What is a Sagging Roof?

The roof is sagging on an old worn brick building. Plants are overgrown around the structure.

Many homeowners may think that a sagging roof is just an eyesore, but in reality, it is a much more serious issue than an unattractive feature. Roofing contractors in Levittown, PA, know that a sagging roof is usually a sign of some serious damage. Therefore, homeowners who want to learn how to fix a sagging roof must first determine what is causing it to occur. If you have a sagging roof on your home, here are three of the most common things that might be causing it.

Excessive Water Damage and Moisture

Your roof plays an important role in keeping your family dry by shielding against extreme weather conditions. However, this may be the reason why your roof is sagging. One of the most common causes of a sagging roof is weakened roof material, usually caused by environmental damage from factors like snow, rain, and ice. 

Over time, the roofing material that makes up the tiles on the top of your home can begin to host water for longer and longer amounts of time. If the water flowing down your roof during a rainstorm does not distribute evenly due to poor design or other functional issues, it can culminate in excess moisture. This, in turn, will cause the roofing materials underneath to decay and sag as a result.

An abnormal amount of moisture can cause other problems for your roof as well. As this rainwater starts to permeate past the initial layer of roofing tiles, mold and mildew can take root in your roof. Should mold grow out of control, it can cause the shingles to erode and rot the wood, further contributing to the degradation of the structure. 

In order to know how to fix a sagging roof caused by water damage, you must identify what is causing the runoff water to flow unevenly. Broken or poorly maintained gutters may be at fault for the excess moisture, or if the sheathing or shingles are causing the unnatural flow, you should have them replaced by experts. Our professional roofing contractors in Bucks County, PA, can help to make sure that your roof is draining rainwater properly, preventing this type of permeation from happening and causing sagging.

Low-Quality Roofing Material and Installation

As you may have noticed in the previous example, one of the ways to fix a sagging roof involves correcting various installation errors. Unfortunately, subpar installation can cause more damage to your roofing than just excess moisture.

You get what you pay for! If a roofer originally installed poor-quality shingles and materials when building the roof, it will naturally not last as long as a higher-quality roof. Low-quality roofing materials can cause sagging because they break under less pressure, allow more water to permeate your roof, and do not hold their shape.

However, even if the materials were of high quality, that does not necessarily mean there won’t be any sagging. One of the reasons why a roof may sag is because the materials used were not fit for the job, such as sheathing that’s too thin or rafters that aren’t big enough. In some cases, an inexperienced roofer may place too many shingles. These design flaws and mistakes will make it so that the roof will be unable to support its weight and sag as a result.

Knowing how to fix a roof with such problems is simple: correct what previous roofing contractors got wrong. Ensure that all of the materials being used are of high quality and are the right size. After your roof replacement, you won’t have to worry about it sagging and collapsing due to another person’s negligence.

Excess Weight From Snow or Ice

While water damage caused by rainwater is one of the many culprits behind a sagging roof, it’s not the only weather condition that can be at fault. If you live in a climate that receives a large amount of cold winter weather, snow and ice can quickly accumulate to dangerous levels on a structure. Your roof was designed to handle a specific amount of weight, and if too much snow builds up, then it can weaken its structural integrity and cause it to sag as a result.

However, before you climb on the roof, know that many people end up doing more damage by removing snow themselves, as they can easily damage shingles or tiles in the process. If you believe that your sagging is being caused by excess snow buildup, call a professional to remove it safely.

Unfortunately, the excess weight your roof is experiencing may not have to do with cold weather, poor installation, or other factors. All roofing materials age, and as they grow older, their structural integrity weakens their ability to withstand the weight that they could in the past. Therefore, knowing how to fix a sagging roof that’s grown too old involves calling for an entire replacement.

If you are dealing with a sagging roof, call our experts at Philly Roofing for more information on how to fix it. In the event that it begins to sag unexpectedly and you need it repaired quickly, you can rely on our emergency roof repair around Philadelphia to resolve the problem. We’re also home to metal roofing contractors in Bucks County, PA, and the surrounding area, among numerous other services. To learn more, don’t hesitate to reach out to Philly Roofing today.


Leave a reply

We pride ourselves in providing you with the
most distinguished roofing services
in the Philadelphia area.


  • This field is for validation purposes and should be left unchanged.


Philly Roofing believes in the "attention to detail." We pride ourselves in providing the most trusted services in the Philadelphia area. We are devoted to our customers under ANY circumstance.

Contact us today to see how we can help answer your questions, solve your issues, and address your concerns immediately!

Get in touch today!