Should Roofing Nails Be Exposed In Attic?

Should Roofing Nails Be Exposed In Attic

Should Roofing Nails Be Exposed In Attic? Roofing nails being visible in the attic is a common occurrence and is generally not a cause for concern from a structural standpoint. 

The nails that secure asphalt shingles to the plywood or OSB roof sheathing typically penetrate the attic 1/4 inch or more. 

Key Takeaways on Exposed Roofing Nails in the Attic:

  • Some nail exposure is normal, but extensive exposure could indicate problems with the roof installation.
  • Acceptable nail length is debatable, but protruding more than 1/4-1/2 inch may be problematic.
  • Exposed nails can leak, catch debris, rust, and compromise decking. But they may also pose little risk.
  • Causes include nails that are too long, missed rafters, inadequate installation pressure, and shrinkage.
  • Evaluate the location, degree of exposure, and roof performance. Selective sealing may be an option.
  • The safest bet is to have a professional roofer inspect and address any concerns with exposed nails.

Why Nail Exposure Occurs in the Attic

Before evaluating if exposed nails in the attic are an issue, it helps to understand some reasons they may be visible in the first place:

  • Nails too long – If excessively long nails are used, they can protrude through the roof deck into the attic space when installed.
  • Missed rafters – If nails miss the rafters and penetrate only the decking between rafters, this provides less holding strength, and they can pop up.
  • Poor installation – Inadequate pressure on the nail gun can result in nails not being fully driven and exposed on the underside.
  • Decking shrinkage – Over time, roof deck boards can shrink or warp, exposing nail heads that were originally flush.
  • Asphalt shrinkage – Shingles gradually shrinking as the roof ages may raise nail heads over time.

So some nail show through is inevitable and does not necessarily mean the roof is improperly installed or unsafe. But, extensive exposure could be a red flag of underlying issues.

Is it Normal for Roofing Nails to be Visible in the Attic?

There seems to be debate around whether exposed roofing nails in the attic space are normal and acceptable or a sign of problems:

Limited exposure expected 

Many sources state that some nails showing through in the attic are common and not a definite cause for concern. Over time, minor visibility of nails along occasional rafter lines is normal.

Extensive exposure problematic 

Roofing experts agree that seeing large numbers of nails protruding severely from the decking usually indicates installation issues, inadequate nailing, or deterioration that should be addressed.

1/4 inch rule?

Some roofers advise that exposed nails should not protrude more than 1/4 inch before becoming problematic. Others allow up to 1/2 inch if it occurs over time. But there is no definitive standard.

Location matters 

Nails along the rafters are less concerning than those between rafters without support underneath. Bunched areas of nails indicate issues.

So, while some nail visibility is expected, seeing large numbers of significantly exposed nails likely warrants closer inspection and repairs as needed.

Potential Risks of Exposed Nails in the Roof

Although limited nail show through may be considered normal, exposed nails do have some potential downsides:

  • Leaks – Exposed nails can create holes for water intrusion, especially if decking warps. Water stains, mildew, and damp insulation can result.
  • Rusting – Nails exposed to attic moisture have an increased risk of rusting and corrosion over time, weakening the fastening.
  • Pests/debris – Visible nails allow insects, wildlife, and debris to enter from the attic into a roof assembly. This can lead to clogged rafter bays and even damaged shingles.
  • Reduced wind resistance – Too many exposed nails could compromise the roof’s wind uplift resistance.
  • Damaged decking – Constant roof movement around protruding nails can eventually degrade the integrity of the roof decking.

The severity of these risks depends on the amount of nail exposure and roof age. Chances are minor if just a few nails are slightly visible along the rafters, and the roof is newer and undamaged. But, excessive exposure escalates the potential for problems.

Acceptable Length of Exposed Roofing Nails?

When it comes to exposed roofing nails, how much protrusion is too much? Recommendations vary:

  • Up to 1/4 inch exposure – Considered acceptable by some roofers if along rafter lines only. No action is needed.
  • Up to 1/2 inch – The maximum exposure that may be safe for older roofs if the deck remains intact. Monitor.
  • Over 1/2 inch – Potentially problematic amount of exposure, depending on location. Inspection recommended.
  • Over 1 inch – Excessive exposure from missed rafters or poor installation. Repairs are likely needed.

