house with a sagging roof

How Much Roof Sag Is Acceptable?

The first line of defense for a home, your roof should be in good condition to keep wind and water from damaging the interior of your home. Sagging is almost always an indicator of a greater problem, requiring professional intervention to prevent continuing damage. But is some roof sag ever acceptable? Here’s what you should know.

When Roofs Sag

When roofs have a wavy or curved appearance, it usually points towards a sagging problem. Typically the result of structural deterioration, this is a common occurrence that appears in houses with roofs that haven’t been replaced in a long while. Sagging is also a common problem in older properties due to the way roofs used to be designed.

Sagging is almost always a bad sign that something worse is on the horizon. But is there ever an acceptable amount? The short answer is that just about any sagging is bad. At bare minimum, it should prompt you to get a thorough evaluation from a reputable local roofer.

Roofs should only sag if they are under a lot of strain from excess weight. Even then, most modern roofs should be strong enough to cope with the added weight without sagging. So, if your roof is sagging at all, you should regard it as a warning sign that means you need to take action.

Why Roofs Sag

There are a variety of reasons why a home’s roof may begin to sag. 

Water damage is one of the most common causes because it impacts the sheathing. When roofs don’t properly distribute water away, excess moisture can cause the underlying roof sheathing to rot which ultimately leads to sagging. In this case, replacing the sheathing with fresh material may be enough to fix the issue.

Utilizing undersized materials is another typical cause of sagging. Something as minor as using 2×4 rafters instead of larger 2×6 rafters can lead to sagging. If there is insufficient bracing, walls may spread over time, which will also cause a roof to noticeably sag. 

sagging roof

Excessive weight on a roof can also cause unseen structural damage due to significant stress. It’s very important to routinely clean away ice and snow from your roof to prevent accumulation. While most of today’s roofs are built to withstand heavy snowfall; large snowstorms and inadequate home maintenance can lead to a weakened internal structure. 

Old age is also a very common cause of sagging. Although proper maintenance will prolong a roof’s lifespan; Father Time will eventually cause the structure to break down and sag. At this point, it’s time to call a professional and have your entire roof replaced. 

Other Considerations

Even the newest, highest-quality roofing materials won’t last forever. On average, a well-built roof will last from 15 to 30 years depending on the roofer, materials, maintenance, climate and design. If your roof is more than three decades old, a new roof is the most effective approach to sagging.

With all that said, problems with the roof aren’t the only reasons why it might sag. If your foundation has started to shift or sink, your roof and walls might have begun to shift with it. In this case, you are likely to notice cracks or tilting in your foundation. To repair significant foundation damage, you will need to talk with a reputable construction professional. If your foundation looks fine, you will need to reach out to a roofing contractor with extensive experience repairing and replacing sagging roofs.

Once a home’s roof begins to sag, it will only get worse over time. Eventually, portions or all of the roof could cave in, causing extensive damage to the rest of your home. It could even lead to serious injury or, in severe instances, death to someone in the home. To protect your property and your family, get in touch with a reputable, experienced Colorado roofing professional who can determine the exact cause of the sagging, expertly assess the damage, and make repair options. The longer you wait, the more expensive repairs will be, so act now before the next rain or snowstorm. 

For decades, A to Z Roofing has specialized in residential and commercial roofing, restoration and repair. A locally owned Colorado business, we’ve operated continuously throughout the Denver metro area and the entire Front Range for nearly a quarter of a century. During this time, we’ve served the needs of homeowners and local businesses, providing expert service using top-quality products. Contact our team of attentive professionals to learn how we can restore, repair or replace your damaged or aging roof.

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