Understanding and Addressing Sagging Roofs

Why Does Your Roof Sag?

A sagging roof is a common issue, especially in homes with older roofing. If you notice the ridge of your roof dipping, it’s a sign that the roofing structure isn’t adequately supported. Addressing this issue can range from straightforward solutions to more complex procedures. Unless you’re a roofing contractor, it’s wise to enlist the help of a professional.

Breaking Down Roof Structures:

1. Rafter Roofs:
   • Description: Rafters are the structural components of a sloped roof, essentially forming a right-angle triangle in basic gable roofs. Rafters are the angled boards that meet at the peak, while the horizontal boards below are the rafter ties or sometimes the ceiling joists.
   • Issues & Causes: Sagging often arises due to insufficient internal bracing or undersized rafters.
2. Truss Roofs:
   • Description: Modern homes often use trusses instead of rafters. Trusses are pre-engineered with more internal supports, allowing for smaller lumber pieces.
   • Issues & Causes: Sagging in truss roofs can be a result of undersized trusses or inadequate internal bracing.
3. Flat Roofs:
   • Description: Contrary to the name, flat roofs have a slight slope for drainage and resemble standard floor frames.
   • Issues & Causes: Sagging may arise due to weakened joists or problems with layers beneath the surface.

Common Causes of Roof Sagging:

1. Water Damage: Improper drainage can lead to moisture seeping into the sheathing, causing rot and subsequent sagging.
2. Undersized Materials: Using structural components smaller than required can accelerate roof sagging.
3. Excessive Loads: Accumulation of heavy snow, ice, or multiple layers of shingles can strain the roof.
4. Old Age: Despite maintenance, roofs naturally degrade over time.

Addressing a Sagging Roof:

Fixing a sagging roof demands expertise. The right solution depends on the severity and cause:

• For rafter-style roofs, strengthening internal framing is common. If roof replacement is due, larger rafters might be installed.
• For truss-style roofs, replacing problematic sheathing is standard. But for major issues, consulting the home’s builder is wise.
• Always consult an experienced structural engineer or builder before making any modifications.

At KM Roof and Home Repair, we prioritize your home’s aesthetics, durability, and energy efficiency. Whether you’re facing minor repairs or considering a complete replacement, our experts are here to help. Contact us today!