Wondering if you have bad nailing in your roofing? Learn the differences between good nailing vs bad nailing practices and why they matter in roofing.
Sometimes your roof can look perfect from the outside, pass every visual inspection, and still fail to deliver over the years. You wonder if the shingles were cheap or the weather was too rough, but the real issue is often hidden in the installation itself, it’s bad nailing.
Proper fastening is the mechanical attachment that holds a roofing system together. It’s what keeps shingles anchored through wind, rain, and decades of heat movement.
When it’s done right, the roof can last for years. When it’s done wrong, even the best of shingles on the market can’t prevent sealing failures, blow-offs, raised tabs, and buckling, leading to a roof failure.
This article is all about what proper fastening in roofing looks like and the differences between good nailing and bad nailing practices.
Why Is Fastening So Important In Roofing Systems?
Proper fastening carries a lot of weight in roofing performance.
Various roofing materials, be it shingles, underlayment, starter strips, or ridge caps, rely on fasteners to stay in place. In most residential roofing, corrosion-resistant roofing nails do the job.
Nails ensure the roof stays in place, even in strong winds trying to peel it off. During heating and cooling cycles, materials expand and contract, and nails hold the materials firmly to the roof deck season after season.
But all of that only happens when the fastening is done properly. It means every nail is performing at its full holding strength.
That’s where good and bad nailing practices come in.
What Are Good Nailing Practices in Roofing?
Good nailing in roofing usually has 4 defining characteristics. These ensure the long-term performance you look for in a roofing system.
- Correct Nail Placement
Roofing components usually have a specific fastening zone or nail line. When the nails are driven through that, they secure the shingle they pass through. It also helps anchor the shingle below using an overlapping-layer system. So, the proper placement of nails is what makes the whole system work.
- Sufficient Penetration Depth
Proper nailing fully penetrates through the roofing material and anchors into the deck sheathing. This penetration depth ensures that the nail shank grips the structural deck and provides resistance against wind uplift and movement.
[Note: The exact depth depends on the material and deck thickness, but the principle of nails reaching and anchoring into the deck stays the same]
- Accurate Nail Alignment
A nail should be driven perpendicular to the roof surface. The nail head has to sit flat and flush against the shingle. This kind of even contact distributes the holding force correctly across the nail head. The flush seating also ensures the shingle lies flat for a perfect thermal seal.
- Right Number of Nails
How many nails are used in roofing also matters. Usually, roofing manufacturers specify the number of nails to use based on performance testing. The right number of nails helps distribute the load evenly across the roof surface, ensuring adequate holding power to resist rough weather.
What Are The Bad Nailing Practices?
The thing about bad nailing is that you don’t notice it until you see a leak or a blow-off. When you get close to inspect, you might see one of the following things
- Underdriven Nails
An underdriven nail is one whose head doesn’t sit properly and remains raised above the shingle surface. This prevents the overlapping shingle above from lying flat, which interferes with the self-sealing strip. It leads to poor sealing, allowing wind to lift the roofing material more easily.
- Overdriven Nails
An overdriven nail is one that has been driven too deeply into the shingle material. When that happens, the shingle loses its holding capacity because of tearing or fracturing around the nails. In this scenario, it looks like the nail is firmly holding the shingle, but in reality, it’s only damaging it further.
- Angled or Crooked Nails
If the nail is driven at an angle or it’s crooked, then it misses the whole point of securing the shingle material to the deck. It may either partially penetrate the deck or may completely miss it. Whichever it may be, the outcome is that the nails don’t have any holding strength to resist strong winds.
- Incorrect Nail Placement
As discussed above, roofing materials have a specific fastening zone. Any nail placed outside is considered a wrongly placed nail. The most common wrong placement for a nail is high nailing, where the nail is placed above the designated zone. This incorrect placement results in improper overlapping and poor interlayer bonding.
What is the impact of Bad Nailing on Roof Performance?
If your roof was installed with bad nailing practices, you will likely come across the following roof performance issues.
Wind Damage
Bad nailing fails to properly secure roofing materials, making them much more vulnerable to wind uplift. As a result, shingles loosen over time. So, when there’s a strong wind, the shingles will lift, curl, or suffer complete blow-offs.
Water Intrusion
Nails driven poorly can damage roofing materials or disrupt the proper alignment of shingles. This creates pathways for water to get inside your roofing system. Over time, this water intrusion leads to leaks, insulation issues, or deck rot.
Premature Roof Failure
Even with high-quality roofing materials, poor nailing can reduce the expected service life of the roof. With bad nailing, the roofing system can’t distribute stress across the entire surface, resulting in damage in specific areas over time.
How to Check for Bad Nailing?
Here’s the thing: bad nailing is almost impossible to notice, because from the outside, you can’t even tell if something’s off. You only find out about it when you see its impacts on your roof.
But actually checking your roof for bad nailing is quite simple. You can do it in two different ways –
Checking from the ground
The first one is to simply walk around your home and look at the roofline from various angles. If you see any of the following, then you have got bad nailing on your roof –
- Shingles with lifted tabs, curling edges, or a slightly raised middle.
- If the shingle courses seem shifted, offset, or misaligned.
- Missing shingles after a storm means they blew off.
[Note: While missing shingles doesn’t always mean a fastening issue, it should be the first thing to inspect.]
Checking from the Attic
To check the roof surface, you don’t have to get on top of the roof. You can check it from the attic.
When checking the attic for bad nailing, look for dark patches, soft spots, or discoloration, which often indicate decking saturation. Most of the time, the water staining will leave a trail to the nailing point if you have bad nailing.
When to Call a Professional?
Bad nailing issues like underdriven nails, overdriven nails, or high nailing can’t be spotted from the ground or the attic. That’s where you have to call for professional roof inspection services. They will visit your house and inspect the roof for any issues with nailing.
Why Follow Proper Installation Practices?
Now, if you fail to check for bad nailing before something happens, you have to go for roof repairs. These can be expensive, depending on the extent of damage your roof has suffered.
But with proper installation practices, you can eliminate that need. That’s why it’s crucial to hire experienced roofing contractors. Because they –
- Follow manufacturer recommendations and industry guidelines for proper fastening methods. Have professional training to understand correct techniques and avoid installation errors.
- Maintain high installation standards to ensure roofing systems perform effectively for years.
Working with a quality roof installation service can save you a lot of money from roof repairs and, most importantly, the struggle of dealing with roof issues.
Conclusion
At the end of the day, good nailing won’t make any noise, but neither will bad nailing. But the outcomes are totally different.
While good nailing keeps your roof anchored through everything, bad nailing works against your roof the whole time. Good nailing will silently save you money, while bad nailing is going to cost you a lot at some point.
So, instead of waiting around for something to happen, request your free roof inspection with us to get those bad nailing practices fixed.