Nails are the primary fasteners used to hold your asphalt shingle roof in place. There are issues with nails that can affect your roof. You can prevent severe damage by knowing how to recognize these issues.
Over-driven nails are those that are driven so deeply into the shingle that it buckles. The nail presses the shingle inward at the nail location, causing the shingle on either side to lift up. The shingle will begin to crack at the nail location and water can seep under the lifted edges. Over-driving is often a result of a DIY repair attempt. The nail will damage the shingle, necessitating replacement.
The opposite issue is under-driving. This is most often caused when a nail gun is set incorrectly so it doesn't drive in the nail as deep as necessary. The nail head ends up slightly elevated above the shingle. On a windy day, the shingle will lift along the nail shaft and become hung up on the nail head. This results in lifted shingles that allow water underneath. If caught early, the nails can be driven in to the correct depth before shingle damage occurs.
3. Insufficient Number
An insufficient number of nails can lead to shingle failure, particularly in a storm. Most asphalt shingle systems, for example, require four nails at a minimum but six may be recommended in areas prone to high winds. The issue often isn't spotted until after a storm rips off a few shingles. If this occurs, a roofer must replace the damaged section and then re-nail the remaining shingles with the appropriate number of nails.
4. Weather Popping
Weather popping is a phenomenon that occurs when temperature fluctuations cause the nails to pop out of the wood roof decking. It's caused by the swelling and shrinking of the wood fibers around the nail shaft during rapid temperature changes, so it is more common in areas that swing between freezing and warm temperatures. Prevention is difficult, although longer nails are sometimes used in areas prone to weather popping. Frequent inspections may be necessary so popped nails can be repaired as soon as they occur.
5. Nail Tears
If a shingle comes loose due to any of the above reasons, the risk of a nail tear develops. Shingles may also tear if they are nailed in the wrong location, such as too near the edge, which also tends to be a DIY roofing mistake that is avoided by hiring a roofing service. Repairing loose shingles promptly prevents nail tears. Once a tear occurs, the shingle must be replaced.
Contact a roofing service like Select Exteriors if you need to repair or replace a damaged roof due to nail issues.