Repair

Shingle Roof Repair: Nail Pops, Blisters and Cracked Shingles

By Maple Grove Roof Repair · October 25, 2026 · 8 min read

It's the last week of October, the roof is about to disappear under snow until April, and you've noticed something from the ground: a few shingles with a bump in the middle, a bubbled surface, or a crack across a tab. Is it a problem? Sometimes. Most shingle roof repair in Maple Grove this time of year comes down to these three: nail pops, blisters and cracked shingles. Here's how to sort them into cosmetic, fix-before-winter, and roof-is-done, with what each typically costs.

Nail pops

What it is. A roofing nail backing out of the decking and pushing up the shingle above it, so you see a small round bump, or the nail head itself once it's worn through.

Why it happens here. Freeze-thaw. The decking swells and shrinks with moisture through a Minnesota winter, and a nail that was driven at an angle, into a gap between sheets, or with a nail gun set too shallow, walks out a little every cycle. Warm attics with frost on the nails make it worse, because the nails rust and lose grip. Fast installs during building booms and decks that were wet at install are the usual background.

Minor or major? A handful of nail pops on a roof under 15 years old: minor, but fix them now. Each one is a hole waiting for the shingle above to tear, and a raised shingle is where ice dam meltwater and wind get in. Dozens across a slope on a roof past 20: the deck or the install is the problem, and it's a replacement conversation.

The repair. Pull the nail, drive a new one an inch away, seal both spots, re-seal the shingle. Typically $150–$400 for a visit that handles a dozen or so. A roofer who wants to hammer the pops back down through the shingle and dab cement on top is doing a one-winter fix.

Blisters

What it is. Raised bubbles on the shingle surface, from pea to quarter size. Closed blisters still have granules over them; open ones have popped and show bare asphalt.

Why it happens. Moisture or gas trapped inside the shingle expands in heat. The usual causes are a hot, under-vented attic baking the roof from below, a deck that had moisture in it at install, or a manufacturing defect. Blisters show up in the first few summers, and a roof that's blistering across a whole slope by year three has a ventilation problem or a product problem.

Minor or major? Closed blisters with granules intact: cosmetic, watch them. Open blisters: each is a spot where UV is eating the asphalt, and on a south slope they crack through in a few years. A few open ones on an older roof are a shingle-by-shingle repair; widespread open blistering is a slope that's near the end. Don't confuse blisters with hail. Hail bruises are soft dents with the mat crushed; blisters are raised and often have a crater. An adjuster knows the difference.

The repair. Individual blistered shingles replaced at $300–$800 for a small area. If the cause is the attic, fixing the ventilation with soffit baffles and a ridge vent, $500–$1,500, is what stops it. Our guide on attic insulation and roof health covers that side.

Cracked shingles

What it is. Cracks across the tab, either straight lines or a branching, crazed pattern.

Why it happens. Thermal cycling, mostly. A shingle here goes from deep winter cold to a very hot summer surface within the same year, every year, and the asphalt loses flexibility as it ages. Cracked shingles also come from foot traffic on a cold day, from a hail impact that fractured the mat, or from wind creasing on a shingle that lay back down.

Minor or major? This is the one that's rarely minor. A few cracked shingles on a roof under 15 years old, in one spot: a repair, $300–$800, and worth doing before snow sits on them for four months. Crazing across a slope on a roof past 20, especially with granule loss: the shingles are brittle and the roof is done. New shingles patched into a brittle field don't seal, and you'll be replacing the roof anyway.

Wind-creased shingles are their own category. A horizontal crease across a tab means the mat is broken even though it looks flat. It will lift and tear in the next straight-line wind, and if a storm did it, it may be a claim. The hail and storm damage page covers that.

Shingle roof repair in Maple Grove: the triage table

A ground-level check, step by step

You don't need a ladder to sort most of this out. Pick a bright afternoon with low sun, which throws shadows across raised spots.

1. Walk all four sides of the house with binoculars and a phone camera.
2. Look along each course for bumps in a straight line. That's usually a row of nail pops.
3. Check the south and west slopes for bubbles or bare black spots. Those are blisters, closed or open.
4. Scan the tabs near the ridge and the rakes for cracks, creases or corners that don't lie flat.
5. Look in the gutters and at the downspout outlets for granules or shingle pieces.
6. Open the attic hatch and check for rusty nail tips or dark spots on the deck under the area you photographed.

Note the roof's age and which slope each photo shows. That's what a contractor needs to tell you which row of the triage table you're in.

Why late October matters

Two reasons. New shingles need a few days above about 40°F to seal, and by early November that's usually over until spring, so anything on this list that needs new shingles should be done in the next couple of weeks. And once the roof is under snow, every one of these becomes a channel for ice dam meltwater sitting above your ceiling for months. A $300 repair now is the same repair plus a drywall patch in March.

Before you type "shingle roof repair near me" and call the first name that comes up, take binocular photos of what you've seen from every side of the house. Those photos let a contractor tell you on the phone whether it's a visit now or a note for spring. Our roof repair page covers what happens next, and a roof inspection will tell you which column of the table you're in. If the answer is the right-hand column on a 25-year-old roof, the guide on signs a roof is near the end and the cost page have the rest.

Common questions

Are nail pops a serious problem?

A few are a small repair, but they shouldn't be left through a winter. A popped nail lifts the shingle above it, and that gap lets in wind-driven rain and ice dam meltwater. Dozens of them across a roof usually point to a deck or installation problem rather than a few loose nails.

Can you replace just a few shingles?

Yes, on a roof that's still flexible. A roofer lifts the shingles above, pulls the damaged ones, and slides new ones in and nails them. On an old, brittle roof the surrounding shingles crack when they're lifted, and the new ones won't seal well, which is why a small repair on a 25-year-old roof is often a short-term fix.

What is Class A roofing material?

Class A is the highest fire-resistance rating for roof coverings. Most fiberglass asphalt shingles carry it, as do many metal, slate and clay tile roofs. It's a different thing from a Class 4 rating, which measures impact resistance against hail, so check both on the wrapper if you're replacing shingles.

Will new shingles match the old ones?

Rarely perfectly. Even the same product line fades and weathers over the years, so a patch can look a shade off from the street. On a back slope that rarely matters. On the front of the house, ask the contractor to bring a sample shingle before ordering.