Jacking Up a Sagging Roof: 8 Essential Steps You Need to Know

Jacking Up a Sagging Roof: 8 Essential Steps You Need to Know


  Addressing a sagging roof in a flat-roofed house or garage is crucial for maintaining the structural integrity of the building. Lolly columns can provide essential support during the repair process to raise and stabilize the affected area. In this guide, we will explore the steps necessary to jack up a sagging roof, focusing on the use of lolly columns for added support, and provide an overview of the construction aspects of a flat roof house and garage that make this repair necessary.

1.     Assess the Damage: Before any repair work begins, thoroughly assess the extent of the sagging and identify the root causes. This may involve inspecting not just the roof but also the supporting walls and foundation for signs of damage or weakness.

2.     Plan the Repair Strategy: Based on the assessment, plan out the repair process, including the placement of lolly columns to support the roof as it is lifted. Determine the number of jacks needed, their placement, and the amount of lift required to correct the sagging.

3.     Prepare the Work Area: Clear the area beneath the sagging section of the roof. This may involve moving furniture, covering large items with protective sheets, and ensuring that the work area is safe and accessible.

4.     Install Temporary Supports: Before jacking up the roof, install temporary supports (such as lolly columns) to hold the roof in place. These supports will prevent further sagging during the repair and offer additional safety for the structure and workers.

5.     Position the Hydraulic jack: Place hydraulic jacks at the designated points under the sagging area. The jacks should be placed on a stable surface, and it may be necessary to use a strong wooden beam to distribute the lifting force evenly across the roof structure.

6.     Gradually Lift the Roof: Carefully raise the roof by pumping the hydraulic jacks slowly and evenly. This process should be gradual to avoid causing additional stress or damage to the structure. Monitor the progress and adjust the lift as necessary.

7.     Secure the Roof with Permanent Supports: Once the roof is lifted to the desired level, install permanent supports to maintain the correction. This may involve reinforcing existing beams or adding new ones, as well as ensuring the lolly columns are securely in place.

8.     Finish with Inspections and Repairs: After the structural work is complete, inspect the roof and surrounding areas for any additional repairs needed, such as sealing cracks or replacing damaged materials. Ensure that the roof is now properly supported and secure.

Addressing a sagging roof promptly can prevent further damage and preserve the safety and value of your property. By following these steps and using lolly columns effectively, you can stabilize and repair a sagging, flat roof, ensuring it remains strong and functional for years to come.

A close-up image of a cylindrical lolly column supporting a sagging beam in a flat roof house, with strong interplay of shadows.

Step 1: Identifying Sagging Beams

Identifying sagging beams is a crucial first step in addressing the structural integrity of a flat roof house or garage. Joists and beams provide essential support to the roof, and their condition directly impacts the building’s safety and stability.

This step involves a careful inspection to detect any issues that might require attention, particularly focusing on sagging areas that compromise the roof structure.

1.     Inspect Joists and Beams: Begin by examining the joists and beams in the attic or crawl space. Look for visible signs of sagging, such as dips or curves in the beams that deviate from their originally straight form.

2.     Check for Water Damage or Rot: Water damage and rot can significantly weaken the structural components of a roof. Pay extra attention to areas prone to moisture or where rain drainage may be poor, as these are likely spots for damage to occur.

3.     Use a Straightedge or Level: To accurately assess the extent of the sagging, place a long straightedge or a level across the beams. This tool will help highlight any deviations from a flat plane, indicating which beams are sagging and by how much.

4.     Understand the Role of Joists: Joists are horizontal structures that support the roof and floor loads. They play a critical role in distributing weight evenly across the building, and their integrity is essential for maintaining the roof’s structure.

5.     Identify Common Signs of Sagging: Beyond visible sagging, look for cracks, splitting, or bending in the wood. These symptoms can signal weakened beams that might compromise the roof’s integrity.

6.     Consider Rain Drainage Implications: Poor rain drainage can lead to water accumulation on flat roofs, increasing the load on joists and beams and exacerbating sagging issues. Identifying and addressing drainage problems is essential in preventing further damage.

