Knowing how to properly nail asphalt shingles is crucial in ensuring that your roof’s shingles remain in place and perform optimally over time.
Unfortunately, improperly placing and overdriving nails are among the most common mistakes DIY’ers and even some more experienced roofers may make when nailing asphalt shingles. However, you can take some simple steps to avoid these issues and help your roof withstand the test of time.
How Do You Select Proper Roofing Nails for Asphalt Shingles?
First, read the manufacturer’s instructions regarding the proper nails for your asphalt shingles and the recommended number of nails per shingle. (Tip: Purchase more nails than recommended to account for any mistakes where you’ll need to replace an improperly positioned nail.)
As a rule, your roofing nails should be corrosion-resistant and made of stainless steel, galvanized steel, or aluminum. Roofing nails should have a minimum shank diameter of 12 gauge, and the nail heads should have a diameter of >3/8ths”.
The nails also need to be long enough to penetrate a minimum of 3/4” into the roof deck. If the deck’s thickness is < 3/4”, the roof nails should be long enough to penetrate and extend through the deck by > 1/8th”. When determining appropriate nail length, you’ll need to account for the thickness and number of shingle layers, underlying wood decking (see below), and the thin metal flashings used to direct water away from particular areas (e.g., chimneys).
Evaluate the Condition of Your Roof Decking
When considering the proper roofing nails, don’t forget the importance of evaluating the plywood or other wood beneath your shingles. The roof’s framing holds up the decking, but it’s the decking that essentially serves as the roof.
Rotting plywood due to moisture is unable to support a roof’s weight when compared with healthy wood. It also cannot appropriately grip the roofing nails. Further, because rotten roof decking absorbs moisture more readily than healthy wood, the roof shingles will probably begin to allow in moisture, and water will ultimately leak into the attic.
If you’re using a roofing contractor, ensure your contractor thoro
ughly inspects the condition of your decking from the inside of your attic if it is accessible. Your contractor should replace any decking sections that show damage. Otherwise, if you place new shingles onto a damaged or rotting roof deck, your shingles will easily become damaged, causing water pooling in sagging areas and leaks.
The roof may also begin to shift, resulting in more leaks. Further, the roof nails will not hold, which in turn can result in the loss of large sections of shingles secondary to gravity or wind.
How to Nail Asphalt Shingles: Properly Positioning and Driving Roofing Nails
The manufacturer of your asphalt shingles will provide you with specific instructions on how to nail shingles, including appropriately placing and driving your roofing nails. Unfortunately, some roofers don’t follow these instructions, resulting in misplaced and overdriven nails. (See below for more information.) You’ll also need to follow local building code regulations.
In addition, follow these tips:
- Align your shingles appropriately before nailing.
- Position the roofing nails per the shingle manufacturer’s specifications.
- Keep the nail straight at 90 degrees to prevent the nail’s head from breaking the shingle’s surface.
- Drive the nail straight and flat so that it’s flush with the shingle surface. Otherwise, you’ll risk underdriving or overdriving the nail.
- Immediately correct improperly positioned or driven nails.
- Never drive nails into cracks or knot-holes in the roof deck.
- Always nail the shingles going from one side to the other to keep your shingles flat.
- Particularly if using a nail gun, take extra care to ensure accuracy.
- Never use staples to fasten your roof shingles.
Preventing Improper Driving and Placement of Roofing Nails
When a nail is overdriven, its head goes right through the shingle’s mat. Using nail guns increases the likelihood of overdriving nails. For example, if you’re using a pneumatic nail gun and have set the pressure too high, that pressure will drive the roof nails directly through the shingle. Rather, roof nails should be flat and flush with the tile and properly penetrate into or through the deck, as discussed above.
Overdriven nails reduce the shingles’ resistance to wind, increasing their risk of loosening and blowing right off the roof. Overdriven nails will also void your manufacturer’s warranty, meaning you’ll be responsible for the cost of purchasing new and placing new shingles.
Nails that are correctly placed capture and secure the top edge of the shingle that lies underneath. Yet if you’ve placed your nails too high up, it won’t capture and secure the shingle below. Further, improperly secured shingles are less wind resistant, tend to slide right out of the nail holes, and can blow off the roof. Improper placement of tiles also voids the manufacturer’s warranty. In some cases, improper tile placement may necessitate retiling the entire roof.
If you follow the manufacturer’s instructions, local building codes, and the simple guidelines above, you’ll be able to avoid common pitfalls and properly nail asphalt shingles to your roof. Everyone in your neighborhood will agree that “you’ve nailed it!”