How to Repair a Sewer Pipe Under a Concrete Slab

Do you have a sewer pipe leaking or damaged under your concrete slab? If so, our post today will help guide you through repairing it. With proper support and guidance from experts in this field, it is possible to repair any broken drain line under even the toughest concrete forms — whether a sidewalk, driveway, basement flooring, or another surface.

How to Repair a Sewer Pipe Under a Concrete Slab

If you are in need of sewer pipe repair under a concrete slab, here are some basic steps on how to repair a sewer pipe under a concrete slab.

We’ll look at everything from how to identify issues with existing sewer lines to which tools and materials are required for repairs. So, if you want to save time and money on plumbing issues around your home, read on!

What Will You Need?

Before you repair a sewer pipe under a concrete slab, you must gather the appropriate materials. This includes but is not limited to:

  • PVC cutter or hacksaw
  • Pipe primer and glue
  • Flexible tubing
  • Wrench and pliers
  • Putty knife
  • Level and measuring tape

Once you have gathered the necessary materials, it’s time to start the process.

10 Easy Steps on How to Repair a Sewer Pipe Under a Concrete Slab

Step 1: Locate the Damaged Area

The first step in repairing a sewer pipe under a concrete slab is to identify the precise location of the damage. This is often the most challenging part, as concrete slabs are not transparent. Using specialized tools such as a pipe camera can make this job easier.

Using Specialized Tools Such as a Pipe Camera

These cameras can be inserted into the pipe and highlight areas where damage may occur. Alternatively, signs of damage could include wet patches on the slab or foul odor. Once correctly identifying the damaged area, mark the spot on the slab.

Step 2: Prepare the Area for Work

The next step in repairing a sewer pipe under a concrete slab involves preparing the work area. This is vital to ensure a safe and clean working environment. Clear all items that may hinder your work process from the marked area.

Depending on the extent of the damage, you may need to isolate the area using safety barriers to prevent accidental falls or injuries. Also, wear protective gear such as gloves, safety glasses, and a dust mask before proceeding.

Step 3: Break the Concrete Slab

Once the area is prepared and you’re geared up, it’s time to break the concrete slab covering the damaged sewer pipe. You can use a jackhammer for this process. Carefully start breaking the concrete along the marked area.

Remember that removing a little more slab than necessary is always better to give yourself ample space to work. However, be cautious not to damage the pipe further during this process. Dispose of the concrete pieces safely and ensure the work area remains clean and debris-free.

Step 4: Expose the Damaged Pipe

After removing the concrete slab, you can see the damaged sewer pipe. Use a shovel to remove the soil around the pipe carefully. Be gentle to avoid causing additional damage to the pipe.

Use a Shovel to Remove the Soil

Continue digging until the entire damaged section of the pipe is exposed. It’s important to clear a substantial amount of space around the pipe to allow for easy access during the repair process. Ensure that the area is clean and free from any debris that could interfere with the repair work.

Step 5: Cut the Damaged Section

With the damaged pipe fully exposed, the next step is removing the damaged section. Using a PVC cutter or a hacksaw, carefully cut out the damaged part of the pipe. Ensure that you make your cuts as straight as possible, and always check that the remaining parts of the pipe are in good condition. Discard the removed section appropriately and clean any debris inside the remaining pipe sections.

Step 6: Measure and Cut the Replacement Pipe

After removing the damaged part, you need to prepare the replacement pipe. Using a measuring tape, calculate the length of the pipe you will need to replace the damaged section. Cutting a piece slightly longer than the gap is advisable to ensure a good fit. Once the measurements are taken, use your PVC cutter or hacksaw to cut the new pipe section to the correct length.

Use Your Pvc Cutter

Step 7: Apply Primer and Glue

The next step involves applying a primer and glue to the ends of the existing pipe and the replacement piece. The primer helps clean the pipe’s surface and prepare it for the glue. After applying the primer, apply a generous layer of PVC glue to the same areas. Make sure the glue is applied evenly for a reliable and leak-free connection.

Step 8: Attach the New Pipe

Now that your pipes are primed and glued, attaching the new pipe to the existing drain line is time. Align the replacement pipe with the existing pipes and press them together until the new pipe is firmly in place.

Holding the pipes together for a few moments is essential to allow the glue to set. After the glue has dried, you can check the pipe for any leaks by running a small amount of water through the system.

Step 9: Replace the Soil and Concrete

Once the new pipe is securely in place and there are no leaks, start by replacing the soil you removed earlier around the pipe. Ensure that the soil is compacted to prevent any future shifts.

After the soil is replaced, it’s time to repair the concrete slab. You may need to construct a wooden form to hold the concrete in place while it sets. Pour the concrete mix into the form and smooth it out with a trowel. Allow the concrete to dry completely according to the manufacturer’s instructions.

Step 10: Clean Up the Area

The final step in the process is to clean up your work area. Dispose of any debris appropriately, and make sure to clean your tools before storing them away. Now that your sewer pipe has been repaired, you can enjoy peace of mind knowing you’ve successfully tackled a significant home repair.

Following these ten simple steps, you can easily repair a sewer pipe under a concrete slab. All it takes is the proper materials, preparation, and knowledge to complete the job.

