[Elojr]

6 years ago on this forum, dcsicking used JB Weld to seal the leak in an old cast iron p trap under a concrete slab. I am faced with a similar problem with our shower drain. The drain water disappears completely within an hour, so I assume there must be a leak at the bottom of the p trap U. Any thoughts on sealing this leak? JB Weld? I would like to avoid tearing out the whole shower and slab, as two plumbers have told me that would cost $15K.

Thanks!

[jlisenbe]

This is what the original poster ended up with. I suppose you have already read this. Doesn't sound good to me, but I'd try it before having my shower/tub torn up. I can't imagine this lasting more than a few years, but who knows.

"Speedball1,

Just wanted to let you know that the repair of the corroded shower p-trap worked. I used JB Weld rather than Belzona. I applied 3 packages worth using a snake with a brush that I got from Turbosnake.com. The P-trap remains full now and roaches do not crawl into the shower via the drain."

[Milo Dolezal]

JB Weld is only a quick-fix solution. I would not recommend it. Besides, there is really no way to clean walls of the trap and properly apply it on the interior of the trap. Sorry to say, but the proper way of dealing with such problem is to replace the trap.

If you want to deal with it as an emergency and do some kind of temporary fix - and source of leak is on the bottom of the trap - I suggest that you mix small amount of non-sanded grout ( mix it thin ) and pour it in - just a very small amount so it fills the crack + 1/8". Let it dry for two days. It will fill in the crack and will hold water. The part of the trap, that is constantly wet is the bottom part. So there is an assumption the corroded part is in that area of trap.

If this is my job, I would do it the right way and replace the trap. That is the correct way of dealing with this situation. The repair will not cost you $15K. We have done it several times and it is not such a big deal. Tileman just cuts out 16" x 16" square around the drain, replaces trap, replaces drain, re-seals hot mop, installs new tile - and repair is done. Problem is that the crack in your p-trap can be anyplace within the trap, including in the area that you cannot reach or see. So even JB Weld or pouring mixed grout into the trap would not help.

Hope that helps

Milo

[jlisenbe]

Might be tempted to at least look at the Belzona product, but Milo is more likely on the right track.

Belzona 1831 - Bing video

[Elojr]

JB Weld is only a quick-fix solution. I would not recommend it. Besides, there is really no way to clean walls of the trap and properly apply it on the interior of the trap. Sorry to say, but the proper way of dealing with such problem is to replace the trap.

If you want to deal with it as an emergency and do some kind of temporary fix - and source of leak is on the bottom of the trap - I suggest that you mix small amount of non-sanded grout ( mix it thin ) and pour it in - just a very small amount so it fills the crack + 1/8". Let it dry for two days. It will fill in the crack and will hold water. The part of the trap, that is constantly wet is the bottom part. So there is an assumption the corroded part is in that area of trap.

If this is my job, I would do it the right way and replace the trap. That is the correct way of dealing with this situation. The repair will not cost you $15K. We have done it several times and it is not such a big deal. Tileman just cuts out 16" x 16" square around the drain, replaces trap, replaces drain, re-seals hot mop, installs new tile - and repair is done. Problem is that the crack in your p-trap can be anyplace within the trap, including in the area that you cannot reach or see. So even JB Weld or pouring mixed grout into the trap would not help.

Hope that helps

Milo

Thanks so much for this advice! Is it possible to reseal the hot mop without also tearing out the lower portion of the shower walls, as my contractor has said he needs to do?

[Milo Dolezal]

Elojr: Positive. Both, hot mop and PVC liner are actually quite easily resealable. However, it is important to demo the concrete floor with care and not to damage the water sealing under-layment. Once exposed, cut it with utility knife about 2" from the edge. You will need that edge to make the seal. It is one day project for a patient and skilled handyman. Advice: do not try to match existing tile - as you will never match it. Use different style, different color, perhaps mosaic tile, etc. As far as new trap goes - use ABS glue trap and connect with existing pipe using Fernco coupling. Also, do not reuse old drain - install new drain-head.

