When it comes to roofing, nailing shingles properly is crucial for a sturdy and watertight roof. But what about the tar line? Do you nail shingles on the tar line, or is there a different method? Let’s dive into this common roofing question and clarify the best practices.

Understanding the Tar Line

Before we discuss nailing shingles on the tar line, let’s clarify what the tar line is. The tar line refers to the adhesive strip on the back of asphalt shingles. This strip contains a layer of asphalt that, when exposed to heat from the sun, becomes tacky and helps bond the shingles together, creating a waterproof barrier.

Nailing Above the Tar Line

When it comes to nailing asphalt shingles, the general practice is to nail above the tar line. Roofers typically place nails about 6 to 8 inches above the lower edge of the shingle, ensuring they secure the shingle to the roof deck or sheathing. This placement provides several advantages:

  1. Prevents Leaks: Nailing above the tar line helps prevent water from seeping into the holes created by the nails. This is crucial for maintaining a watertight roof.
  2. Enhances Wind Resistance: Placing nails higher up on the shingle provides better wind resistance. It ensures that the shingles remain securely attached, even during strong winds.
  3. Minimizes Cracking: Nailing below the tar line can increase the risk of shingle cracking due to expansion and contraction as temperatures change. Nailing above the tar line reduces this risk.

Examples of Proper Nailing

Here are a few examples of how roofers correctly nail shingles:

1. Three-Tab Shingles

For three-tab asphalt shingles, roofers often use four nails per shingle. These nails are placed in a specific pattern, with two nails near the top of the shingle and two more above the tar line but below the shingle’s adhesive strip. This pattern ensures secure attachment while preventing leaks.

2. Architectural Shingles

Architectural shingles are thicker and heavier than three-tab shingles. Roofers may use six nails per shingle to provide extra stability. As with three-tab shingles, these nails are positioned above the tar line to maintain the shingle’s waterproofing.


In the world of roofing, nailing shingles above the tar line is the tried-and-true method for achieving a dependable and watertight roof. Proper nailing ensures your shingles remain securely fastened, resistant to wind and weather, and free from leaks.


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

Write A Comment