A Bold Statement: Not all plumbing repairs are alike. You might think that’s a strange thing to say considering the fact that the plumbing field has a licensing and apprenticeship system. Don’t they all learn the same stuff the same way??
As a homeowner who knows next to nothing about plumbing, how can you know what to look for when drain lines under your slab foundation need repair? You might want to know more before you can select the best plumbing professional for the job.
At Anchor Foundation Repair, we’ve spent a lot of time under homes during the last 35+ years in business. We dig about 600 feet of tunnel per year to help homeowners reach their plumbing issues. We’ve seen some good plumbing techniques and some bad ones, as well as a few real ugly ones in our line of work. We know what *the good stuff* should look like.
Now, we’re not plumbing experts by any means. Our views are not based on building codes or formal training but based on years of experience, common sense, and job site discussions with some of the top plumbing professionals around.
This article will cover 5 must-haves in under-slab plumbing repairs and what might happen if you *don’t have the must-haves*. We want to set your drain line repairs up with the best chance for success before they are buried under your home again where you can’t see them.
4 Best Practices for Appropriate Under-Slab Drain Line Repairs
Some of these plumbing practices are “to-dos” and some are “not to-dos”. We can classify all of them as ways to best prevent similar or worse problems than you are currently having with your under-slab drain lines in the future.
I would want to have my own under-slab plumbing repaired in a way that best avoids issues in the future. Anchor wants that for your home too. Here’s the quick list of dos and don’ts for the most appropriate drain line repairs that lessen the chance for future problems:
1. No Use of Flexible 2-Band Couplings
2. Limited Use of No-Hub Couplings
3. Use of Clevis Hangers Installed Properly
4. Verify Repairs by Hydrostatic Pressure Testing to Confirm
Now I bet a lot of that is stuff that makes no sense to you, so let’s explain further in the next sections.
1. No Use of Flexible 2-Band Couplings
A flexible 2-band coupling is a plumbing part that joins two pieces of pipe together that might not be the same size or material. It is flexible because it has a rubber sleeve with two metal bands or belts that tighten onto each pipe that is being joined, one band on each pipe. Here’s a picture.
Flexible 2-band couplings are designed to well . . . be flexible, but might work better in above-ground applications in this area. While these couplings are a good way to join two pipes together in other circumstances, under a house in the clay that we have around here is not the optimal environment for a pipe joint that has this kind of flexibility.
Expansive clay soils are so powerful, that they can compromise these kinds of couplings when used underground. I have personally seen these couplings considerably stretched, pulled off, and failing due to expansive clay pulling them apart. A compromised pipe joint equals leaks.
The better choice is a shielded coupling with 4 bands. There is still a flexible inner sleeve, but then a metal shield (typically steel) that is not flexible goes on top of that, and then 4 bands on top of the shield make it extra secure to resist movement from expansive soils underground.
2. Limited Use of No-Hub Couplings
Inside a coupling, there can either be a hub or no hub. A hub is kind of a stopping point inside the sleeve where a pipe inserted into it can only go so far. This stopping point looks like a raised ridge inside the sleeve.
If a no-hub coupling is used, the coupling can slide along the pipe joint in either direction and there is nothing there to stop that from happening. The hub is the stopgap.
If the coupling slides off the pipe joint due to underground forces, then the coupling is not keeping the pipes together. If the pipes become separated because the coupling moved, you get leaks again.
The best choice is using PVC with primer and glue to join things together underground whenever possible. The two-step primer and glue method requires more work but is ultimately stronger, better sealed, and more appropriate in underground applications in our area.
3. Use of Clevis Hangers Installed Properly
Drain lines must run “downhill” so that the water *and stuff* inside them will drain away from your home and move to the sewer system. Under the ground, the drain lines should start high and get lower and lower as they move to connect with municipal sewer lines.
Clevis hangers are metal parts that attach underneath a slab foundation and hold a drain line at its correct pitch (or slant). The hangers should be used every 8 to 10 feet along the drain line path to maintain the correct slope.
Properly installed clevis hangers prevent drain lines from moving out of place and pitch. The hangers keep the drain lines from having low spots that interfere with the natural movement of flowing water.
The key with clevis hangers is not only their use but their proper installation. They need to be spaced correctly as well as create/hold the correct slope. If any of those factors are off, then it can cause stoppages and backflow problems for homeowners.
4. Verify Repairs by Hydrostatic Pressure Testing to Confirm
Hydrostatic pressure testing is a way to locate leaks in plumbing lines but also serves as a way to check that no leaks are present after a repair is made. The hydrostatic test process can also check that the repairs are holding and that no other leaks are present.
When repairs are made and about to be buried underground, don’t you think it would be smart to double-check and make sure that all is well before covering it all up again? Why not make sure that everything is fixed?
You would be surprised at how often re-testing the lines does not happen during under-slab plumbing repairs. In their defense, plumbers sometimes get focused on fixing “that one thing” that is broken.
As a homeowner, you should insist that a hydrostatic pressure test is passed to ensure that no other leaks are present and that the repairs that were done are sufficient. Otherwise, you could very quickly end up in the same leaky boat again.
What Happens to Bad Plumbing Work During Foundation Repairs
If under-slab plumbing repairs are not done using the proper parts and methods, it opens a homeowner up to the same problems happening again: leaks, backflow issues, and possible foundation problems.
No one wants to go through these kinds of drain line issues and the repair process more than once. The best way to avoid repeat problems and repeat repairs is to take a little extra care and time before covering everything back up again.
If foundation repairs are happening along with under-slab plumbing repairs, it is optimal for the foundation repair company to help monitor for best plumbing practices.
If Anchor Foundation Repair sees an issue with under-slab plumbing repairs, we will insist that the repairs are done right for you. This could cause delays and more expense if plumbers have to be asked to return and correct things.
5. Get a Plumber That Knows How to Repair Drain-Lines Properly
No. 5 in the list of *must-haves* for proper under-slab drain line repairs is to get a plumber that has the right experience and know-how for this specific kind of plumbing issue. In other words, get a plumber that can do it right the first time and you don’t have to worry!
At Anchor Foundation Repair, we have been working alongside plumbing professionals since 1985. When homeowners have under-slab plumbing leaks and foundation problems at the same time, we want to make sure you are set up for under-slab success and minimize future issues.
We’ve got a list of great plumbers we have come across and work with frequently. We feel these companies are some of the best equipped and experienced to work under our Brazos Valley customer’s foundations. Check out the 4 Best Bryan-College Station Plumbers for Under-Slab Plumbing Problems.