Causes of Roof Sagging and Repair Options

Your roof is essential for various reasons. It protects you and your household from weather conditions while providing insulation and reducing utility bills. Likewise, it provides structural support that keeps your building together. Moreover, a good roof increases your home’s value. These benefits make it essential to ensure that your roof is in good condition. However, it’s not uncommon for roofs to have issues that compromise their integrity. This article focuses on the causes of roof sagging and how you can leverage various sagging roof repair options. 

What is roof sagging? 

Roof sagging occurs when your roof has a wavy or curved appearance instead of a straight one. Sagging is common in homes where the roof has deteriorated structures. Or where the roof hasn’t been replaced in a long time. Older homes also face this roofing problem due to how roofs were once designed. A sagging roof can also indicate structural problems in the future, so keep this in mind. 

What causes a roof to sag? 

If you find yourself googling “why is my roof sagging?” chances are your roof is already in a shape that needs fixing as soon as possible. But what causes a roof to sag? Here are some reasons worth considering. 

Water damage 

Your roof has experienced wind, rain, and snow. While it may be durable, continuous exposure to these elements can cause water damage and compromise your roof’s quality. Because of this, it is important to pay attention to how rain or snow drains from your roof. In addition, clogged downpipes, rusted roof sheets, poor weatherproofing, broken roof tiles, and poor stormwater drainage can also cause water to seep in and cause mold and mildew. This, in turn, can cause a sagging roof and roof collapse if not immediately addressed. 

Substandard materials and poor installation 

While cutting costs and saving more is not uncommon, going for substandard roofing materials can cost you more in the long run. These materials may not withstand the harsh conditions and will cave in sooner than expected. Also, an inexperienced roof installer may poorly fix joints and rafters that would cause your roof to sag under its weight. 

Excess weight 

People who live in snowy areas also risk getting sagging roofs due to the excess weight. Although roofs are designed to hold this weight, leaving the weight of snow on them for prolonged periods can cause sagging. Therefore, regularly removing excess snow from your roof makes sense. 


Irrespective of your roof’s top quality and expert installation, it is bound to age with time. And with age comes weakening and sagging. Ideally, your roof should last between 15 to 70 years, depending on the materials, roof design, and climate. Therefore, age may be the culprit if you notice it caving in. 

How can you repair a sagging roof? 

Fortunately, you can fix a sagging roof and restore it to its original state. Thoroughly examine your roof from the outside and your attic to determine where the sag is most prominent. It’s also helpful to inspect metal or plywood gusset plates for signs of weakness. You can also check for cracks, mold, rot, etc. Sometimes, you can fix a sagging roof by tightening loose rafters, replacing shingles, or adding supports. However, extensive damage requires the services of professional roofers, so keep this in mind. 

If you’re in the Greater Northwest, we’d love to serve you! Our professional roof repair and replacement specialists serve all of NW Oregon & SW Washington.

You can call and get in touch with Western Pacific Roofing at (503) 659-7663 for all your home roofing needs.



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