A level roof is crucial for both its structural integrity and its ability to properly shed water. Uneven roofs, caused by anything from improper installation to natural settling, can lead to a cascade of problems. Leaky roofs, warped ceilings, and even structural damage can all stem from an uneven roofline.  Before attempting any repairs, proper diagnosis is key to ensuring a long-lasting solution for your home’s most important shield.

Man working on the roof
Diagnosing the Uneven Roof 

Safety Precautions

Before tackling any roof work, prioritizing safety is paramount.  Always wear sturdy shoes with good traction to prevent slips. Utilize fall protection equipment like a harness and lifeline securely anchored to a stable structure. Working with a partner provides an extra layer of safety, allowing someone to spot you and assist in case of a fall.

Visual Inspection

The first step in diagnosing an uneven roof is a thorough visual inspection.  Begin by observing the roofline from the ground. Look for any noticeable dips, sags, or areas that appear crooked compared to the rest of the roof.  Next, move on to a close-up inspection. Examine the shingles for signs of buckling, curling, or missing pieces.  Check the fascia board (the board at the edge of the roof) for warping or looseness.  Finally, venture into the attic if accessible. Use a flashlight to inspect the underside of the roof sheathing (the plywood base under the shingles) for signs of water damage, warping, or rot.  Look for any cracks in the rafters, beams, or trusses that may indicate structural issues.

Tools for Measurement

To confirm and quantify unevenness, a few key tools come in handy.  A carpenter’s level helps determine if a surface is flat.  Place the level along the roofline or on the attic floor joists to identify any slopes or dips.  A straightedge, a long, flat board, can be used to check for warped roof sheathing or misaligned fascia boards.  A tape measure allows for precise measurement of any gaps, dips, or misalignments.  Finally, a plumb bob, a weight suspended on a string, can be used to check for vertical misalignment in walls or support structures.

Common Causes of Uneven Roofs

  • Improper Installation: Mistakes made during the initial roof construction can lead to unevenness.  This could include uneven spacing of trusses or rafters, improper installation of flashing around chimneys or vents, or neglecting to properly secure the roof sheathing. 
  • Settling Foundation:  Over time, a house’s foundation can settle unevenly.  This natural movement can cause the roof structure to shift and become uneven.  Signs of foundation settling may include cracks in the foundation walls or uneven floors inside the house. 
  • Water Damage: Leaks from damaged shingles, clogged gutters, or faulty flashing can lead to water damage in the roof structure.  Rotting wood due to moisture exposure can cause sections of the roof to sag or become uneven. 
  • Structural Issues: Damaged trusses, rafters, or beams can cause dips or sagging in the roof.  These structural components can be weakened by age, overloading (such as heavy snow accumulation), or improper construction techniques. 
  • Weather Events:  Heavy snow accumulation or strong winds can put a significant amount of stress on a roof.  This stress can cause the roof structure to sag or become uneven over time.

Man working on the roof wearing a helmet and vest
Fixing Uneven Roofs

Considerations Before Fixing 

Before diving into repairs, a careful evaluation of the situation is crucial. The severity of the unevenness plays a major role. Minor dips, especially those within acceptable tolerances, might not require extensive repairs.  However, for more pronounced dips, sagging sections, or any signs of structural issues, professional intervention is highly recommended.  Safety is paramount when dealing with roof work, and complex repairs often involve specialized tools and expertise.

The cost of repairs can vary significantly depending on the severity of the problem and the chosen solution. Factor in the cost of materials like shingles, lumber, or flashing, as well as labor costs for professional help. Additionally, depending on the extent of the repairs, permits from your local building department might be required.

Fixing Minor Unevenness

  • Shingle Issues – Unevenness caused by loose or buckled shingles is a relatively simple fix. Carefully remove the damaged shingles and replace them with new ones, ensuring proper nailing according to manufacturer’s recommendations.  Pay close attention to flashing around chimneys, vents, or skylights, as these areas are particularly prone to leaks.  Ensure proper installation and sealing of flashing to prevent water infiltration behind the shingles. 
  • Fascia Board Repair – A warped or loose fascia board can contribute to a visually uneven roofline.  For minor issues, removing and replacing rotten sections with new, pressure-treated lumber might be sufficient. Ensure the fascia board is securely fastened to the roof trusses and maintains a straight line along the roof edge. 
  • Gutter Adjustments – Crooked gutters can create the illusion of an uneven roof. Realigning the gutters to ensure a proper slope towards downspouts is essential for efficient water drainage.  Secure any loose gutter brackets and clean out any accumulated debris to prevent clogs and overflows. 
  • Minor Sagging – For very slight dips in the roof sheathing (typically less than an inch), shimming might be a viable option.  This involves placing thin wedges of treated wood under the affected area in the attic to level the surface. However, it’s crucial to ensure the dip doesn’t indicate a more significant structural issue requiring professional attention.