Identifying sagging beams early on allows for timely interventions to prevent more severe structural issues. Joists and beams are the backbone of a roof’s support system, and ensuring their integrity is paramount for the safety and longevity of the building.

Addressing rain drainage problems can also play a significant role in mitigating sagging and ensuring a stable, healthy roof structure.

Step 2: Assessing the Extent of Damage

Assessing the extent of damage is a critical step in the process of repairing a sagging roof. This evaluation is not only about identifying the visible signs of wear or damage but also about understanding the structural integrity of the roof to determine the most appropriate repair strategy.

A thorough assessment ensures that any repair work addresses both the symptoms and the underlying issues, preventing future problems.

1.     Inspect Interior and Exterior: Start by examining both the interior and exterior of the roof. Look for cracked or missing shingles, water stains on the ceilings or walls, and areas where the roof visibly sags. These signs indicate areas that may require immediate attention.

2.     Use a Level for Precision: Employ a level tool to accurately gauge the extent of the sagging across different parts of the roof. This step will help identify the severity of the sagging and pinpoint specific areas in need of repair.

3.     Consult a Professional: Given the complexity of roof repairs, consider consulting with a professional roofing contractor. They can provide an expert assessment of the roof’s structural integrity and recommend the best course of action for jacking up and repairing the sagging sections.

4.     Understand the Importance of a Thorough Assessment: Conducting a comprehensive evaluation before starting repairs is crucial. It ensures that the repair work is targeted and effective, addressing both immediate concerns and potential future issues.

5.     Inspecting Sagging Beams: Employ visual examination techniques and level tools to inspect the condition of sagging beams. This approach helps in understanding the extent of the sagging and the condition of the structural supports.

6.     Consider Alternative Solutions: Depending on the assessment’s outcome, it’s important to consider whether jacking up the roof is the necessary solution or if there are alternative repair methods that could effectively address the issue without extensive structural intervention.

A detailed assessment of the damage is essential for planning an effective repair strategy for a sagging roof. It not only helps identify immediate repair needs but also helps in making informed decisions about the best approach to ensure the roof’s long-term stability and safety.

Step 3: Repairing Sagging Beams in a Garage Roof

Repairing sagging beams in a garage roof involves a meticulous process to restore the structure’s integrity. This step is crucial, especially given the potential load-bearing requirements and the need to prevent further damage to the roof and the overall structure.

Following a systematic approach ensures that the repair work not only addresses the immediate issues but also fortifies the garage roof against future problems.

1.     Assess the Garage Support Structure: Begin with a thorough examination of the garage’s support structure to identify damaged or sagging beams. Look for signs of wear, damage, or deterioration that could compromise the roof’s stability.

2.     Remove Sheathing and Roofing Materials: Carefully dismantle the sheathing and roofing materials in the affected area. This step requires precision to avoid further damage to the structure. Ensure that the work area is adequately protected and that debris is managed effectively.

3.     Repair or Replace Damaged Beams: Once you have access to the damaged beams, evaluate whether repair or replacement is the best course of action. For beams that are structurally unsound, replacement might be necessary. If the damage is minor, repairs may suffice to restore integrity.

4.     Consider Load-Bearing Requirements: When repairing sagging beams in a garage roof, it’s vital to consider any additional load-bearing requirements. Garages often support heavier loads, and the support structure must be reinforced accordingly to ensure safety and stability.

5.     Reinforce Structural Integrity: Before proceeding with the roof repairs, take steps to reinforce the garage’s overall structural integrity. This may involve adding support columns, strengthening existing beams, or installing new support structures to distribute weight evenly.

6.     Replace Sheathing and Roofing: After repairing or replacing the damaged beams, reinstall the sheathing and roofing materials. Follow best practices to ensure that these elements are installed correctly, providing long-term protection and stability for the garage roof.

7.     Guidelines for Material Replacement: Choose high-quality materials for replacing sheathing and roofing to enhance the roof’s durability and resistance to future damage. Ensure that all materials are installed according to manufacturer recommendations and comply with local building codes.

