pipe penetration below water line

[fberna]

How do you seal a cast iron pipe coming through concrete when the pipe penetration is below the waterline???

I am going to pour concrete around the shower drain pipe in the concrete slab and create a drywell. However, the rusty cast iron pipe will go through the concrete slab below the water line (during the rainy season). I need to seal the seam between the cast iron pipe and concrete so no water will infiltrate into the drywell I am creating. I have no basement; this is on the ground floor of my home.

Any and all valuable advice is welcome and would be greatly appreciated!

[Amun]

Unless I misunderstand something, nothing you do will stop the water for long. And a cast pipe that is already rusty and sitting in ground water is not going to have a long life.

Why do you need a drywell there ? (shower base ?) Can you change the pipe to PVC ?

you could try the expanding foam in a can they use for windows/doors

AMUN

[willshak]

On 9/1/2005 8:31 AM US(ET), fberna took fingers to keys, and typed the following:

With a hydraulic cement, like UGL's DryLok.

[Art]

Or DAM-IT. They make slow and fast setting. I would go with the slow because it is still very fast. But it will not last forever and neither will that pipe.

[DanG]

I'm a little confused. If the line exits the concrete below the water table, how can anything about it possibly function as a dry well?

Gray water plumbing is illegal in many/most jurisdictions.

To seal a pipe penetration in a concrete wall: drill an appropriate sized hole to allow about a 1/2" annular space. Insert backer rod to proper depth around the pipe, caulk with one or 2 part polyurethane, repair wall waterproofing membrane as required.

None of the expanding foams are waterproof to my knowledge. Cementitious grout packs do not allow for any differential movement between dissimilar materials (cast iron and concrete or pvc and concrete)

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) [e-mail]

[maradcliff]

This is exactly what I was going to recommend. It's made to be installed in water. I have used it, it works great. However, I would not try to use it under a few feet of water, but a little wet is fine. The stuff is extremely hard too. It's costly though, so dont try to pour a basement floor with it.

Mark