Roof Shingles: 7 Critical Mistakes Roofing Contractors Make (And How to Avoid Them)

Why Proper Installation of Roof Shingles Matters

Getting roof shingles installed the right way is just as important as choosing the right material. Even the best shingle roofing won’t last if it’s not put on properly. Roofs often fail too soon because they weren't installed properly, according to experts in the field. When mistakes happen, they can lead to:

• Leaks and Water Damage – Gaps or misaligned shingles allow water to seep in, causing rot and mold.
• Higher Energy Bills – Poor insulation leads to heat loss in winter and extra cooling costs in summer.
• Shorter Roof Lifespan – A roof that should last decades may need repairs or replacement much sooner.
• Voided Manufacturer Warranties – Many roofing companies won’t cover issues caused by improper installation.

Getting a shingle roof isn’t just another home project—it’s something you want to last for years. But if the job isn’t done right from the start, you could end up paying for repairs later on. That’s why it’s so important to hire experienced pros and make sure the right steps are followed.

In this post, we’ll look at the 7 most common mistakes roofing contractors near me often make when putting in asphalt shingles—and what you can do to avoid them.

7 Common Mistakes Roofing Contractors Make When Installing Roof Shingles

1. Putting Nails in the Wrong Spot

Believe it or not, nails are one of the most critical things to use while putting on roof shingles. If you put them in the wrong spot, it can cause huge problems down the road. If the weather is bad, you can witness shingles coming loose or even flying off your roof.

Here are some mistakes people often make:

• Not using enough nails per shingle: If there aren’t enough nails, shingles can easily shift or fall off.
• Nailing too high up on the shingle: Nails placed too high won't hold the shingles securely, especially when winds pick up.
• Hammering nails too hard: This pushes the nail straight through the shingle, creating holes and leaks.

How to Do It Right:

Always check the instructions that come with your asphalt shingles. Usually, manufacturers suggest using four to six nails per shingle, placed right in the marked area (called the nailing strip). It's also smart to use nails that won't rust, since rusted nails might cause difficulties sooner than you think.

2. Misaligned Roof Shingles

When shingle roofing isn’t lined up properly, it can leave gaps that let in wind and moisture. Over time, this can lead to leaks, damage, and costly repairs. Some common mistakes include:

• Crooked rows – If roof shingles aren’t lined up straight, they won’t just look off—they also won’t cover your roof the way they should.
• Incorrect overlap – If shingles aren’t layered correctly, they won’t keep water out the way they should.
• Too tight of a fit – When the weather changes, asphalt shingles need a little room to grow and shrink. They can bend or warp if they are packed too tightly.

How to Get It Right:
Roofers often snap chalk lines to make sure shingle roofs are straight and evenly spaced. When the shingles line up right, the roof looks better—and more importantly, it helps water drain off properly, which lowers the chance of leaks.

Thinking about a new roof or fixing an old one? Try searching roofing contractors near me on Google to find someone who knows how to do the job right.

3. Neglecting Roof Ventilation

When your attic doesn’t get enough airflow, heat can build up fast. That extra heat wears down your roof shingles way sooner than it should. Proper attic ventilation helps a lot—it keeps things cooler up there and cuts down on moisture problems. According to Natural Resources Canada, good airflow in the attic can actually help your roof last longer. 

Signs of inadequate ventilation include:

• Ice dams form in winter
• High energy bills due to heat retention
• Warped or curled shingles due to heat exposure

The fix? Check if your attic has enough vents for both intake and exhaust. This maintains the temperature stable and lets air move freely. Good ventilation not only helps your roof shingles last longer, but it can also make your home more energy efficient.

4. Skipping the Starter Strip

A good shingle roofing job isn’t just about putting on roof shingles. The small details matter too. Take the starter strip, for example. It’s a thin piece that runs along the edge of the roof. Its job? To stop water from slipping under the first row of asphalt shingles. But the truth is, some roofing contractors near you might leave it out—and that can lead to problems down the road. When that happens, here’s what can go wrong:

• Shingles start curling at the edges, making the roof look worn out faster.
• Strong winds can lift the shingles, making them more likely to tear or blow off.
• Water seeps underneath, leading to leaks and moisture damage.

What to Do: Always put down a starter strip along the eaves before putting down the first row of shingles. A small action that helps keep your roof strong and dry.

