Roofing Fasteners: Coil Nails, Cap Nails & Screws for LA Reroofs

A roof is a stack of layers, and every layer is held down by a different fastener. Get one wrong and the failure does not show up on install day — it shows up as a lifted shingle in the first Santa Ana wind or a leak traced back to a nail head that never sealed. Roofing fasteners are also an inspection item: length, pattern and cap type are things a plan checker will ask about. This guide covers what goes where, how long it needs to be, and which of our stock items matches each layer.

Match the fastener to the layer, not to the roof

There is no single roofing nail. Underlayment, shingles, tile and metal panels each want something different, and using a shingle nail on underlayment or an underlayment cap nail on shingles is the most common error we see on a materials list.

Two things that table cannot carry. First, every length in it is a starting point, not a spec: the fastener has to penetrate the sheathing fully or reach a stated minimum into it, so a second layer of underlayment, a thicker deck or a recover job all push the length up. Second, the whole roof has to agree — a correct nail driven into a deck that is too thin is still a failure.

Cap nails: holding the underlayment

Underlayment is a large, light, wind-catching sheet, and a plain nail head simply pulls through it. A cap nail spreads the load over a washer that is part of the fastener, which is why caps are standard for synthetic underlayment and increasingly expected for felt on exposed decks.

The choice inside cap nails is the cap material. Plastic-capped nails such as the #12 x 1-1/2 in. plastic round cap nail and the 2D #12 x 1 in. nail with plastic cap are the everyday option and hold synthetic underlayment well. Metal caps — the #12 x 1 in. metal square cap nail is the version we stock — resist heat and UV better on a deck that will sit exposed longer than planned, which in a summer LA reroof happens more often than anyone schedules for. For gun work, bulk packs like the 3000-piece #12 x 1 in. plastic round cap are how this actually gets bought.

Whichever you use, the pattern matters as much as the fastener. Underlayment blows off at the perimeter and at the laps first, so tighten spacing at edges, and follow the manufacturer's pattern rather than the one that feels fast. Our comparison of synthetic and felt underlayment covers which membrane suits a Southern California roof in the first place.

Coil nails: fastening shingles

Almost all shingle work in Los Angeles is gun-nailed with 15-degree wire-collated coil nails. The 7/8 in. coil roofing nail suits a standard single-layer application over adequate sheathing, the 1 in. coil nail is the common step up, the 1-1/4 in. coil nail handles thicker laminated shingles or an extra layer, and the 1-1/2 in. electro-galvanized coil covers recovers and thicker assemblies.

Length is decided by what the nail has to get through and what it has to end up in — through the shingle, through the underlayment, and fully through or a stated minimum into the deck. Measure the actual assembly rather than reusing whatever was on the truck.

Depth setting is where good material gets wasted. A nail driven flush and square holds; a nail driven proud lifts the course above it, and an overdriven nail cuts through the mat and turns the fastener into a hole. Set the gun pressure on a scrap, check it again after a break, and check it once more when the sun has been on the shingles for a few hours. Nail placement in the manufacturer's nailing zone — not above it — is what makes the wind rating on the wrapper mean anything, and it is worth reading alongside our guide to choosing shingle colors for LA homes.

Hand-drive nails, flashing and repairs

Not everything is gun work. Tear-off repairs, flashing, edge metal and small patches all get hand-driven, and the range covers it: #11 x 3/4 in. for thin work, #11 x 1-1/4 in. as the general-purpose size, #11 x 1-3/4 in. and #11 x 2 in. for thicker assemblies, and #11 x 3 in. where a fastener has to reach through a build-up.

The 30 lb bulk boxes — the #11 x 1-1/4 in. and #11 x 1-1/2 in. electro-galvanized nails — are what a working crew buys for a full roof rather than the pound boxes.

Electro-galvanized is the standard coating here and is appropriate for inland Los Angeles work. Near the coast, salt air is hard on light coatings, and the corrosion logic is the same one that governs siding fasteners — see our siding materials comparison for how metallurgy and staining interact on an exterior.

Tile and metal: different fasteners entirely

Concrete and clay tile roofs are common across the older LA basin, and they need a fastener long enough to pass through the tile and any batten and still land properly in the sheathing. The #8 x 5-1/2 in. steel tile nail is the item for that, and the length is not negotiable down — a tile nail that stops in the batten is holding nothing when the tile lifts.

Metal roof and wall panels are screwed, not nailed, and the fastener is doing two jobs: clamping the panel and sealing its own hole. Washer-head hex screws in electro-galvanized zinc cover the range — the #9 x 1 in. and #9 x 1-1/2 in. sizes for panel-to-purlin work, the #12 x 2 in. and #12 x 3 in. sizes where the screw has to reach through insulation or thicker framing. Drive them perpendicular and stop when the washer compresses; a canted or over-torqued screw is a leak with a warranty argument attached. Point geometry and thread choice for sheet metal are covered in our self-drilling vs self-tapping screw guide.

Buying for an LA reroof

Count fasteners by square, not by intuition, and buy the pattern the manufacturer specifies rather than the one that gets the roof dried in fastest. Add a margin — running short on cap nails at four in the afternoon with underlayment down and no roof on it is how a job ends up exposed overnight.

Order the whole stack together. Underlayment caps, shingle coils, flashing nails and edge metal fasteners all get used on the same day, and they are cheap relative to the labour standing around waiting for them. Browse the full range in the roofing fasteners collection.

One last LA-specific note: if the property is in a Very High Fire Hazard Severity Zone, the roof assembly itself has requirements that go well beyond fasteners — our fire-hardening guide for LA property covers what Chapter 7A asks of a roof. And whatever the assembly, the edge details are where leaks start, so plan the fascia and edge metal at the same time as the field.

Frequently asked questions

What length roofing nail do I need for shingles?

Long enough to pass through the shingle and underlayment and fully penetrate the sheathing, or reach the minimum penetration the shingle manufacturer and your local code specify. On a typical single-layer job over standard sheathing that usually lands between 7/8 in. and 1-1/4 in., but a recover or a thicker deck pushes it longer. Check the assembly.

Do I have to use cap nails for underlayment?

For synthetic underlayment, effectively yes — the manufacturers specify capped fasteners and plain nails tear through. For felt the requirement varies, but caps hold far better on a deck that will sit exposed, which is worth it any time the roof will not be covered the same day.

Plastic caps or metal caps?

Plastic caps are the everyday choice and perform well. Metal caps hold up better to heat and UV on a deck left exposed for an extended period, and some assemblies and fire-rated details call for them specifically. Check what your underlayment and assembly require.

Can I use framing nails on a roof?

No. Roofing nails have a large flat head and a short shank sized to clamp a shingle without cutting it; framing nails have a small head that pulls straight through roofing material. They are not interchangeable — our framing nails guide covers what those are actually for.

What happens if the gun overdrives the nails?

The head cuts into or through the shingle mat, so the fastener no longer clamps and the hole is now a path for water. Back the pressure off, reset the depth, and hand-nail anything already overdriven. It is worth stopping the crew to fix.

Are electro-galvanized nails good enough near the coast?

Inland they are the standard and they work. In salt air a heavier coating or a more corrosion-resistant fastener is the safer specification, because coating failure on a roof shows up as staining and then as fastener loss years after the job is signed off.