How a Shingle Repair Actually Works
Step 1: Break the Tar Seal
The first step is to break the tar seal on the shingle you’re trying to replace, and on the two shingles above that shingle. I use a pry bar / flat bar (sharpened from use) to do this, starting at the end of the shingle and working my way in.
Step 2: Remove the Nails
Next, remove the nails that are in the shingle you’re trying to replace from the row above that shingle. Each shingle is fastened with two rows of nails unless the roof is high-nailed. I jam the flat bar up to the nail, working below the shingle that it fastens, and pry it loose by pushing the flat bar down against the roof. After the nail is somewhat up from the decking, I go on top of the shingle and slap it down with the flat bar so the shingle is flush against the roof surface and the nail is sticking up. Then I pull the nail the rest of the way — most roofing nails are only 1¼” long so they don’t have far to go.
Repeat for every nail — the ones from the row above and the ones on the nail line of the shingle you’re removing. Should be 10–12 nails for architectural, maybe 8 for three-tab. The shingle should slide out freely. If it doesn’t: it’s shoulder-nailed (you can pinpoint the nail by rotating the shingle), it’s sticking to Ice & Water Shield, or you missed a nail.
Step 3: Slide the New Shingle In
Slide your new shingle into place, lining it up with the shingle to the left and the right. Put at least five nails through the nail line on the new shingle, and keep the nails 6” from the rain course above the shingle you’re fastening to prevent leaks.
Step 4: Replace the Nails You Removed
Replace the nails you took out from the row above. Put the new nails about 1” from the old holes — if you reuse the existing holes it won’t have the holding power or wind rating it’s supposed to. Many roofers skip this step.
Step 5: Seal Everything
Seal with Karnak (asphalt roof cement). Seal all the nail holes from the row above the shingle you replaced. Use a line of Karnak to replace the tar seal you broke — don’t get it too low or use too much or you’ll make a mess.
For architectural shingles: new on top of old doesn’t need the tar seal replaced with Karnak because you have a fresh tar strip. Old on top of new (above the repaired shingle) does need Karnak.
For three-tab shingles it’s the opposite: new on top of old does need a line of Karnak. Old on top of new doesn’t — the sun will seal it up as long as temperature is above 45°F.
Pro tip: you can harvest granules from the gutter and use them to camouflage any Karnak or sealant that’s visible — like on face nails for the last ridge cap shingle.
Step 6: Match the Shingle
I pull a sample and bring it to the supply yard to make sure I get the closest (or perfect) match. Shingles fade over time and the name on the wrapper doesn’t always tell you what you need.
Getting a close match matters more than most people realize. Ohio is a “reasonable matching” state for insurance purposes — if your shingles can’t be matched, it can actually help your claim down the line. But a bad color match from a sloppy repair can put you in a worse position. Sometimes a repair with Ice & Water Shield and Karnak makes more sense than forcing a shingle that doesn’t match.
Why You Shouldn’t Wait
When a shingle is missing, it’s exposed decking, underlayment, or worse — nothing between your home and the weather. Letting it go leads to cascading damage: water gets in, the decking rots, surrounding shingles loosen, and a repair that would’ve been a few hundred dollars turns into a few thousand. A good repair done right gives you peace of mind and protects the rest of your roof.
The most common causes I see are wind damage (Columbus gets enough straight-line wind events that missing shingles are practically seasonal), tree limbs, and critter damage — squirrels and raccoons can tear shingles up surprisingly fast.
What It Costs
A straightforward shingle repair — a few missing or damaged shingles — typically runs $250 to $500. Some repairs I’ll do for as little as $100 depending on what’s going on. I self-perform every job, so there’s no sales commission or crew overhead baked into the price.
If you feel like you can’t afford it, call me anyway — let’s figure it out.