There is no definitive standard for safe nail length exposure. The consensus is limited visibility along rafters is expected, but protruding more than 1/2 inch or with extensive bunched areas could indicate issues needing assessment.

What To Do About Exposed Nails in the Attic

What should you do if you find exposed roofing nails in your attic? Here are some tips:

  • Inspect condition – Check if nails align with the rafters or are missing. Also, check for leaks, damage, or deterioration around exposed nails.
  • Measure exposure – Determine if nails exceed 1/4 to 1/2 inch protrusion depending on roof age. More than that could be problematic.
  • Assess risk – Consider roof age, extent of exposure, alignment with rafters, and signs of leakage. This can help gauge the severity.
  • Monitor and seal – Sealing nails may prevent moisture entry for limited exposure along rafters under 1/2 inch. Continue monitoring condition.
  • Professional evaluation – For excessive nail exposure or leakage, consult a roofer to inspect and recommend any needed repairs.
  • Reshingle roof – A full roof replacement may be required if nails were improperly installed and leak excessively.

For minor exposure, vigilant monitoring and sealing nails may suffice. But, the safest approach is to get a professional assessment to determine if repairs are needed. This provides peace of mind.

Roofing Nails In Attic

What Causes Excessive Roofing Nail Exposure?

Why might roofing nails be protruding excessively in the attic? Here are some potential causes:

  1. Incorrect fastener length – Nails that are too long can fully penetrate decking, creating visible protrusions inside the attic. 1-1/4″ to 1-3/4” nails are typically used.
  2. Missed rafters – Nails applied between rafters instead of into them have less holding power and are more likely to pop up from deck movement.
  3. Insufficient fastener spacing – Too few fasteners or improper spacing can lead to inadequate rafter connections and nail disengagement over time.
  4. Low installation pressure – Weak or improperly calibrated nail guns may not fully seat nails, exposing them. A minimum 120 PSI pressure is key.
  5. Decking shrinkage – Over many years, roof decking can shrink or warp, raising nail heads that were once flush. This may be unavoidable over time.
  6. Improper handling – Dragging bundles over rough surfaces or excessive walking on shingles can displace nails before they are sealed.

Preventing Exposed Nails During Roof Installation

The best way to avoid exposed nails in the attic is proper installation:

  • Use recommended fasteners – Roofing nails 1-1/4” to 1-3/4” long are suitable for most applications. Avoid excessively long nails.
  • Hit rafters – Aim for rafter locations, not just the decking between rafters, for maximum holding strength.
  • Check pressure settings – Set pneumatic pressure high enough (100-120 PSI) to fully seat nails.
  • Space nails correctly – Follow manufacturer specs for the number and spacing of nails per shingle. Don’t skimp.
  • Handle with care – Carry materials carefully and minimize foot traffic to prevent displacing nails before sealing.
  • Allow to seal – Let shingle adhesive fully seal nails before exposing the roof. It usually takes 24-72 hours in warm weather.

Proper training and workmanship go a long way in preventing exposed nails down the road. Retain proof of installation to protect warranty coverage.

Options for Addressing Exposed Nails in Existing Roofs

For older roofs with excessive nail protrusion, here are some repair options to consider:

  • Sealing exposed fasteners – Caulking or roof cement can temporarily plug holes and moisture entry points at minimal cost.
  • Spot replacement – Removing and replacing only damaged or degraded decking sections may suffice if leakage is limited.
  • Full roof overlay – Installing a new roof over the old one provides fresh waterproofing if the existing decking remains sound.
  • Partial re-cover – Overlaying the roof except for damaged portions is an alternative if the decking needs replacement in spots.
  • Complete tear-off – Fully removing old roofing and decking allows inspection and replacement of deteriorated materials for long-term remedy.

The best solution will depend on the roof’s age, the extent of damage, and your budget. Seek professional guidance to explore the right options for your situation.

Exposed Roofing Nails in the Attic

Some limited nail exposure in attics is expected over time, but significantly protruding, bunched, or excessive nails likely indicate an underlying issue needing assessment. 

While not necessarily an immediate threat, exposed nails present the potential for leaks, damage, and other problems long-term.

Your safest bet is to have a professional roofer inspect for proper nailing, provide repair recommendations, and address deficiencies. 

This preserves roof performance, prevents leaks, and protects your most important asset – your home. With the proper repairs and vigilance, exposed roofing nails don’t have to spell trouble.

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