How To Backfill a Trench After a Slab Leak Repair
Backfilling a trench after a slab leak repair is just as important as the actual repair itself. If done improperly, backfilling can cause more damage than it fixes. I’m here to tell you everything you need to know about the backfilling process!
What is backfilling?
Backfilling a trench is an interesting process that a lot of people don't know about. So first off, what exactly does "backfilling" mean? The process involves sinking an underground tunnel under the house in order to access sewer or water pipes if they have burst, among other things. The soil in Texas is different from most other places because it's made of black clay, which means when things get wet or too dry they expand and contract. This can lead to leaks on your sewer line (or water) that will cost you money!
We're going to come in and perform slab leak detection. After that, we'll locate exactly where the leaks are on either your sewer line or water main; then get into those spots for repairs! After we find out which one is causing problems and make necessary repairs, all of the dirt taken out will need to be backfilled, meaning: the dirt we took out, we want to get as much of that back in as we can. Now it's impossible to get it all back in. You cannot take undisturbed earth, dig it out, put it in a big pile out in the yard, cover it with plastic, wait two or three days and expect it to all go back in. But, you can get about 80-85% of the dirt back in if you do things right.
How does backfilling work?
The dirt is first removed and a trench is formed in order for the plumbers to go in and make their slab leak repair. Inspections are passed, and now it’s time to put the dirt back where we got it. There are different ways to put the dirt back, but what works best for our crews is to use five-gallon buckets to move the dirt back into the tunnel, starting at the the furthest end or furthest part up under the house. They pack it in as much as they can by hand and then take chipping hammers to pack it in tightly. If you’re a plumber, you want to make sure that your water line or sewer line repair is anchored properly so that nothing moves around during the backfilling process.
In Texas, the dirt our houses sit on is a type of black clay, so it’s packed pretty tight. We normally don't have to worry about any dirt sloughing off because of the way that we dig the trenches. Our ditches are normally dug about three feet deep and are shaped like a square. Good thing is, they’re normally dug big enough so that more than one person can go in at a time to work.
What are the challenges of backfilling?
Digging a tunnel is no easy task. You need enough room to get in there and work! When we lay out these tunnels, we want to make sure we have access holes so workers can come up from below without getting stuck because of how cramped it gets. The number of access holes depends on how far the tunnel will go and on where the actual spot is that you are going to perform the repair. We always want to be sure we've got a route of egress. We're going in one way and out somewhere else, so if anything falls in or if you have people working in different areas, everybody doesn’t have to stop to get around them.
Another challenge of backfilling a trench is that you will run into surrounding lines. This is why you should make sure the dig crew you use are all professionals; they will do the job correctly and ensure there are no issues down the line. The obvious issue here is that if another waterline or sewer line is nicked, dented, or damaged at all, the inspection won’t pass.
Is it better to tunnel from inside or outside?
Tunneling inside or outside a house really depends on where the leak is. What kind of flooring is in the house? Will you be able to get the tools inside to perform your repair? For example, if you're replacing a straight sewer line 20 feet deep, and you make a little 2x2 foot hole inside the house and tunnel 10 feet each way; that is going to be really difficult. Can it be done? Absolutely. But remember that you’re going to have to put the dirt that could contain bugs, fecal matter, or raw sewage inside of the house during the process.
The location of the leak is usually the determining factor in price for this process. If the leak is dead center under the house, and I can go through that floor without messing up hardwood, tile, or anything that maybe can't be replaced, that would be a good deal. But think about it, would you want a six foot pile of dirt in your house for days or even a week while repairs are being made? Probably not.
What should I know about backfilling?
First thing to know about backfilling a trench after a slab leak repair: make sure you use a professional crew to perform this job. There have been way too many plumbers to get badly injured - or worse - every year from tunneling up underneath houses. A professional crew will always get a structural engineer to come out and look at it for their workers safety. They will also be able deal with any problems faster which means less time spent fixing things later on down the line.
Normally, a plumbing company has their plumbers go out and dig the trench themselves. That is always something that I said I would never do, I want my tunnels dug professionally. That is something I will always make sure of so that it is safe before me or any of my men go inside there.
The main takeaway I want you to have from this post is to make sure anytime you need a slab leak repair performed: you hire trained professionals!
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