How Many Nails Per Shingle Does Code Require?

Four nails per shingle is the standard application for most laminate asphalt shingles, and the roofing chapter of the Oklahoma building code, OAC 748:20, does not set a count at all. Code specifies the fastener itself. Arrowhead Roofing installs six per shingle on every Tulsa roof, which is the enhanced pattern the manufacturer’s own instructions describe.

Note: this is a general guide only. Fastening requirements come from the current adopted code and from the installation instructions for the specific shingle on your roof. Your installer should verify both.

The count varies by shingle, because the shingle count per square varies. These figures are from the manufacturers’ published specifications.

The Short Answer

There are two separate requirements and they get confused constantly.

The code governs the fastener. IRC R905.2.5 requires a nail long enough to pass through the roof sheathing or to penetrate a minimum of three-quarters of an inch into it. The nails we run are 1-1/4 inch minimum, 3/8 inch minimum head diameter, 10 to 12 gauge. That specification meets the standard. It does not beat it, and we would rather say so than claim otherwise.

The manufacturer governs the count. R903.1 and R904.1 require a roof assembly to be installed in accordance with the code and the approved manufacturer’s instructions, which is what makes the instruction sheet a code document rather than a suggestion.

So the honest structure of our own claim is this: we meet the fastener standard, and we use fifty percent more of them.

What the Manufacturer’s Instructions Actually Say

GAF’s installation instructions for the Timberline LayerLock products, which includes HDZ and UHDZ, specify four nails per shingle for standard application. The same document describes the six-nail pattern as “required by some local codes and required for enhanced wind coverage on certain products.”

That wording matters in both directions. Six is not something we invented, it is the manufacturer’s own enhanced pattern. And GAF says enhanced wind coverage on certain products, so nobody should tell you that adding two nails upgrades the wind coverage on your particular roof. What applies to your roof is written in that product’s limited warranty.

The Arithmetic

Timberline HDZ and UHDZ both run 64 shingles per square, so the difference is easy to see on a real roof.

Nearly four thousand additional fasteners on an average Tulsa house. It costs us time and it costs us nails, and it does not appear as a line item on anyone’s estimate.

Why We Do It When Nobody Requires It

Andy Anderson at Arrowhead says it better than a marketing sentence would:

Not all roofs are six-nailed. We six-nail our roofs because it gives it a better wind rating. Even though the manufacturer doesn’t require me to six-nail, the state doesn’t require me to six-nail, we do it just because it’s a better install.

The voluntary part is the point. A standard met because an inspector will check it is compliance. A standard met when nobody is looking is a choice, and it is the same choice on every roof we build whether or not the job carries a top tier warranty.

What we will not tell you is that it makes a roof immune to wind. Better fastening improves uplift resistance. Nothing makes a roof wind proof, and a homeowner who reads otherwise and then loses shingles has a fair grievance.

Nails, Not Staples

Arrowhead only uses nails. Staples were common on older Tulsa roofs and they are still occasionally used, and they are the single most avoidable warranty problem we find.

A staple has two thin legs and a narrow crown instead of a broad flat head. It holds less, it is far more sensitive to being driven crooked, and manufacturers exclude damage caused by improper fastening. If a roof blows off and the fastener was wrong, that is a declined claim.

Improper fastening generally means one of three things: too few nails, nails placed outside the shingle’s nailing area, or staples where nails were specified.

What Changes the Requirement

Four nails is the common standard, not a universal one. Three things move the number, and the first is simply which shingle you are looking at.

The shingle on your roof

Pieces per square vary from 56 to 79 depending on the profile, so the same nails-per-shingle count produces very different nails-per-square totals. Heavier designer shingles sometimes specify five nails as standard rather than four.

The deck underneath

A fastener is only as good as what it goes into. Code requires the nail to pass through the sheathing or reach three-quarters of an inch into it, so deck thickness and fastener count are the same conversation. Thin, delaminated, or spaced decking undermines any nailing pattern.

High wind areas and local amendments

Some jurisdictions adopt amendments that require the six-nail pattern outright. That is exactly the case the manufacturer’s instructions are describing when they say “required by some local codes.”

Related Questions

Does insurance pay for the extra nails?

No, and it should not. A carrier pays what the code and the manufacturer require, and anything a contractor chooses to do above that minimum is the contractor’s own cost, as covered in does insurance have to pay for building code upgrades on a roof in Oklahoma?

How many nails will my whole roof take?

Multiply the nails per square by your roof’s square count, which is its area in hundreds of square feet. How many bundles of shingles are in a square? explains how that number is arrived at.

Can you tell how a roof was nailed without tearing it off?

Sometimes, from a lifted shingle at a rake or an exposed course, and always at the tear-off. It is one of the things we look at during an inspection, because a backed out or mislocated fastener shows up on the surface long before the shingle moves.

See Also

The two answers next to this one are what a carrier owes on code required work, which is where the manufacturer’s instructions become a coverage question, and how shingles are counted, ordered, and priced.