Repairing sagging beams in a garage roof is a complex task that requires careful planning and execution. By addressing the support structure’s condition, reinforcing the garage’s structural integrity, and carefully replacing sheathing and roofing materials, you can ensure that the repaired roof is stable, secure, and capable of withstanding future challenges.

A close-up photo of a metallic bracket securely fastening a wooden beam.

Step 4: Reinforcing Joist Attachment Points

Reinforcing joist attachment points is an essential step in repairing sagging beams and preventing future structural issues. Proper attachment between joists and beams is crucial for maintaining the roof’s integrity and ensuring that it can withstand various loads without sagging.

This step involves a careful examination of existing connections and the implementation of measures to strengthen these critical points.

1.     Inspect Joist Attachment Points: Begin by closely inspecting the points where joists are attached to beams. Look for signs of weakness, such as loose or damaged connections, which could contribute to structural instability.

2.     Strengthen Connections with Metal Plates or Brackets: To reinforce the attachment points, consider using metal plates or brackets. These materials can provide additional support and ensure a secure connection between the joists and beams, significantly reducing the risk of sagging.

3.     Consult a Professional: If you are unsure about the best way to reinforce the joist attachment points or if the repair seems complex, it is advisable to consult with a professional. A structural engineer or experienced contractor can provide valuable insights and recommendations for effectively addressing the issue.

4.     Understand the Role of Proper Joist Attachment: Proper joist attachment is vital for distributing weight evenly across the roof structure and preventing beam sagging. Ensuring that these connections are secure can significantly enhance the roof’s overall stability.

5.     Use Brackets or Hardware for Strengthening: There are various techniques for strengthening joist attachment points, including the use of brackets or specialized hardware. These reinforcements can provide the necessary support to maintain structural integrity over time.

6.     Address Problems Caused by Poor Rainwater Management: Poor management of rainwater on flat roofs can lead to water accumulation, increasing the load on beams and potentially contributing to instability. Ensuring proper rainwater drainage is an important consideration in preventing future structural issues.

Reinforcing joist attachment points is a critical step in addressing sagging beams and ensuring the long-term stability of the roof. By securing these connections and considering additional measures like proper rainwater management, you can significantly reduce the likelihood of future sagging and maintain the structural integrity of your roof.

Step 5: Managing Rain Drainage Effectively

Effective management of rain drainage is crucial in maintaining the structural integrity of flat roofs and preventing issues related to water damage, such as sagging beams. Ensuring that water can efficiently drain off the roof surface can significantly reduce the risk of leaks, water pooling, and the associated stress on the roof structure.

Implementing strategies to improve rain drainage is an essential step in safeguarding the roof against water-related damage.

1.     Maintain Gutters and Downspouts: Regularly inspect and clean gutters and downspouts to ensure they are free from debris. This prevents blockages that can cause water to back up and pool on the roof, leading to increased load and potential damage.

2.     Install a Slight Slope: For flat roofs, consider the installation of a slight slope to facilitate water drainage towards gutters and downspouts. Even a minimal slope can significantly improve water runoff and prevent accumulation.

3.     Add a Waterproof Membrane or Coating: Applying a waterproof membrane or coating to the roof surface can enhance its water repellency and reduce the risk of leaks. This protective layer helps in safeguarding the roof material and the underlying structure from water damage.

4.     Understand the Impact of Efficient Rain Drainage: Efficient rain drainage systems play a key role in preserving the structural integrity of flat roofs. By preventing water accumulation, these systems help avoid excessive load on the roof structure and mitigate the risk of sagging beams.

5.     Solutions for Proper Runoff: Implementing solutions such as additional roof drains, scuppers, or redesigning the roof’s layout can also contribute to better water runoff. These measures ensure that water is quickly and effectively removed from the roof surface, minimizing the risk of damage.

