tunneling vs breaking through slab

Under-Slab Tunneling vs. Breaking Through Your Slab (Pros and Cons)

Oh crap! You’ve got a plumbing leak under your slab and the plumber is asking you if they can break through your foundation to find the problem. Do you even have any options here???? 

Anchor Foundation Repair Bryan College Station

Since foundation repair and under-slab leaks often go hand in hand, Anchor Foundation Repair has 35+ years of experience with how broken plumbing under a foundation can get handled. We understand the stress and anxiety that comes with overwhelming under-slab plumbing issues.

It doesn’t feel like you have any choice but to say yes to busting through your slab (the plumber is probably standing right there staring at you). But you might consider under-slab tunneling for your home situation. This article will compare tunneling vs. breaking your slab by discussing the process and the pros and cons of each.

*Full disclosure* We do under-slab plumbing and are admittedly not big fans of breaking through a slab for many reasons. But we can step back from the situation and provide a fair and impartial list of pros and cons on both sides of this issue. 

Breaking Through Your Slab Foundation (Process)

Most likely, the plumber standing in front of you wants to start breaking through your slab. Here’s what that process looks like:

  1. Seal off and protect the area (hopefully),
  2. Bring a jackhammer inside your house,
  3. Break up flooring and concrete slab with the jackhammer,
  4. Dig out dirt and find somewhere to put it (inside your house),
  5. Fix plumbing leak (hopefully, there’s just the one),
  6. Put the old dirt back in and make a patch to the concrete slab,
  7. Wait for the new concrete to cure/dry (about 24 hours),
  8. Return and clean up the huge mess (hopefully),
  9. Put the floor back down or repair/replace your flooring.

under-slab tunneling prevents this mess
This is just the beginning…

Breaking through a concrete slab foundation is a bit of a *wildcard* endeavor. You never know what you’re going to get. Perhaps I should say it’s like a box of chocolates, and some of the chocolate could be that gross not-very-sweet European stuff.

Not every plumber creates a neat and tidy work environment and cleans up after themselves. Not every plumber will put that big pile of dirt where and how you want it. 

You also don’t really know for sure how many plumbing breaks you have. If there are more breaks or leaks, then they have to keep breaking things up. Before you know it, there could be a lot of holes in your foundation and a pretty big mess on your hands.

Also, the flooring situation can get a bit dicey. Do you have a unique tile or out-of-production flooring type? After the flooring gets taken up, it could be damaged and you’re not able to put it back down again. You might have to replace a section of flooring too. 

Your plumber is not going to be the one to do flooring repairs or replacements for you. Likely, you will have to hire someone else.

The Pros and Cons of Breaking Your Slab to Repair Plumbing

Based on a description of the process, it probably sounds like this approach has no upsides, but that’s not true. The main positives to breaking through your slab are not part of the step-by-step process. The pros are more in the speed and cost departments.

So to be fair and thorough, let’s lay out the pros and cons of pursuing under-slab issues by going through the foundation:

pros and cons

PRO: The plumber is already there and is willing to do the work.

PRO: It could be faster only taking ½ to 1 full day if the leak is easy to locate.

PRO: Less expensive (estimated at $300 to $500 total) if there’s only one isolated leak.

CON: This can easily become a loud and out-of-control mess with dirt and jackhammers.

CON: You might want to move out during the process if it makes key areas unusable.

CON: Even if you stay in the home, there are times you can’t use certain plumbing fixtures.

CON: Higher extra costs with flooring damage and replacement.

CON: If more leaks are found, you have more damage, mess, and cleanup to contend with.

There’s one more con that I am leaving off the official list because it’s more subjective than a true con. It’s that feeling that somehow it seems wrong or bad to cut holes in your foundation. Not that it compromises the structural integrity of your home (because it shouldn’t), but it just *feels* very intrusive. 

There’s a vulnerable, psychological element to this repair approach like it’s not just a piece of concrete that’s being cut into. Maybe I’m just crazy, but I think you know what I mean . . . 

Under-Slab Tunneling for Plumbing Repairs (Process)

Under-slab tunneling is an alternative to breaking through a slab foundation from above to reach and repair under-slab plumbing leaks. Tunnels allow a plumber to repair leaking drain lines under your home without coming inside your house.

tunnel start

Tunneling keeps all the chaos, mess, and people outside and underneath your home instead of on the *inside part* where you like to live. Tunneling allows you to keep using your home nearly normally even while repairs are in progress. Here’s a quick rundown on the process:

  1. Determine tunnel location to reach all plumbing failures,
  2. Plan the path of the tunnel(s),
  3. Dig the tunnel under your home (while you are inside away from the mess),
  4. Fix plumbing leak (hopefully, there is just one),
  5. Fill in the tunnel with backfill dirt (and hopefully mud pumping).

