Below are videos of my cast iron drain pipes from 2021 and then again about 18 months later after being snaked twice (for same clog) of toilet paper because the toilet leaked from the base and a plunger didn’t work.
Seeking your advice to evaluate 3 options:

1.) Do nothing (each toilet will have bidet seats and minimal toilet paper to be used)
2.) Clean them and see what they look like after (what is the safest method for this?)
3.) Spend $15-20K from my emergency fund now to replace accessible ones with PVC and use Perma-Liner CIPP for the rest. There is about 120ft total of drain pipe in the house.

March 2021
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August 2022:
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I’m currently in the middle of a light renovation before moving in, with a limited budget remaining as it has gone on much longer than expected.

If possible, I would like to wait until after moving in and saving more money, but am concerned waiting too long could result in the harder to reach pipes becoming ineligible for CIPP. Breaking the slab inside and trenching will cost a lot more than $20K after restoration.

Additional Details: Single family home of about 2000 sq. ft. built in late 1950s. Location is Miami, FL. Septic tank is in good shape and was replaced a few years ago. Drywall for 2 of the 4 vent stacks is already open during the renovation and they’re accessible if needed.

What did your plumber recommend when he did a video inspection
That pipe is 73 years old, that’s old enough for me to recommend replacing it especially since the house is unoccupied at the moment
In my opinion if you can afford it now replace it now
Who wants to move into a newly renovated house then be inconvenienced down the road by the mess and headaches of construction

Thanks for your reply. I received a few quotes and each plumber agreed that action will be needed eventually, but didn't really want to estimate a timeframe. I asked 5 of my neighbors and none have needed to replace or line theirs. Similar style homes and build year, but I'd imagine these things can vary house by house.

What do you think about a low risk intermediate step like jetting (or even better if something gentler) that can allow a look at the condition underneath the buildup?

Multiple of the lining companies offered to credit the price of a cleaning now back towards lining work in the future. My concern is that they'd be incentivized to do it roughly and leave me with no option but to line or replace now.

There are several steps you can do to get more info

From my experience, which is limited since I am a DIYer and not a pro, the worst condition of all the pipes will be the kitchen line. People pour all kinds of stuff down there, grease, oil, food waste, boiling water, coffee grounds, acidic stuff, alkaline stuff and the stuff sits there and form soft blockages and people added chemicals like Draino to clear them. This is repeated over and over. I would expect your kitchen line to represent the worst case scenario. You could inspect that and get a good idea.

The vent sections - the vertical sections above the sanitary tee fittings are they galvanized iron (gray color) or cast iron (black color), those are usually fine even after so many years.

You can jet clean and do a video inspection, but if you have a belly at all, water will be pooling at the bottom and you can't see much. After all, the bottom of a pipe is where you really want to to see because that's where the cast iron pipes start to fail.

CIPP lining how would they handle the smaller drains that tie into the main drain? Are they going to be able to cut new holes through the main drain lining? Fifteen years back I had a drain that needs replacement and the lining folks said they can line my 4" main but they do not have a way to do my 2", the technology is not there yet, so they have to open the slab between two points with no tie in and dig down to line one section at a time. Perhaps technology has been much improved now. I end up doing a total replacement with tunnel under the house, no mess and no dust, I am in south Florida (Broward) you might want to consider that as an option as well.

Thanks for your reply.

The vent sections - the vertical sections above the sanitary tee fittings are they galvanized iron (gray color) or cast iron (black color), those are usually fine even after so many years.
>>>The stacks themselves are cast iron and appear to be ok. My understanding is that with CIPP or spincast epoxy they can be lined as well.

CIPP lining how would they handle the smaller drains that tie into the main drain?
>>>My (limited) understanding is that they can use Perma-Liner for the main line, do a reinstatement process like this: [www.youtube.com] and then they line the branch and reinstate it again. They said that some parts may need to be done with spincast epoxy from Picote, but the majority with Perma-Liner.

Perhaps technology has been much improved now. I end up doing a total replacement with tunnel under the house, no mess and no dust, I am in south Florida (Broward) you might want to consider that as an option as well.
>>>I heard that there is risk to the foundation with that approach? How did it work out for you and may I ask what the price was? I hear that A1 Underground is popular for this down here with proprietary rock blasting trucks, but apparently they don't do Dade County.

I spoke again with my plumber today and he said he believes I won't have issues with doing CIPP in the future so there's not an immediate rush. So I think I'll wait for now and then jet it lightly instead of snaking when I next get a clog, based on this plumber's guidance.

"I heard that there is risk to the foundation with that approach? How did it work out for you and may I ask what the price was? I hear that A1 Underground is popular for this down here with proprietary rock blasting trucks, but apparently they don't do Dade County."

For me, it solved my problem. This was in 2015, and yes I also had sewer liner companies come do an estimate but their solution, in addition to the complication with the side branches, was the need to go inside the house to cut open a 3X3 hole and go 3' deep in order to start the liner from there to the outside. That is a big mess and will create other issues like I don't have spare floor tiles to cover the 3X3 hole that they will tear up, and that hole is right under existing kitchen cabinets, so are we going to remove counter tops, cabinets to make way? All of that was part of the consideration. Also bear in mind if you do a liner, the liner will adhere to the shape of your cast iron pipe on the inside, so if you have a bunch of corrosion that make the inside of the cast iron budging irregularly, you need to have another step performed to scour the cast pipe round again and jet off all debris, the scouring is typically done with a jet machine fitted with a chain nozzle that spins at high speed. This is most likely additional and not cheap either.

You are correct that a tunnel of this size may cause issue with the foundation. However, not always. If you have a monolithic slab home which is likely in south Florida, your home is not really supported by the soil underneath it, it is supported by footings that goes deeper around the perimeter of your home, and there are footers below some of the interior spaces as well, the soil helps. Over time, the soil will settle. Sometimes independent of the slab, sometimes with the slab. I have cut open concrete slabs inside houses and it's not uncommon to see the actual soil below the slab being two inches below the bottom of the slab due to settlement. Secondly, at least where I am in Broward County, the city requires when you tunnel like this the contractor proves that the soil density of the new soil placed in the tunnel is at least the same as the soil density of the soil they excavated. This is done by a soil engineering report of a soil sample taken before and after excavation (which in itself is a useless exercise for sake of waiving liability). They excavated the tunnel not manually, but with water jet shooting into the tunnel, then a vac truck sucks the wet muck out. After laying the new pipes, they have a pressure truck to shoot wet sand into the tunnel theoretically at a high compaction.

Cost wise, I think the tunneling cost $8000 back in 2015. The backfill with another truck shooting wet sand was another $3000 I think, the soil engineering report was $3000 or $5000 I don't remember, plus permits and fees it was around $18000 total when it's all said and done.

Here are some threads I posted about it at the time with pictures. That may help to get some visuals.

[www.plbg.com]

[www.plbg.com]