Hope that helps

Milo

[Elojr]

Elojr: Positive. Both, hot mop and PVC liner are actually quite easily resealable. However, it is important to demo the concrete floor with care and not to damage the water sealing under-layment. Once exposed, cut it with utility knife about 2" from the edge. You will need that edge to make the seal. It is one day project for a patient and skilled handyman. Advice: do not try to match existing tile - as you will never match it. Use different style, different color, perhaps mosaic tile, etc. As far as new trap goes - use ABS glue trap and connect with existing pipe using Fernco coupling. Also, do not reuse old drain - install new drain-head.

Hope that helps

Milo

Fantastic! I will run this solution by my repair folks for their reaction. Stay tuned. Thanks so much.

[hkstroud]

I assume that this shower is on a concrete slab and you do not have access from below.

[ballengerb1]

So you can see the water level drops completely after an hour, right? Is there a window nearby? If so try opening the window a bit to see if the water in the trap remains. Sometimes a house can develop a negative air pressure due to wind blowing across the vent stack, this could suck the water out of the lowest drain trap.

[Elojr]

I assume that this shower is on a concrete slab and you do not have access from below.

Correct.

So you can see the water level drops completely after an hour, right? Is there a window nearby? If so try opening the window a bit to see if the water in the trap remains. Sometimes a house can develop a negative air pressure due to wind blowing across the vent stack, this could suck the water out of the lowest drain trap.

We have had the window open to reduce to odor in the room.

[hkstroud]

Ever seen the advertisements for this black sealer for gutters and things? In one advertisement they cut a hole in a boat and then cover it with screen wire, then spray with the sealer. I think I have seen it in Home Depot.
I would try some of that, nothing to loose and can't hurt. However I would puncture the can, let the propellant out and then pour it in as a liquid. Turn can up side down and puncture the bottom.

[Elojr]

Ever seen the advertisements for this black sealer for gutters and things? In one advertisement they cut a hole in a boat and then cover it with screen wire, then spray with the sealer. I think I have seen it in Home Depot.
I would try some of that, nothing to loose and can't hurt. However I would puncture the can, let the propellant out and then pour it in as a liquid. Turn can up side down and puncture the bottom.

Do you have a name for this black sealer? How does it differ from an expoxy like JB Weld? Even if temporary, the simplicity of a patch is sure appealing :)

[ballengerb1]

I am pretty certain that punching the can will cause it to explode and you will be injured.

[hkstroud]

Called Flex Seal. Also available at Walmart. Just some kind of thick sealer material in a spray can. Google Flex Seal.

How does it differ from an expoxy like JB Weld

Be more of a liquid, something you could pour down the drain..

I am pretty certain that punching the can will cause it to explode and you will be injured.

No, that should simply let out the propellant, not the material, if can upside down. I suppose you could turn can upside down and let all the propellant out by holding the nozzle

I suppose you could pour about a cup of asphalt sealer down the drain (with the trap dry). That should settle in the bottom of the trap and seal any cracks or rust outs. Might take more than one application.

[Cat1864]

Flex Seal also comes in a non-aerosol type can according to their commercials. But I have only seen it on-line. You may have better luck where you live.

[talaniman]

This is the product referenced

https://www.flexsealsale.com/flxsl/5...3-5287b3b7626d

But I don't recommend it for drain lines you cannot openly access as the likelihood of creating a clog rather than fill a leak, or crack is great.

These products work best from direct application, and dries to a flexible solid that is waterproof. I highly recommend doing this the correct way by replacing the p trap. Without knowing where the crack or leak is exactly is shooting in the dark.

How to Replace a Shower P-Trap | Video | HGTV

Or as a temporary fix inserting a hose or flex tube into the trap

Shower Drain Leak Repair For Condominiums - Pipelining Technologies