5. Poor Flashing Installation

Flashing may not be as noticeable as shingles, but it is quite important for keeping your roof watertight. It seals off tricky spots, like around chimneys, windows, and roof dips, so water doesn't get in. Problems normally happen after flashing that isn't done right.

Here are a few common mistakes:

• Reusing old, rusty, or broken flashing instead of swapping it out.
  
  
• Using caulk alone instead of installing real metal flashing—it just doesn’t last.
  
  
• Not overlapping pieces the right way, which leaves gaps for water to slip through.
  
  

What should you do instead?
Use new, high-quality flashing and make sure to install it carefully with the right waterproof materials. It should fit snug, be tightly sealed, and especially hold up well in rainy places like Vancouver. Taking your time on this step can help you avoid major water damage down the road.

6. Inadequate Underlayment

The underlayment is a layer that helps keep moisture out by acting as a backup. If you miss it or buy a cheap one, you could wind up with leaks in your roof or even wood that rots. Using the wrong kind can potentially make your roof's warranty worthless.

Solution: Use good-quality synthetic or felt underlayment that meets the right standards. In fact, the Roofing Contractors Association of British Columbia (RCABC) accepts synthetic underlayment in its RoofStar Guarantee Program because it’s tough and helps keep water out. If you live in a place that gets a lot of rain or snow, adding ice and water shields in those areas can give your roof even more protection.

7. Failing to Follow Manufacturer’s Guidelines

When shingle roofs aren’t installed the way the manufacturer recommends, they can wear out sooner and get damaged more easily. But even when roof shingles are put in the right way, many homeowners still deal with issues in their shingle roofing as the years go by. If you know about these possible problems, you can keep your roof in good shape for a long time. Our guide on 7 Common Problems with Shingle Roofing (and How to Fix Them) has further information. To make sure that the shingles last a long time and work well, each company that makes them has its own set of installation guidelines. Ignoring these guidelines can:

• Void product warranties
• Lead to structural failures
• Result in premature shingle deterioration

Solution: Contractors should always follow the manufacturer’s instructions, including nail placement, overlap requirements, and ventilation recommendations. Homeowners should also verify that the contractor adheres to these guidelines before the installation begins.

How to Find Reliable ‘Roofing Contractors Near Me’ on any search platform

It's very important to pick the correct contractor for a successful roof shingles installation. How do you know you're hiring the finest when there are so many choices? To identify "roofing contractors near me" who can do the work right, follow these steps:

• Check Licenses & Certifications – Make sure you hire a contractor who’s licensed, insured, and actually knows how to install roof shingles. It’s not just about getting the job done—it protects you from problems down the road and helps make sure the work is done right.

• Ask for References & Past Work – A good contractor won't simply talk; they'll also show you. They should include pictures and reviews from customers who have used them for shingle roofing in the past. A quick look at their finished shingle roofs will show you if they are good at what they do.

• Review Warranties & Contracts – A reliable contractor will give you a written estimate, a clear contract, and a warranty for putting on your roof shingles. This ensures transparency and long-term protection.

• Look for Industry Affiliations – Contractors linked to groups like the NRCA or RCABC are usually more trustworthy and tend to follow the right standards for the job.

• Request a Detailed Estimate – They should get a detailed list of the supplies, labor, and any other expenditures, so you know exactly what to expect.

Extra Tips for Homeowners

• Get Your Roof Checked Regularly – It’s smart to have someone check your roof shingles once a year or so. Before they get worse and cost a lot later on, an expert can find small problems early on.

• Keep Those Gutters Clear – When gutters get clogged, water can build up and sneak under your roof shingles. That can lead to leaks and damage. Cleaning them out now and then really helps.

• Check for Storm Damage – After a big storm, take a look at your asphalt shingles. If you see any that are missing or edges that look lifted, it’s best to deal with it right away to avoid bigger repairs later.

Final Thoughts

If installed properly, roof shingles can hold up for more than a decade. But here’s the catch—it has to be done right from the start. When you avoid common slip-ups and hire people who know what they’re doing, your asphalt shingles are more likely to last and protect your home the way they should.

Still searching for roofing contractors near me? Give our trusted crew a call today. We’ll help you build a shingle roofing system that’s made to last.