6 Best Roofing Nails for Securing Flashing Pros Use

Securing flashing is the unsung hero of a roof system, acting as the primary defense against water infiltration at the most vulnerable joints. Choosing the wrong fastener can lead to premature corrosion, staining, or a failure that compromises the entire underlayment. While the shingles themselves might look uniform, the integrity of the flashing determines whether a roof lasts ten years or thirty. Understanding which nail to drive where is the difference between a detail-oriented pro and a call-back waiting to happen.

Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!

Grip-Rite EG Roofing Nails: The Go-To Standard

Electro-galvanized (EG) nails are the workhorses of the residential roofing industry. They feature a thin layer of zinc coating that provides baseline protection against rust in standard, dry climates.

For projects where the budget is tight and the flashing is tucked well beneath secondary barriers, these nails are the default choice. They are readily available, compatible with all standard coil nailers, and provide sufficient holding power for basic aluminum flashing.

Avoid using these in high-moisture environments or near the coast. The zinc coating is thin enough that environmental salt or constant dampness will lead to red rust staining on the flashing within a few seasons.

Maze Double Hot-Dipped Nails: For Longevity

When a job requires a fastener that outlives the surrounding materials, hot-dipped galvanized nails are the industry benchmark. The process of dipping the steel into molten zinc creates a thick, durable barrier that resists abrasion during the nailing process.

These nails are essential when installing step flashing or apron flashing that remains exposed to the elements. The thick coating prevents the “bleeding” effect often seen with cheaper fasteners, keeping the roof line clean and professional for decades.

Do not mistake electro-galvanized for hot-dipped. If the head of the nail is smooth and bright, it likely lacks the thickness required for long-term exterior durability.

Pro-Fit EPDM Washer Nails: For Watertight Seals

EPDM (Ethylene Propylene Diene Monomer) washer nails are specifically designed for applications where the nail head must penetrate the flashing surface directly. The rubber gasket compresses against the metal, creating a gasketed seal that prevents water from wicking down the nail shank.

These are mandatory when fastening surface-mounted flashing or metal panel roofing. Without that rubber gasket, every nail hole becomes a potential entry point for wind-driven rain.

When driving these, watch the pressure. Overtightening will deform the rubber washer, breaking the seal, while undertightening leaves a gap that will eventually allow moisture to bypass the gasket.

Simpson 316 Stainless Steel Nails: Coastal Use

Stainless steel is non-negotiable within five miles of the ocean or in areas with high airborne chemical pollutants. Grade 316 stainless offers superior resistance to pitting and chloride-induced corrosion, which will eat through standard galvanized nails in months.

The cost is significantly higher, but the investment is minor compared to the cost of replacing rusted flashing that has stained an expensive cedar or metal roof. These are the “install it and forget it” solution for high-end residential builds.

Always use 316 grade rather than 304 if the roof is near salt water. The added molybdenum in 316 grade provides the necessary chemical stability to survive harsh, corrosive marine environments.

Hillman Group Aluminum Nails: For Metal Flashing

Aluminum nails are designed to be chemically compatible with aluminum flashing. When two different metals touch in the presence of moisture, galvanic corrosion occurs, causing the less noble metal to disintegrate.

Using aluminum nails on aluminum flashing ensures that both materials corrode at the same rate or not at all. This eliminates the risk of a “sacrificial” fastener failing prematurely while the surrounding metal remains intact.

Aluminum is a softer metal, so these nails are prone to bending if struck too hard. Use a consistent, controlled depth setting on your nailer to avoid snapping the heads off during installation.

Solid Copper Nails: For Copper Flashing Only

Copper is an aesthetic and functional choice for luxury roofing, but it demands strict material discipline. Using steel or even galvanized nails with copper flashing will trigger rapid galvanic corrosion, creating holes in the copper in short order.

Solid copper nails provide the same life expectancy as the flashing itself. They will develop a natural patina over time, blending perfectly with the surrounding metal rather than standing out as a bright, corroding blemish.

Keep in mind that copper is soft and lacks the shear strength of steel. These are meant for light-gauge flashing and should never be used to fasten structural components or heavy-gauge metal systems.

Matching Nail Metal to Your Flashing Material

The rule of thumb is simple: match the metal of the nail to the metal of the flashing. This prevents the electrochemical reaction known as galvanic corrosion, which is a common culprit in “mystery” leaks.

• Aluminum Flashing: Use aluminum or high-quality stainless steel nails.
• Copper Flashing: Use only solid copper nails.
• Galvanized Steel Flashing: Use hot-dipped galvanized or stainless steel nails.

If you ever find yourself in doubt, stainless steel is the universal neutralizer. While more expensive, it is compatible with almost every metal roofing material without triggering a reaction.

Choosing the Right Nail Length and Shank Type

Nail length is determined by the flashing gauge and the thickness of the substrate underneath. A minimum of 3/4-inch penetration into the roof deck is required for structural stability, but ensure the nail isn’t long enough to poke through the underside of exposed soffits.

Regarding shank type, ring-shank nails are superior to smooth-shank nails for almost every roofing application. The circular rings act like barbs, increasing the force required to pull the nail out as the roof deck expands and contracts.

Avoid smooth-shank nails for flashing, as thermal movement in the roof system will cause the nails to “back out” over time. A nail that backs out even an eighth of an inch can lift the flashing and create an entry point for water.

Proper Nailing Technique for a Watertight Seal

Precision is just as important as the choice of fastener. Always drive the nail head flush with the surface of the flashing; never countersink it, as this can crack the metal or tear the coating, inviting rust.

If you are nailing through the face of the flashing, ensure the fastener is placed in a location where water naturally sheds away from the hole. Always use a small dab of high-grade roofing sealant under the head of the nail if you are forced to use an exposed fastener in a low-slope application.

Never place nails in a way that restricts the natural thermal expansion of the metal. If the flashing is long, account for movement by using slightly oversized holes or strategic fastening points that allow the metal to slide.

Code & Climate: When to Use Stainless Steel

Local building codes often dictate the minimum requirements for fasteners, but code is just the legal minimum, not the recommended standard. In climates with high humidity, frequent freeze-thaw cycles, or heavy snow loads, go above and beyond the code.

If you are working in a climate where ice dams are common, stainless steel is a wise insurance policy. The constant expansion of ice and water can weaken the integrity of cheaper galvanized coatings, leading to failure right when the roof is under the most stress.

If your regional building code mandates hurricane ties or specific uplift ratings, ensure your chosen nails meet those tensile strength requirements. A roof is only as strong as its weakest connection, and in a high-wind event, that connection is often the flashing fastener.

The longevity of a roofing system is dictated as much by the tiny fasteners holding the flashing in place as it is by the quality of the shingles or panels installed. By aligning your nail choice with the specific metal of your flashing and the environmental challenges of your region, you ensure that every roof edge remains secure and leak-free for the long haul. Take the time to spec the right hardware; it is the most cost-effective way to protect the integrity of your work.