New to plumbing - help with utility sink drain and water hookup

[Sam R]

Hey all,

One step forward and one backward and could use some advice!

Recall that I am trying to hook a basement sink up to an old galvanized drain that wasn't being used in the basement (the rest of my house has been upgraded to ABS and drains into our home's main drain above the grade of this sink). By having someone camera through the main cleanout and pouring water down the old basement drain pipe we could see that it did attach to the sewer. So I had a plumber put the sink in using this as the drain. He did a nice job with the sink itself, but didn't test the drain first, and it turns out the old galvanized pipe coming out of the floor drain is leaking right where it meets the floor. More than just a little pinhole... not huge, but fairly rusted out at the base. See the image below again.

The plumber thought someone would have to demo the concrete floor to replace this drainpipe, and would have to move the water heater to get access which is a little more money and destruction than I wanted for a basement utility sink (he estimated 4-5000$ for demo and WH drain/fill). He said a Drainsaurus was another option to pump the sink drain up to the home's main drain.

Since this is just a drain for an occasionally used basement sink I am thinking of just patching where it meets the floor with JB Waterweld, covering the stub of galvanized pipe in some fiberglass plumbing tape/patch, and maybe spraying some flexseal for good measure. I know this might make real plumbers cringe, but can anyone forsee anything catastrophic happening if I take this approach? Do I need to worry about the integrity of the pipe underground meaning I should dig everything up and replace? Again, it is just a slop sink... no toilet or anything else attached to this drain, and I will only be using it occasionally to clean up after messy home projects.

If anyone has another idea I am all ears - I don't know if there is a way to put a liner or ABS pipe INSIDE the old galvanized that might bring the water down without leaking. Don't need something fancy and just hoping to find any solution to drain the sink that doesn't involve a 5000$ expense and torn up floor or a permanent sump bucket.... Thanks!!

 

[Tuttles Revenge]

I look at a LOT of old seattle homes as remodel projects and its very uncommon, even extrememly rare for a steel pipe to be installed below the slab. All the work under ground would have been done in cast iron and likely a bit of the concrete slab got poured around the portion of steel sticking out of the cast iron.

I would investigate whats under the concrete a bit more.. most of the slabs poured in 20's era homes are very thin and easily broken up with a small sledge hammer or chipping gun (always wear eye protection).. If you find cast iron, its not a huge job to remove the small bit of steel and replace it with ABS.

Or as a patch you could epoxy it.. will likely last another 10 yrs or 10 months..

 

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[Tughillrzr]

I’d agree, it’s minimal concrete to remove . It’s in a corner so it’s make it easier too. Just have to see what’s underneath and replace it to abs.

 

[Sam R]

Cool, thanks Tuttles and Tughillrzr! I didn't think that the galvie might be attached to cast iron underneath - super helpful. That should be a simpler job than ripping the whole pipe out and more satisfying/durable than a patch. It's wedged in behind a WH and furnace, but I can probably squeeze back there with rotary hammer or even a masonry chisel/hammer if the concrete is really thin (it is in pretty bad condition back there so might not be too bad). You guys are the best, thanks!