Roofing is a specialized skill that must meet specific building codes. One question that you might have about putting on a new roof is the spacing of the nails. How far apart should rooting nails be placed? We have researched and found the answer to that question and a few more.
Nail placement is key to the performance of the shingles. When installing shingles, one must follow the manufacturer's installation instructions that specify the proper placement of roofing nails to guarantee the warranty and meet the International Building Codes. There are two basic nail patterns used in roofing:
- Standard nail pattern
- High wind or steep slope pattern
If you still have some questions about roofing nails, don't worry. In this post, we'll discuss the topic in more detail. Please keep reading to find out more information about roofing nail patterns, types of roofing nails, and other common questions that people ask about them. Without further ado, let's get into it.
Consistent shingle pattern layout throughout the roof and an even and uniform nailing pattern distribute the stress evenly across the roof, creating a solid structure that can withstand the forces of nature's elements.
Shingles must be laid out in the proper installation pattern with the overlaps in the right places. Besides a seamless, attractive look, the appropriate overlap is essential to controlling water flow. Otherwise, water can't shed correctly and will get to where it shouldn't be, leading to leaks and expensive water damage.
Proper installation should be done manually by hammer or with a pneumatic gun that is properly adjusted. If the nails over penetrate or under penetrate into the shingle, the performance is compromised, leading to raised shingle tabs, nail corrosion, buckling, shingle blowoff, and sealing failures.
How many nails per shingle?
IBC code calls for manufacturer minimum standard, which is generally four per shingle but never less than four nails per strip shingle or two per individual shingle.
However, that can vary by nail pattern based on region and local building ordinances, so make sure you use a highly reputable and licensed roofer well versed in all required building codes.
Standard Nail Pattern
The standard nail pattern on a three-tab shingle calls for four nails per shingle at 6 1/8 inches above the butt edge. There should be two placed 1 inch inward from each edge. The other two nails go 12-13 inches inward. The nails should be placed 1/2 of an inch above the cutouts but below the sealant strip.
High Wind or Steep Slope Pattern
In high wind areas or coastal areas, the nail pattern increases to five or six nails per shingle to enhance the holding power and security of the shingles.
If a roof slope exceeds 21 units vertical to 12 units horizontal, then manufacturer installation instruction will specify additional nails, probably increasing to six.
With an increased number of nails, none should be within 2 inches of a joint. Each shingle should also be sealed with asphalt plastic cement evenly spaced 2 inches above the bottom edge.
However, it is noteworthy that the number of nails per shingle doesn't matter much if improperly located. More nails in the wrong place can do more harm than good.
If shingles are nailed too high, it allows wind to get up under the shingle, eventually loosening it. It can also increase the nail head's exposure to water which causes problems over time.
Take a look at this tutorial:
What size are roofing nails?
Roofing nail measurements refer to diameter and length. There is a head diameter and shank diameter to consider.
International Building Code (IBC) specifies that the head of roofing nails must be a minimum size of 3/8 of an inch or 9.5 millimeters for compliance.
IBC codes require that roofing nails be a minimum of 12 gauge or 2.67 millimeters. The smaller the gauge number, the larger the nail, so you will also see roofers use 10-gauge and 11-gauge nails.
The IBC doesn't state a specified length for roofing nails. However, it does specify that nails must penetrate through the roofing material and must not be less than 3/4 of an inch (or 19.1 mm) into the sheathing. In cases where the sheathing is less than 3/4 of an inch, the nails must penetrate through the sheathing.
Roofing nails come in sizes that vary between 1 and 2 inches in length to give roofers flexibility to make adjustments to accommodate roofing shingle and underlayment thickness variants and still meet code.
To calculate the correct nail length, add the thickness of the shingle and the underlayment. Then calculate the thickness of the sheathing to make sure that the nail has enough length to penetrate the sheathing enough to meet building codes.
Are there different types of roofing nails?
Roofing nails are common for different jobs within the roofing process, and your roofer needs to know the appropriate time to use each kind. Other roofing jobs may use different types and materials of roofing nails and fasteners.
