In Part 1 of our shingle nailing series, we showed that skill, training, and craftsmanship are the most important part of quality roof work. Here in Part 2, we look at where to nail shingles and what nailing techniques to avoid, regardless of roof differences.
Where to Nail Asphalt Shingles
Material roof differences like cedar, slate and tar all require experts to install. It’s not just about the type of roof but the quality of the workmanship. Any shortcuts taken by the installers will cause problems. It takes skilled and experienced professionals to know exactly where and how to nail asphalt shingles. Nailing too high will cause shingles to lift and break in high winds. Nailing too low will create weak spots between the sheets. Both improper techniques can cause leaks even during light rain. Water damage leads to problems that worsen over time. There are two main nailing techniques that roofing professionals must master to do the job right. Four-Nail System: The four-nail system is common for homes with asphalt or architectural-style shingles.
- Drive a nail about ¾ of an inch from each end of the shingle.
- Find the tab breaks.
- Put a nail right on the tar line directly above each tab.
Six-Nail System: This is common for steep roofs and uses six nails per shingle.
- Drive a nail about ¾ of an inch from each end of the shingle
- Find the tab breaks.
- Put a nail directly on the tar line on both the left and right sides of the tabs.
These might seem simple, even basic, but they’re difficult to get right every time for the thousands of shingles and nails in one roof. The performance differences between two seemingly identical roofs can be huge just because of the nailing work. The shingles must be layered, aligned and nailed exactly right. The nails must be right on the tar lines for sealing and must also go through the shingle underneath.
Poor Shingle Nailing Techniques
It’s easy to think shingles will always be perfectly nailed into place because roofers use pneumatic nail guns. Nail guns are great time savers, but if the air pressure is too high or too low, a nail will be over-driven or under-driven. That’s why a skilled trade like roof construction requires expert knowledge of the tools and absolute precision.
- An over-driven nail sinks the nail head too low into the top shingle mat. This weakens the shingle and leaves it vulnerable to leaking in inclement weather.
- An under-driven nail doesn’t fully pierce the top and bottom layers, so individual shingles will lift and flap in the wind, or even be blown off.
- Nailing at the wrong angle will cause problems. It’s incredibly easy to get that angle wrong.
- Improperly located nails (too high or too low) can cause shingles to lift or break and let water in.
So much depends on the skill and care of the roofer. Of course roofing materials are important, but they won’t stop leaks if they are installed poorly. The only way to prevent water damage, wood rot, mold and expensive repairs is to nail every shingle properly. Despite roof differences, materials and architectural designs, only training, precision and years of experience will get the job done right every time.
Access other parts to this blog here:
As a renovator Doug did many rot repairs which gave him a good understanding of where and why buildings leak, and how to prevent it. He realized the need for a different approach to roofing; one that educated the customer enough to make good decisions. With better trained installers and a quality inspection process Absolute Roof Solutions was born…” Read more.
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