Fixing Major Unevenness

Unevenness caused by structural problems, severe water damage, or foundation settling necessitates professional repairs. Here are some common scenarios and potential solutions:

  • Structural Repairs – Damaged trusses, rafters, or beams require the expertise of a qualified roofer or structural engineer. Depending on the extent of the damage, repairs might involve jacking up the roof structure to regain proper alignment.  Severely compromised components will need to be replaced with new, structurally sound lumber. This process is complex and requires specialized lifting equipment and engineering knowledge. 
  • Roof Sheathing Replacement – If the unevenness originates from warped or rotten roof sheathing, replacing the affected areas becomes necessary. Professionals will carefully remove the damaged sheathing and ensure proper ventilation in the attic space before installing new plywood sheets.  They will then re-install the underlayment and shingles, ensuring a watertight and structurally sound roof system. 
  • Re-roofing – In cases of widespread unevenness, extensive water damage, or nearing the end of the roof’s lifespan, a complete re-roofing project might be the most prudent course of action. This involves removing all existing shingles, underlayment, and potentially even the roof sheathing.  Qualified roofers will then install a brand new roof system with proper waterproofing and ventilation to ensure the longevity and performance of your roof. 
  • Foundation Repair – Unevenness caused by foundation settling requires addressing the underlying foundation issue.  Consulting a structural engineer is crucial to determine the most appropriate solution. Common foundation repair methods include piers or pilings, which are essentially support posts driven deep into the ground to stabilize the foundation and prevent further settling.  This process is complex and requires expertise to ensure the long-term stability of your home.

Preventative Measures to Maintain a Level Roof 

An ounce of prevention is truly worth a pound of cure when it comes to maintaining a level roof. By incorporating these simple yet effective practices into your home maintenance routine, you can significantly reduce the risk of unevenness and extend the lifespan of your roof.

Regular Roof Inspections

Schedule annual inspections by a qualified roofer to proactively identify potential problems.  These inspections should include a thorough examination of the roof surface for missing or damaged shingles, loose flashing, and any signs of wear or tear.  The inspector will also check the attic for signs of moisture intrusion, inadequate ventilation, or potential structural issues. Early detection allows for prompt repairs, preventing minor problems from escalating into major structural concerns that could lead to unevenness.

Proper Attic Ventilation

Maintaining proper ventilation in your attic is crucial for preventing moisture buildup, which can lead to wood rot and ultimately contribute to roof unevenness.  Adequate ventilation allows trapped moisture to escape, preventing condensation on the underside of the roof sheathing.  Ensure your attic has sufficient ventilation through a combination of soffit vents (located under the eaves) and ridge vents (installed along the peak of the roof).  If your attic lacks proper ventilation, consider consulting a qualified roofer to discuss installation options.

Addressing Drainage Issues

A properly functioning drainage system is vital for preventing water from pooling on your roof.  Schedule regular cleaning of your gutters and downspouts to remove leaves, debris, and blockages.  Clogged gutters can cause water to back up under the shingles, leading to leaks and potential roof damage that could contribute to unevenness.  Additionally, consider installing gutter guards to minimize debris accumulation and reduce the frequency of cleaning.

Trimming Overhanging Trees

Overhanging tree branches pose a double threat to your roof.  During heavy storms, these branches can scrape against the shingles, causing physical damage and potentially creating entry points for water leaks. Additionally, leaves and debris from overhanging trees can accumulate on the roof, clogging gutters and hindering proper drainage.  Schedule regular trimming of overhanging branches to maintain a safe distance from the roof and prevent them from causing damage that could contribute to unevenness.


A level roof is not just aesthetically pleasing, it’s crucial for the structural integrity and weatherproofing of your home. An uneven roof can lead to a cascade of problems, including leaks, warped ceilings, and even structural damage. These repairs can be costly and time-consuming.  Proper diagnosis is key to finding the root cause of the unevenness and choosing the most appropriate solution.  Ignoring the problem can lead to further deterioration and potentially compromise the overall health of your home.

In addition, incorporating preventative measures like regular inspections, proper ventilation, addressing drainage issues, and trimming overhanging trees, you can significantly reduce the risk of unevenness and extend the lifespan of your roof. A proactive approach will save you money in the long run and ensure your roof continues to effectively shield your home from the elements for years to come.