While shingle installation probably comes to mind first and gets the most attention, roofing felt and flashing also use roofing nails.
Roofing felt is a waterproof material made from polyester or glass fibers that is used underneath the shingles and is generally tacked using regular roofing nails for convenience. However, an expensive nail is not required, and staples are also acceptable.
The IBC states that fasteners for asphalt shingles must be stainless steel, galvanized steel, aluminum, or copper roofing nails with a minimum 12-gauge shank and a minimum 3/8-inch diameter head.
However, roofing nails will always have a distinct diamond-shaped point regardless of the material. This feature is crucial because it allows the nail to penetrate through the decking while leaving it intact.
Steel nails may be galvanized or stainless steel. Steel is strong and resists rust and corrosion very well.
Galvanization adds a layer of zinc to the nails to help with rust and corrosion. The hot-drip method forms a thicker zinc layering than the electro-galvanized one. Galvanized is the best type of nail and is most commonly used with asphalt shingles.
Stainless steel nails
Stainless steel nails are strong and best used on hard surfaces like ceramic or slate roofing. They may also be used on asphalt shingles in a coastal region when keeping to a tight budget.
Copper is a strong material and has a natural resistance to rust and corrosion. However, it is more expensive, so it is not used often except on copper roofs or those with copper accents.
Regardless of cost, it's the best nail choice for slate because its properties allow endurance that matches the slate roof's longevity, which can be up to 100 years.
Aluminum nails are the weakest of the roofing nail materials and are more prone to corrosion and damage from salt and chemicals. Despite their weakness, these nails are frequently used because they are inexpensive and meet the minimum IBC standard.
The long part of the nail with the puncturing tip is the shank. There are three basic shank types found on roofing nails.
The most common type used is the smooth shank nail. As the name states, it is long with no ridges or texture. Its lack of complexity makes it inexpensive to manufacture and easy to drive into surfaces.
While it is the most common, it is not the most effective. The smooth shank lessens the withdrawal resistance and overall holding power.
The ring shank nail has rings along the shank. These rings are separated and different than continuous rings like those found on a screw. The rings allow the nail shaft to bite into the roofing material, providing a better grip than a regular shank nail. These types of nails are also called corrugated nails or annular nails.
The screw shank nail has a body like a screw with its continuous spiraling ring along the shank. This nail type has the most holding power, but it's not often used because it's expensive and challenging to drive into hard woods.
While screw shank nails are similar to regular screws, they are not interchangeable. Screws are not approved for roofing and should never be used because they leave a gap that can cause leaks.
Do you need to seal roofing nails?
Shingles should cover roofing nails. Therefore, you should not have exposed roofing nails on the shingles. If you find exposed nails in a new roofing job, you probably need to contact your roofer. If not redone or sealed, you have the potential for a future leak.
There are a few products that you can use to seal exposed nails. Roofing tar is popular and very effective. It is an inexpensive waterproof product that can expand and contract with the roof through temperature fluctuations.
Silicone and polyurethane sealants are also commonly used, especially by the roofing and construction industry. They are more expensive but have some advantages, such as being transparent with a fast curing time.
Read more: How To Seal Roofing Nails
How far apart are the nails on the drip edge?
Shingle manufacturers recommend installing a drip edge on top of the underlayment at all rakes and below it at the eaves. Drip edge installation follows a nail pattern that differs from the other shingles.
Attach the drip edge to the roof deck, placing the nails 8-10 inches on-center and 1 1/2 inches to 3 inches from the sheathing edge. There should be a minimum 2-inch overlap with the next piece of drip edge.
Asphalt shingles should cover the drip edge with an overhang of 1/4 of an inch to 3/4 of an inch on the exterior side.
To Sum it Up
Roofing nails hold your shingles in place, so your roofer must understand proper nailing patterns and adhere to all manufacturer's installation instructions and building codes to ensure that your roof protects your home from leaks.