 You Can Easily Repair a Sewer Pipe

5 Additional Tips and Tricks

  1. Know Your Pipes: Before starting the repair, identify the type and size of your sewer pipe. This will help you purchase the correct replacement parts and ensure a proper fit.
  2. Safety First: Always wear proper safety gear — gloves, safety glasses, and durable clothing — when working with sewer pipes. This not only protects you from physical injuries but also from potential health hazards.
  3. Use the Right Tools: Having the right tools can make a difference in this repair job. A reciprocating saw, a pipe cutter, and a pry bar are some of the essential tools that you will need.
  4. Maintain Cleanliness: As you work under a concrete slab, keeping the work area as clean as possible is important. This will help prevent debris from falling into the sewer line and creating additional blockages.
  5. Seek Professional Help if Needed: Repairing a sewer pipe under a concrete slab can be complex. If you need clarification on any aspect of the job, feel free to call in a professional. Sometimes, the cost of hiring an expert may be less than that of a poorly executed DIY repair.

The tips mentioned earlier are incredibly beneficial for anyone embarking on the task of repairing a sewer pipe under a concrete slab. You can navigate this complex task more effectively by knowing your pipes, prioritizing safety, using the right tools, maintaining cleanliness, and seeking professional help when needed.

5 Things You Should Avoid

  1. Avoid Rushing: It’s crucial to take your time with the process when it comes to repairing a sewer pipe under a concrete slab. Slow and careful work will ensure a successful repair and prevent further damage.
  2. Avoid Ignoring Safety Precautions: Never underestimate the importance of safety. Ignoring safety precautions can lead to injuries and other severe consequences.
  3. Avoid Using Inappropriate Tools: It can be tempting to make do with the tools you have on hand, but this can lead to further damage. Always use the correct tools, as mentioned in the guide.
  4. Avoid Neglecting Cleanliness: Overlooking the hygiene aspect can lead to debris falling into the pipes and causing more clogs. It’s vital to keep the work area clean throughout the repair process.
  5. Avoid DIY if Unconfident: This is not a task for the faint-hearted. If you need more confidence in your ability to carry out the repair, it’s best to hire a professional to avoid causing more damage.

By avoiding the common pitfalls mentioned above, you can ensure a more effective and safe repair of your sewer pipe under a concrete slab. Remember, it’s always better to take your time and prioritize safety above everything else.

What Can Damage a Sewer Pipe Under a Concrete Slab?

It’s not uncommon for sewer pipes under concrete slabs to suffer from damage over time. Some of the most common culprits include tree roots infiltrating the pipe, age-related deterioration and corrosion, poor installation practices, and improper cleaning techniques.

It is also important to remember that some materials used in constructing sewer lines can be more prone to damage than others, including cast iron and clay pipes.

 Used in Constructing Sewer Lines

In addition to physical damage, sewer lines under concrete slabs may also suffer from clogs due to the accumulation of debris and waste particles. 

Blockages can also occur due to broken or collapsed pipes, a more serious issue. If not addressed quickly, this blockage can lead to water damage and flooding, so it’s important to take the necessary steps to repair the pipe as soon as possible. With regular maintenance and inspection, you can identify potential issues before they become catastrophic.

By understanding the common causes of damage, as well as knowing how to avoid them, you can ensure that your sewer lines remain in optimal condition.

What Type of Pipe is Under the Slab?

It’s important to identify the type of pipe under the slab to proceed with the repair. Several common types of pipes are used for this purpose, including PVC (polyvinyl chloride), cast iron, and clay. If you need help determining which type of pipe is beneath your concrete slab, you can contact a professional to help determine the best course of action.

You Can Contact a Professional

In addition to pipe type, you’ll also need to consider the pipe size. This information will help inform your repair process and ensure you purchase the appropriate replacement parts.

Finally, it’s important to note that not all sewer pipes under concrete slabs can be repaired. In some cases, it may be necessary to completely replace the entire sewer line, which is a more extensive process.

By understanding the type of pipe and size requirements for your repair job, you can make sure that you have the right tools and materials to get the job done correctly. Knowing these details in advance will save you time and money in the long run!


In conclusion, if the sewer pipes underneath your concrete slab become blocked or broken, there are some things you can do to fix the problem.

First, investigate why the pipe is blocked. If it is due to a tree root invasion or other similar issue, it is important to find out the cause and then begin repairing the location of the impacted pipe.

Second, cut into the concrete slab using an angle grinder and remove damaged sections. Third, use a drain cleaning machine or snake to remove debris blocking the pipe. Finally, install new pipes as necessary and ensure they are sealed properly for water tightness before replacing the concrete slab.

Hopefully, the article on how to repair a sewer pipe under a concrete slab has been useful and informative. Whenever you are dealing with any type of plumbing repairs in your home, always be sure to prioritize safety first. Additionally, if the repair job seems too complex for DIY, it’s best to call in an experienced professional who can help get the job done right! Good luck!

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Terry Alexander

Hi, I am Terry. I started my professional life as a handyman and did a lot of external and internal repair of home and plumbing support. From my childhood, my passion for home repair and fixtures created an opportuinity to pursue a career in HVAC and plumbing industry. As I gained years of knowledge and my love for plumbing grew overtime, I thought to document my journey so that I could help others who ran into daily problems in their home repair. Hopefully it will help you fix those pesky home repair and plumbing problems that always seem to happen at the worst time possible!

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