full Roof Restoration

If leaks are recurring in multiple areas, coatings are breaking down across most of the roof, and the system shows moderate wear but the structure is sound, a restoration may make more sense. Restoration combines targeted repairs-fasteners, seams, flashings-with a roof-wide protective coating system and, often, a new warranty. It costs more than localized repair but less than full replacement, and it can add 10 to 15 years to the roof’s life.

Clear Indicators for Replacement or Retrofit

When panels are severely corroded, purlins are rusted or rotted, or you have chronic ponding and structural deflection that can’t be fixed with repairs, you’re looking at a new roof system or a metal-over retrofit. At that point, more repair money is wasted. We’ll tell you honestly when you’ve reached that threshold. On a warehouse in Glen Cove, the roof had been patched for 20 years, and the panels were so thin they flexed underfoot. We recommended-and installed-a structural standing seam retrofit over the existing roof, which gave them a brand-new 20-year system without replacing the deck or disrupting operations inside.

Metal Building Roof Repair in Nassau County’s Climate

Nassau County’s weather drives how we approach metal building roof repairs.

Wind Uplift and Edge Zones

Coastal and open-field exposures generate high uplift forces at roof edges, corners, and ridges. These zones often show fastener pull-out, panel flutter, and edge-metal damage first. When we repair a metal building roof in Nassau County, we verify and often upgrade fastener density and type in these critical zones to meet current wind-load requirements-not just fix leaks. This improves storm resilience for the long term.

Salt Air and Industrial Exposure

Near the shore or in certain industrial areas, corrosion happens faster. Repairs must use stainless or coated fasteners, marine-grade sealants, and sometimes replacement sections of higher-grade metal. We factor corrosion rate into our recommendations: if the roof is corroding rapidly, we may advise a larger repair scope or even replacement rather than short-term patching that won’t hold up.

Working Around Operations and Tenants

Most metal buildings house active businesses or tenants. We coordinate repair work to maintain access to loading docks, entrances, and operational areas. Noisy tasks-removing fasteners, grinding rust-are scheduled to minimize disruption. Safety setups, signage, and staging protect people and property while we work overhead. On a multi-tenant self-storage facility, we phased repairs by building section so no tenant lost access during the project.

What to Look For in a Metal Building Roof Repair Contractor

Not every roofer understands metal building systems. Here’s what to ask.

Relevant Experience and System Knowledge

• How many metal building roof repairs have you completed recently, and on what building types-warehouses, auto shops, self-storage, agricultural?
• Are you familiar with my specific panel profile and system-through-fastened vs standing seam vs retrofit?
• Can you explain how you handle thermal movement and expansion joints in metal building roofs?

If the contractor talks only about residential standing seam or treats all metal roofs the same, they may not have the depth of experience your building requires.

Clear Scope, Pricing, and Warranty Terms

A proposal should identify which leaks and areas will be addressed, what repair methods will be used, and what is not covered by the scope. Ask about workmanship warranty length, what constitutes a warrantable leak, and any required maintenance to keep the warranty in force. Vague proposals-“seal all leaks, $5,000”-are red flags.

Frequently Asked Questions About Metal Building Roof Repair

Can metal building roof leaks usually be repaired, or do we need a new roof?

Many leaks can be successfully repaired when panels and structure are still in good condition. An on-site inspection is necessary to determine whether repair alone makes sense or whether restoration or replacement is more cost-effective. If panels are sound, purlins are solid, and leaks are confined to fasteners, seams, or details, repair is usually the right first step.

Will repairs disrupt our business operations?

Most metal building roof repairs are done with operations ongoing. We phase work, use temporary protection where needed, and schedule noisy or high-access tasks during off-hours or slow periods. On multi-tenant buildings, we work section by section to maintain access. Downtime is minimal compared to a full roof replacement.

How long do metal roof repairs last on a building like ours?

Lifespan depends on roof age, environment, and scope of work. Targeted repairs on a relatively sound roof-good panels, solid structure-can last 5 to 15 years. Late-stage roofs with widespread corrosion may see shorter benefit, in which case we’ll recommend a broader solution up front rather than selling you repairs that won’t hold.

Are repairs more economical than full replacement?

Yes, when the roof still has structural life. Repairs are typically one-tenth to one-quarter the cost of full replacement and can be very economical when you’re buying time before a planned capital project. However, if you’re facing major deterioration-rusted-through panels, failed purlins, chronic ponding-refusing to address the bigger issue reduces repair value and wastes money.

Do you repair metal building roofs throughout Nassau County?

Yes. TWI Roofing services metal buildings across Nassau County-warehouses, auto shops, self-storage facilities, manufacturing plants, and agricultural buildings. We’ll schedule a roof inspection, assess the condition, and propose a repair or phased strategy that fits your budget and risk tolerance.

Stabilize Your Metal Building Roof Before Problems Grow

Timely, well-planned metal building roof repairs stop leaks, slow corrosion, and protect your inventory, equipment, and operations without requiring an immediate full replacement. In Nassau County’s windy, coastal-influenced climate, successful repair means understanding the metal system, local exposure, and your building’s use-not just applying more caulk to the same spots every year.

If your metal building roof leaks after every storm, or you’ve been patching the same areas for years, schedule a professional roof assessment. TWI Roofing will identify failure points, propose a repair or phased strategy that fits your budget and timeline, and give you a clear, realistic picture of what the roof needs and how long the repairs should last.

Share your leak history, photos, and any prior repair or inspection reports so we can build a repair plan based on the complete condition of your roof-not guesswork. We’ll tell you honestly whether repair makes sense or whether you’ve reached the point where restoration or replacement is the smarter investment.