I ran into a bit of a problem when redoing my 4" main drain.

I replaced about 20' of the drain, but the issue is the pipe coming out of the foundation wall is skewed by a few degrees.

I got the slopes worked out fine, removed the belly in the line, but when I got to the final connection (which is a Fernco strong back rubber coupling, the joint is kinked by a few degrees. Downstream is all solvent welded joints, upstream also all solvent welded joints.







I tested the pipes and no leaks, yet the kinked joint bothered me, because I know inside the coupling, there is a 3/8" gap on one side, like this.



So I thought about it, I loosened the coupling, took a shovel and pushed on one side of the joint hard, and I can get the pipe to flex a little and the two pipes aligned much better, but this caused a 5/16" gap between the two pipes, like this.



So I took a short piece of 4" pipe, and cut myself a "ring" of pipe 5/16" long. I inserted this ring between the two pipes to take up the gap, so it becomes a PVC spacer, like this.



I then put the Fernco coupling over the joint again. Only this time there is a very short 5/16" piece of pipe in the middle of the coupling, and the joint looks a lot better. The coupling is 4" long, each pipe is inserted at least 1-3/4" deep.

I know this is a hack. Can someone give me a good reason to take the joint apart a third time and remake the joint?



Edited 1 times.

all code that i know requires:


..... smooth integral (self scouring) bore .....

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

It has a smooth integral bore now, but it has a very very short piece of pipe inside a coupling to make this happen. Is this short piece of pipe going to be a problem?

is is NOT a smooth integral bore

nor is it a shielded coupling

said coupling would have an integral 'land ridge' against which the pipes would butt MAKING a smooth integral bore




sum, you need to do whatever it takes to make the pipe connections STRAIGHT


perhaps a bend in one of the 'lengths' would help



remove a bunch of the new pipe (two cuts and out in one piece) and work from the house out - AFTER you make the first turn THEN you will have a much much longer piece to 'finnagle' the angles w/o using some rube goldberg coupling/spacer 'thingy'

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



Edited 1 times.

bernabeu,

we are talking about two different things here. I am asking about the kink "correction" (admittedly a hack) by sticking a slice of pipe to make the two pieces align, and the three pieces are being held together with a coupling.

you are talking about whether the coupling I am using is appropriate. Let me address that.

The shielded coupling you are thinking of, I believe, has a thin neoprene sleeve with a ridge in the middle. You install them when in tight spaces, by rolling half the sleeve back like a sock, then you make sure the two pipes meet at the middle ridge, then tighten the shield bands to the required torque. Something like a Fernco PROFLEX coupling, which I have used before. I cannot use these couplings in this situation because it's not legal. Look at Fernco's web site here:

[www.fernco.com]

In it's specifications it stated "...connects cast iron, plastic, steel, copper and tubular, drain waste and vent systems for above-ground applications."

These cannot be used buried below grade, at least not in Florida.

Then there is a family of no hub couplings, also with neoprene sleeves, and SS shields, with 5/16" hex torqued to 80# and four bands instead of two, for heavy duty work connecting cast iron pipes. It doesn't say whether it is designed for above or below ground, and I have tried them once for an above ground connection just for kicks, and I had trouble because the "heavy duty" nature of these sleeves, does not allow them to be folded back. They are twice the thickness of the regular sleeve. Besides they said it is for CI, and the additional "heavy duty" is for connecting the heavier CI. I don't think these are appropriate for buried PVC pipe connections.

[www.fernco.com]

For below grade as far as I know I have to use the thick rubber (no ridge in the middle) type couplings.

The one I am using is an extra heavy duty version of that made by Fernco which they called the STRONG BACK RC couplings, it uses four hex screws, and has an extra SS shear ring for heavy earth load. It is made for buried applications.

[www.fernco.com]

For these couplings, if your pipes meet in the middle then you have the smooth integral bore. If your pipes do not meet and there is a 1/2" gap, then you don't. Same issue if you cement your PVC fitting and you don't bottom to the ridge.



Edited 1 times.

live and learn

but

the rest of the advice still applies



==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



Edited 1 times.

I didn't know that either until I spoke to Fernco on the phone.

Years ago, Fernco made a PROFLEX coupling that connects CI to PVC. It was even available in big box stores. CI OD is a little smaller, so the neoprene sleeve looks almost the same thickness, and I have to carefully measure them ID of the sleeve on each side to make sure which is which, but it works very nicely.

Then one day I was looking to do a 3" CI to 3" PVC on the outside and went to the big box store, they no longer have these special couplings, the new one says 3" CI/PL to 3" CI/PL. I said what? They have gone cheap and got rid of the 3" CI to 3" PL ones?

