Plumbing Job- Is this bid fair, need advice. Under slab

[innkeeper77]

Hello! I have a plumbing issue, and need advice. We have a rental home in Aurora Colorado, which we personally lived in for a few years. I messed up and didn't notice the furnace never had a condensate neutralizer installed, which then ate up some cast iron plumbing under the basement slab... oh well, what's done is done. What I need is advice to see if the bid I got is reasonable, and any plumber recommendations if it isn't reasonable. I have three bids and really don't know what the best course of action is. I can pay the full amount, but the top proposal is up to $17,000 which is a bit much and I don't want to overpay if it isn't smart..

I have attached a photo with the diagram of the situation. The washer drains into the main stack (1) and the furnace has a long pvc line to the existing floor drain in front of the washer. These combined are causing a MINOR flooding situation, most water drains but there is a standing puddle between the washer and the stairs at all times.

The cast iron line goes from the main stack (1) out of the foundation (3) which then meets up with modern replaced drain line (replaced prior to us buying the place)

Additionally, the pvc line is annoying and bad, so I asked for the floor drain in front of the washer (which is old and corroded anyway) to be relocated to next to the furnace (2) to avoid the long annoying PVC run. This is a tenant quality of life issue, so I will do it no matter what, and since any option will involve concrete, this is the best time to do it.

The main issue is a blockage right under the main stack, but the plumber recommends doing the whole line (of course) because of avoiding future issues (which honestly sounds valid)

Estimates:

1. $4050: Just the main issue plus new floor drain relocation: The option is to replace floor drain and relocate it next to furnace. Will need to jack hammer concrete from 3" main stack. Will tie in to 3" underground line and place new floor drain next to furnace (about 7ft). All work to be done in ABS pipe and fittings. Once repair is complete we will test for leaks and backfill/compact trench. Includes concrete replacement where it was removed. 2 year warranty on repair only 


2. $11,500: Cast iron drain line replacement under basement floor: This option is to replace all under ground cast iron drain lines. Will include all underground tie ins from main stack to foundation wall and will include new floor drain relocation. Will need to jack hammer concrete (about 30ft) for the access of removal and replacement of new drain lines. All work to be done with new abs pipe and fittings. Once repair is complete we will leak test, backfill & compact trench. Concrete will be patched were removed. 5 year warranty on repairs only.

3. $17,000: This option is to completely replace cast iron drain line under concrete and to exterior where sewer line was previously replaced. Will include all underground tie ins from main stack to exterior and will include new floor drain relocation. Will need to jack hammer concrete (about 30ft) for the access of removal and replacement of new drain lines in basement. At exterior we will excavate down to cast iron connection and will replace back towards basement. All work to be done with new abs pipe and fittings. Once repair is complete we will leak test, backfill & compact trench. Concrete will be patched were removed. Includes city permit, inspection and comes with a 5 year warranty on repairs only.


Thank you so much for any input or advice!

[Sibley]

You have 1 quote for 3 separate jobs. They are not comparable. Step 1: figure out which job you want to do. Step 2: Get 3 quotes for that job and compare.

As for which job to do, what's the condition of the plumbing? You know there's problems under the concrete. What about the drain line that is outside? What's its condition? Keep in mind that jackhammering anywhere could cause problems for pipe that you weren't planning on touching.

Personally, I would go with job #2 or #3. Because if you're doing concrete work, just do all of the concrete work so you don't need to worry about it in future. For the line out to the sewer, that would depend on current condition. Have you had these lines camera'ed?

[sonofsven]

Well, it isn't really three different jobs, it's three different approaches to the same job.
If the condensate draining into the cast iron is causing issues with the cast iron then it doesn't make much sense to leave any CI in the floor. If, however, you can stop the breakdown of the CI through the use of a condensate pump neutralizer then it's not unreasonable to simply remove the damaged pipe with new where necessary, as in option 1.
Options 2 and 3 differ only in their language regarding how to transition from the pipe under the house to outside the house. Option 3 wants to dig down and expose the pipe outside the house and make the connection there, option 2 says they will replace the pipe all the way to the foundation, which is less clear. Sometimes the foundation is sleeved so the pipe can can be installed after the pour, but I suspect since it is cast iron the pipe was laid out in the trench and the concrete was poured around it.
What you don't want is all new piping inside and out with connections to old pipe that is still laid in the foundation.
So I would say option 2 will likely become more like option 3 with a change order utilized once they see what needs to be done.
Similarly, with option 1, it's a little unknown now exactly how much piping needs to be replaced so that price might change depending on what they find.
It's hard to say which option I would choose because I work with plumbers I trust, so I would likely go with the option my most trusted plumber laid out.
If you trust plumber option 1 then I would lean towards that one, just know that costs may increase depending on what they find when they open it up.