Managing rain drainage effectively involves a combination of regular maintenance, structural adjustments, and protective measures. By ensuring proper runoff and avoiding excessive water accumulation, you can help maintain the structural integrity of flat roofs and prevent common problems associated with poor drainage.

Step 6: Fixing the Underlying Causes of Garage Roof Sagging

Fixing the underlying causes of garage roof sagging is essential to ensure a long-term solution to the problem. This involves a comprehensive approach that goes beyond merely addressing the visible symptoms. By identifying and correcting the root causes of sagging, you can enhance the structural stability of the garage roof and prevent similar issues from arising in the future.

This step is crucial for safeguarding the integrity of your garage structure.

1.     Inspect Roof Trusses and Rafters: Begin by thoroughly inspecting the roof trusses and rafters for any signs of damage or deterioration. These structural elements are crucial for supporting the roof, and any weaknesses can contribute to sagging.

2.     Repair Water Damage and Leaks: Water damage is a common culprit behind sagging roofs. Identify and repair any leaks or areas of water damage to prevent further deterioration of the roof structure. Ensuring the roof is watertight is critical for maintaining its integrity.

3.     Reinforce the Roof Structure: If the existing support structure is insufficient, consider reinforcing the roof with additional beams or braces. This can provide the necessary support to prevent future sagging and enhance the overall stability of the roof.

4.     Address Inadequate Support and Foundation Issues: Common underlying issues like inadequate support beams or foundation problems can lead to roof sagging. It’s important to address these problems as part of the repair process. This may involve strengthening the foundation or adding more supports to distribute the load more evenly.

5.     Understand the Importance of Comprehensive Repairs: Addressing underlying issues in conjunction with repairing sagging beams is vital for preventing future recurrence. A thorough approach ensures that both the symptoms and the root causes are effectively managed.

By carefully inspecting and repairing any damaged structural elements, addressing water damage, and reinforcing the roof as necessary, you can fix the underlying causes of garage roof sagging. This comprehensive approach not only resolves the current issues but also helps in preventing future problems, ensuring the longevity and safety of your garage roof.

A hydraulic jack lifting a sagging wooden beam.

Step 7: Methods for Jacking Up Sagging Beams

Jacking up sagging beams is a critical step in the process of repairing a sagging roof. This process requires careful planning and execution to ensure the safety and stability of the structure. Using hydraulic jacks and lolly columns are among the most effective methods for lifting and supporting sagging beams.

Here, we’ll explore the use of these tools and provide a guide for safely and effectively executing the repair.

1.     Using Hydraulic Jacks: Hydraulic jacks are ideal for providing the powerful, controlled lifting force needed to raise sagging beams. Begin by placing the hydraulic jacks at strategic points under the sagging area. Ensure that the base of each jack is stable and secure.

2.     Incorporating Lolly Columns: After lifting the roof to the desired level with hydraulic jacks, lolly columns can be installed as temporary or permanent supports. These adjustable steel columns offer a cost-effective solution for stabilizing and supporting the lifted beams.

3.     Assess Beam Condition: Before attempting to jack up the roof, thoroughly assess the condition of the beams. This evaluation will help determine the most suitable lifting and support method, ensuring that the chosen approach addresses the specific needs of the structure.

4.     Method Overview: There are various methods available for jacking up sagging beams. Besides hydraulic jacks and lolly columns, other tools and techniques may be used depending on the severity of the sagging and the specific requirements of the roof structure.

5.     Step-by-Step Hydraulic Jack Use: Carefully position the hydraulic jacks under the sagging beams. Gradually pump the jacks to lift the roof, checking regularly to ensure that the lift is even and that there is no undue stress on the structure. Proceed slowly to avoid causing further damage.

6.     Employing Lolly Columns for Permanent Support: In cases where the sagging is severe, lolly columns may be employed as a more permanent solution. Once the roof is lifted to the correct level, adjust the lolly columns to the appropriate height and secure them in place to provide ongoing support.

7.     Necessary Precautions: When jacking up a sagging roof, it is crucial to take necessary precautions to ensure safety and prevent damage. Always distribute the lifting force evenly, and consider consulting a structural engineer to guide the repair process.