The same thing is true for tunneling as for breaking through your slab: You don’t know for sure how many plumbing breaks you have. If there are more breaks or leaks, then more tunneling needs to occur to reach and repair all the leaks. Anything leaking under your home can cause foundation problems.

The big upside to tunneling is that even with all this tunneling going on, you can carry on with mostly regular life inside your home while they locate and repair all the issues. This is also great for rental properties where you don’t want to disrupt the tenant or provide alternate lodging for them.

We’ve also got a much more detailed article on the tunneling process that you can check out. We also have an article that specifically outlines the experience if Anchor does the project for you. Check out What to Expect from an Under-Slab Tunneling Project on Your Home.

Pros and Cons of Under-Slab Tunneling for Plumbing Repairs

pros and cons

So to keep things fair, we will break down the pros and cons of under-slab tunneling as well. Even though there are *fewer steps* to the process listed above, that doesn’t mean it’s faster than breaking through the slab. 

In fact, it will take longer for tunneling. Tunneling is more of a *carefully proceeding* approach rather than the *smash and grab* approach. But let’s check in on the pros and cons:

PRO: No mess inside your house and no dirt or jackhammers inside either.

PRO: You can stay in the home and use most things normally.

PRO: No flooring damage or replacement.

PRO: Your slab isn’t being tampered with.

PRO: Sometimes home insurance can cover the cost of tunneling to reach plumbing leaks.

PRO: Opportunity for mud pumping to better support your slab after repairs.

CON: Tunneling is more expensive at approximately $300 to $500 per foot.

CON: Takes longer depending on the location and number of leaks (1-5 days).

CON: Many plumbers don’t do tunneling, so you need another contractor involved (like us!).

CON: Even if you stay in the home, there are still times you can’t use plumbing fixtures.

Hopefully, you can see that this is an unbiased list of pros and cons for each approach to reaching your under-slab plumbing leaks. There’s never a perfect option for every scenario when it comes to repairs, there are always upsides and downsides to any choice you consider.

Deciding When Tunneling vs. Breaking Slab is Better for You

home foundation repair

Maybe even after delving into the pros and cons, you’re still *on the fence* about which option is best for you. Here are some guidelines that might help you decide. First up, situations where breaking through the foundation might be your best choice:

  • If you or your plumber are 100% sure there is only one isolated leak, then a breakout would likely be a faster, cheaper option.
  • If the suspected leak is in a remote or easily isolated area of the home that you can comfortably not use for several days, then breaking through the foundation will work.
  • If you’re not currently living in the home due to other major renovations and things are already torn up anyway, break through the slab.
  • If you want to get new flooring in the space in question, this is a great excuse to get the work done and break through the slab.

Situations where under-slab tunneling would work better for you:

  • If there’s a chance you have multiple leaking lines or long rusted-out sections of cast iron drain lines, tunneling might be better.
  • If it would be a considerable daily hardship to not have access to the location needing repairs, i.e. kitchen, your only bathroom, then choose tunneling.
  • If you would rather stay in the house undisturbed by mess and repairmen inside your house, then tunneling will work way better for you.
  • If you have nowhere else that you can go temporarily during the repair process, then tunneling will allow you (or tenants) to easily say put.
  • If you have small children and staying home is way easier than trying to pack them up and take them to an unfamiliar location to live temporarily, choose to tunnel.

More to Consider About Under Slab-Tunneling

Now that you know about the general pros and cons of tunneling vs. slab breaking, there’s one pro for tunneling that I think you should know more about. We mentioned mud pumping a few times in this article but it could use more explanation.


At Anchor Foundation Repair, we don’t fix things that don’t need fixin’, and we don’t try to sell you stuff you don’t need. After 35+ years in business, that’s what’s best for our Brazos Valley community and exceptional homeowners like you. We’re here to help guide you through your home repair process, but you’re the one in charge.

An important part of tunneling under your home is when everything gets filled back in. As a concerned homeowner, you want backfilling done properly to maintain integrity under your foundation. Mud pumping with slurry maximizes structural support after tunneling and not every company employs this tactic. Check out: What Is Slurry and How Is It Used in Under-Slab Tunneling?