Gray Roof Shingles

5 Reasons Your Roof Shingles are Curling and the Fixes

In Technical Details by Giovanni ValleLeave a Comment

You put a lot of money into your house. In fact, your home is probably the biggest expense you’ll make in your life. You want it to last. When you start noticing the shingles on your roof start to curl, you want to know the reasons why and how to fix it.

The reasons why your roof shingles are curling could be due to a larger issue. There are five main reasons why your roof shingles could be curling.

  • Improperly Installed
  • Poor Ventilation
  • Age
  • Bad Materials
  • New Roof Installed Over an Old Roof

The shingles on your roof are curling for a reason. You want to know why and how to fix them to prevent any further damage. Let’s first find an answer for why your roof shingles are curling and then we can see what can be done to fix them

What Is Going on With My Roof Shingles

There are two ways to describe what you are seeing happening to your roof shingles. Both are used pretty much interchangeably, but there are some subtle differences between the two descriptions.

  • Curling
  • Buckling

Curling is the most common of problems with roof shingles. Curling is when the corners of the shingle come loose and “curl” up. Curling shingles will expose the roof underneath which could cause further damage to your house. A curling shingle usually indicates a problem with the shingle itself or the way the shingle was installed.


Buckling describes a shingle that is raised in the middle. A buckle is formed when moisture is trapped under the shingle. This is most probably an indication of poor ventilation.

Curling and buckling are the most common phrases used to describe the problems with your roof shingles. You may also hear the phrase “fishmouthing” or “blistering”. Fishmouthing or cupping refers to when the edges of the shingle rise up slightly in the middle. Blistering refers to the bubble or blister that occurs when gas tries to escape from the layers under the shingle. Whatever you call it, it means your roof needs to be repaired.

Identifying the Reasons Your Shingles are Curling

Inside your home you may have seen water leaks or notice sunlight in your attic where there shouldn’t be. The curling or buckling roof shingles on the outside of your house could be symptoms or even causes of the problems you are seeing on the inside. Let’s take a look at the reasons behind the damage.

Improper Installation

The most common reason for a curling roof shingle is that whoever installed them did not follow the specifications needed for proper installation. Shingles come with specific instructions for installation. In addition, building codes should always be followed when installing a roof.

  • Too Few Nails Used: In normal circumstances, you should use four nails for each roof shingle. For houses in high wind areas, six nails are suggested for each roofing shingle. Using too few nails will mean the corner of the shingle will not be completely flush and be susceptible to being pulled up and away from the roof.
  • Wrong Nail Length: A roofing nail should be long enough to fully connect with the underlying layers of materials underneath. Lengths run from one to two inches. Some nails can be as long as six inches. You don’t want the nail to be too short that it doesn’t lock in place. But you also don’t want the nail too long where it cannot be flat against the roofing shingle.
  • Cheap Nails: The standard recommendation for nails is to use galvanized, zinc-coated, steel nails with a barbed shank. While it really should depend on what is needed, some roofers use smooth shank nails made of cheaper materials to save on costs. This could mean problems down the road and may be the reason behind your curling shingles.
  • Nails Used in The Wrong Place: The location of the nails when the contractor installed your roof could be the reason behind your roof shingles curling. If the nails are too far off where they should be, the edges of the shingle will gradually pull away, causing curling.
  • Roof Shingles Not Aligned Properly: Each asphalt roof shingle has a tar line. This tar line is an adhesive that keeps the shingle in place. If the roof shingles are not lined up correctly, they will eventually come loose. You would see this as your shingles are curling at the edges.

Poor Ventilation

Another top reason your roof shingles are curling is due to poor ventilation. The moisture that builds up in your house must go somewhere. That somewhere is normally up, towards the ceiling and then the attic. If you have poor ventilation in your attic, the moist air gets trapped between the underlying materials that protect and insulate your roof and attic. This could grow mold and mildew and cause all sorts of problems. It can also affect the shingles on your roof.

Technically, the escaping moisture causes the shingle to rise in the middle making it buckle not curl. For all intents and purposes, they are very similar problems and you will need a professional to take a look and repair the damage. To prevent further problems in the future, you should investigate what is preventing the moisture from escaping.


We all get older and your roof is no exception. Some roofing shingles are sold with a thirty, forty, or even a lifetime warranty. While a longer warranty is definitely a benefit, most roofs will need to be replaced long before the warranty has expired.

A roof will normally last no more than twenty-five years. Some may need replacing around ten to fifteen years but most need to be replaced around twenty years. Although some shingles are better quality and do tend to last longer, a harsh environment will cause a roof to age more quickly. Heavy storms and intense heat are factors in what is causing your roof shingles to curl.

With every growing technology, roof shingles installed today will most likely last longer than roofing shingles installed twenty years ago. But basically, things just wear out. If your roof is over ten years old, be proactive and check it periodically for curling shingles and other possible signs of wear and tear.

Defective Materials

While most manufacturers strive to make a quality product, there are times where they have missed the mark. As a result, some shingle companies have been in the news and involved in class-action lawsuits around the country.

In some cases, the shingles started to curl shortly after they were installed. In that situation, the manufacturer stopped making and selling the defective roof shingles. Other companies acknowledged there may be an issue but made revisions to the product and covered replacements under their warranties.

If your roof was installed recently and you have noticed curling on your shingles, your first step is to get it inspected. You should then try to contact the manufacturer and then your insurance company.

Things to know:

  • Your warranty may be affected by the installation of the roof shingles.
  • Some insurance companies refuse to cover houses that have roof shingles from certain companies.

New Roof Installed Over An Old Roof

Let’s face it, replacing a roof is expensive. Most homeowners want to save money where they can. Rather than completely removing the defective roof, some homeowners will install a new roof over the top of the damaged roof. This may save money initially, but it is not recommended and may cost the homeowner money in the future.