Employing hydraulic jacks and lolly columns for jacking up sagging beams offers a reliable method for repairing sagging roofs. By carefully assessing the condition of the beams, choosing the appropriate lifting method, and taking necessary precautions, you can effectively address sagging issues and restore the structural integrity of your roof.

Step 8: Repairing Fiberglass Roofs

Repairing a fiberglass roof, such as that of a Sunrader, requires attention to detail and specific materials and techniques to ensure a durable and effective repair. Fiberglass roofs are unique in their construction and repair needs, especially when dealing with sagging areas that require lifting or jacking up.

This step involves inspecting the roof for damage, using the right fiberglass repair materials, and, if necessary, consulting with a professional experienced in fiberglass work.

1.     Inspect the Sunrader Roof: Thoroughly inspect the Sunrader’s fiberglass roof for any signs of cracks, holes, or other damage. Identifying these issues before proceeding with repairs is crucial for the success of the jacking-up process.

2.     Prepare the Area for Repair: Clean the damaged area thoroughly to ensure that the repair materials adhere properly. This may involve sanding down the area around the damage and removing any debris or loose fiberglass.

3.     Use Fiberglass Repair Materials: Select the appropriate fiberglass repair materials, such as epoxy resin and fiberglass cloth. These materials are essential for creating a strong, durable repair that can support the weight of the roof once it is lifted.

4.     Consult with a Professional: If you are not experienced in working with fiberglass, it is advisable to consult with a professional. Proper technique and the correct choice of materials are crucial for a successful repair of a fiberglass roof.

5.     Apply Epoxy Resin and Fiberglass Cloth: Begin the repair by applying a layer of epoxy resin to the damaged area, followed by placing the fiberglass cloth over the resin. Apply additional resin over the cloth, using a brush to ensure that it is fully saturated and that there are no air bubbles.

6.     Allow for Adequate Curing Time: After applying the fiberglass repair materials, it is important to allow adequate time for the resin to cure fully. The curing time can vary depending on the type of resin used and the environmental conditions.

7.     Sand and Finish the Repaired Area: Once the resin has cured, sand the repaired area to a smooth finish. This not only improves the aesthetic appearance of the repair but also ensures that there are no sharp edges or rough spots.

8.     Inspect and Test for Stability: After the repair is complete, carefully inspect and test the repaired area for stability and strength. This is especially important in areas that will be subjected to the stress of jacking up the roof.

Properly repairing a fiberglass roof on a Sunrader or similar vehicle involves specific considerations and techniques. Using the right materials and methods for fiberglass repair is essential for restoring the structural integrity of the roof and ensuring that it can withstand the process of lifting or jacking up sagging beams.

Consulting with a professional experienced in fiberglass work can provide additional assurance that the repair is performed correctly.


Repairing a sagging roof structure is an essential task that goes beyond cosmetic repair, playing a vital role in maintaining the overall integrity and safety of a building. Addressing this issue promptly and effectively can prevent further damage, avoid potential safety hazards, and ensure the long-term stability of the structure.

It’s important to understand that sagging roofs can be symptomatic of underlying problems that require professional evaluation and intervention.

Consulting with a professional roofing contractor or structural engineer is crucial for accurately assessing the extent of the damage and determining the most appropriate repair strategy. Professionals bring a level of expertise and experience that is essential for diagnosing complex issues and implementing solutions that address both the symptoms and root causes of sagging roofs.

The importance of promptly addressing and properly repairing a sagging roof cannot be overstated. Taking immediate action can prevent minor issues from developing into major problems, thereby saving time and money and ensuring the safety of the building’s occupants.

Proper repair not only restores the structural integrity of the roof but also protects the building against future damage.

In conclusion, if you encounter a sagging roof, it is strongly encouraged to consult with a professional contractor. They can provide a thorough inspection and an accurate diagnosis of the problem, as well as recommend the best course of action to repair the roof effectively.

Taking these steps will help ensure that your building remains safe, secure, and structurally sound.