The problem is that the new roof will not be as secure as the old roof. This means the new roof is more susceptible to curling and buckling sooner than expected. The old roof was probably replaced due to some sort of damage. If that damage was rot or mildew, it may still exist and cause damage to the new roof as well.

How To Fix Curling Roof Shingles: Repair or Replace

There are times when repairing parts of a roof makes more sense than replacing the whole roof. If you are trying to decide which route to go, consider the amount and size of the damage as well as the age of the roof.

  • A Few Damaged Shingles
  • Single or Multiple Areas
  • The Real Costs of Installing a New Roof Over an Existing Roof
A Few Damaged Shingles

If you have lost a few roof shingles due to heavy winds or a strong storm, repairing your roof and replacing those few damaged shingles may make more sense. If, however, there is damage to your roof shingles like curling, you want to consider the underlying cause of the damage.

Before making your decision, you should consider the age of the roof as well. If you are unsure which direction to go, contact a roofing professional for an estimate.

Single or Multiple Areas

If the damaged roof shingles are in one large area, or several smaller areas, you should consider not only the age of your roof but also the aesthetics. Your roof is a very visible part of your house. If you replace parts of it rather than the whole roof, will you be able to match the other shingles? This is not only a question about what you feel comfortable with, but it will also affect the resale value of your house later down the road.

Type of Damage

Repairing a small section of your roof when the damage was caused by strong winds is different than repairing a section that has curling roof shingles. You want to make sure you are not covering up damage in a small area that may cause more extensive damage later.

The Real Costs of Installing a New Roof Over an Existing Roof

Installing a new roof over the existing one is not recommended but it can be done. Depending on the situation, it may be acceptable. Most local building codes allow for two layers of roof. More than two roofing layers can damage the framework and structure of the house.

While it may seem like a cheaper way to go, adding another layer over the current roof, will most likely end up costing you more money. When you are considering repairing a section rather than replacing the whole roof, you want to weigh the overall costs.

Labor costs: The installers will already be working on your roof. They will have their scaffolding and ladders in place. The installers will need to pull off the damaged section and replace that. They then will need to install new roof shingles over the entire roof.

Compare the costs of all that work already going on to install a second roof over the existing one. Which is really more cost effective?

Time value: Are you in a rush? If you are replacing the roof due to leaks and emergency issues, then maybe a second layer is a good solution for the moment. If you can, an investment of your time now may help you save money later.

If it costs $4500 to repair a section of your roof but $6000 to replace the entire roof, it just makes more practical sense to do the whole roof replacement. This is especially true if your roof has some age on it and will need replacing within the next few years anyway.

Types of Asphalt Roof Shingles

Roof shingles can come in a variety of materials. Each type of roofing shingle has its advantages and disadvantages. Costs can range from the expensive slate to the more affordable, and therefore more popular asphalt.

  • Slate
  • Wood
  • Clay
  • Metal
  • Composite
  • Asphalt

Asphalt roofing shingles are the most economical material for roof shingles. Asphalt roofing shingles were invented in 1903 by Henry Reynolds in Grand Rapids, Michigan. At that time asphalt shingles were made of cotton felt soaked in asphalt to make them waterproof and coated in asphalt to allow ceramic granules to attach to the surface. Later the cotton felt was replaced with paper felt.

Fiberglass asphalt roofing shingles were developed in the 1980s and quickly became the more popular choice. Fiberglass shingles are made of a fiberglass base. As in the organic asphalt shingles, the surface of the fiberglass roofing shingle is coated with asphalt adhesive which is then covered with ceramic granules.

Organic asphalt shingles are considered more durable and contain approximately forty percent more asbestos than fiberglass shingles. Organic shingles are heavier than fiberglass roofing shingles.

Fiberglass roofing shingles are more fireproof and lighter than organic roofing shingles. Fiberglass shingles are the more popular choice these days.

Styles of Asphalt Roofing Shingles

Asphalt roofing shingles come in two basic styles:

  • 3-tab
  • Architectural

3-Tab roofing shingles are made in a single layer and are flat and uniform. They are thinner and less durable. 3-tab roofing shingles generally need to be replaced anywhere from 15 to 18 years and have a shorter warranty period.

Architectural roofing shingles are thicker and come in a variety of shapes and colors. Also called dimensional, architectural roofing shingles allow for more customization and are becoming more popular despite the added costs. Architectural asphalt roofing shingles are expected to last at least up to thirty years and have a much longer warranty period.

How To Maintain Your Roof

Having a house is a big investment. You want it to last a long time. That means regular maintenance starting at the top with the roof. These five steps should be added to your routine house maintenance checklist.

  • Keep your roof free from debris: Remove any sticks or twigs.
  • Clean your gutters and drain spouts: This is to ensure water does not back up and start to push its way under your shingles.
  • Watch for moss build up: Moss needs water to grow and holds that moisture next to your roof.
  • Inspect your shingles yearly: Look for any curling or buckling and investigate the reason behind any problems.
  • Insulate your house well: Proper insulation will keep moisture build-up to a minimum and that will ultimately protect your roof.

Pay Attention To Your Roof

Your house is your home. Most people want a home that looks as good as it is comfortable. Your roof is a big part of the aesthetic of your house. If you are going to eventually sell your house, your roof is one of the most noticeable features of your house. A great looking roof can make a strong first impression

There are a lot of things that could cause damage to your roof. These range from the preventable to the unavoidable. Some of these issues are predictable and you can add their costs to your house maintenance budget. If your roof is under warranty, certain problems may be covered.

The main thing to remember though is that when you see something like your roof shingles curling, you need to act fast to find the reason behind it and fix it. Curling roof shingles can be costly of ignored but if caught in time, the financial impact can be minimized.

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