I then called Fernco directly, because I was thinking may be they still make them, just didn't distribute to the big box stores too many varieties. I told them I wanted information on a special coupling and the customer service rep transferred me to someone in the technical department. They did confirm they no longer made a CI to PL PROFLEX, but then he asked me what I was doing and when I told him I am connecting a 3" CI to 3" PVC in a trench he said "oh no can't use PROFLEXes underground" and he said I have to use the thick rubber couplings which I hated to use, and I said those have no SS shields, he said if I order the STRONG BACK they do.

Sum, thank you so much for sharing your experiences regarding this subject.

yes he's a great contributor of plumbing projects but why not the thank too the veteran and union plumber who contributes way more by sharing his plumbing expertise?

We do appreciate and thank all pros .. see the top right of our page.

I greatly appreciate all the pros here giving their time and sharing their experiences and skills to help me tackle on my projects, I learned so much from here over the years that give me confidence to work on more of my own projects, not only on what to do, but also and more importantly, on what not to do. It's the best place to seek professional advice!



Edited 1 times.

after sleeping on it over the weekend, I have decided to take the joint apart and redo it.

The reason I decided to redo it is because even though the joint is currently aligned, it required an extra short piece of pipe acting as wedge between the two ends to keep that alignment nice and straight. I have never heard of someone using an extra segment like this before inside a single coupling, so I guess that is my reason, so I sleep better at night. Besides, it took me a whole week to excavate that trench where 90% of the time to cut roots away, and a few more days to dig over and over again when rain would wash dirt back into the trench. So what another 2 hours to redo those joints? All I have to do is to remake the 45 elbow with a piece of 4" PVC longer than what I have now plus another 5/16".

On the other hand, I cannot come up with a technical reason why this "hack" wouldn't work.

since you keep using the work "hack" it must be so

? suppose it was a 5/8" spacer ?

? a 1/2 one ?

? a 1/4 one ?




==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

I call it a "hack" because it feels like a hack.

If they do make a 5/16" spacer and that spacer has the same ID and OD as a SCH40 4" PVC pipe, then would I have used it and left it alone? I am not sure.

I have used a spacer to raise a toilet flange to the proper height before and not give it a second thought.

Will I feel better if someone tells me "this wouldn't work because..." or "this is not to code because..." absolutely.

The only thing I can come up with is because it's PVC and the piece only 5/16" thick, and I had to really persuade the other two pipes into alignment (by driving some metal conduits into the dirt in the trench), that "spacer" is under some force wedging against it. I don't know if that force, when combined with expansion/contraction, or forces when I backfill and compact will eventually crack that spacer. If that happens, it may fall into bits over time, and become debris that may block the pipe, and then the gap will return, and no longer has a smooth integral bore. So I guess that's my reasoning for not keeping it this way.

my concept of various spacers was a retorical question

perhaps a better term would have been "gap"

you are correct, it is an additional UNNECESSARY piece, which IMO voids whatever rating the fitting has

the fittings (clamps/couplings) were NOT submitted, tested, nor approved with a 'spacer' inside

therefore they are NOT approved



'nuff said on this topic

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

OK I took everything apart today.

I removed about 14' of the piping so I can widen the trench by about 3" on one side, enough to allow the longest run to shift laterally into better alignment with the upstream segment. I then removed the rubber coupling, used a PVC coupling there instead, and used two rubber couplings downstream to get everything aligned properly. It has no kink horizontally and the slope is good vertically.



I had to use two rubber couplings instead of one because I have to make a precise cut with no gap. I am missing one stainless steel shear ring which I will pick up tomorrow at a supply house. Lot's of Fernco products are on back order.

I will do the leak test tomorrow, then seal off the foundation hole. I might as well do some termicide treatment in the trenches while I have it opened up. Then backfill this weekend.



Edited 1 times.

One final question. When I dug this trench I had lots of trouble with having to cut away tree roots along the way. These roots will grow back eventually.

I am not worried about the PVC solvent welded joints, but I am a bit concerned about these mechanical joints whether they may be source of root intrusion in the future.



Are they OK this way, or should I do something additional as extra insurance? Should I coat the couplings on the outside with roofing tar? Wrapped with aluminum foil tape, spray it with Flex Seal? or just leave it alone as long as the clamps are torqued to 60#-in and these are "Strong Back" couplings and good as advertised?



Edited 1 times.

aluminum foil and flex seal sounds interesting

let us know in 15-20 years how it worked


ps. back fill with sand and tamp it down in such a manner that you can remove the conduit 'alignment stakes'


page 2 'says it all': [usbr.gov]

10" and under pipe: page 54 onwards

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



Edited 1 times.

Good eye that you saw I have a conduit pounded into the dirt to help nudge the pipe into better alignment.

Once I tightened down on those shields and clamps they are not moving anymore, the conduit was already removed after the solvent welded joints cured for a few hours, I didn't want to stress the newly cemented joints.

One lesson I learned is if I have PVC upstream and downstream with no slack or movement, I should just go with two mechanical couplings. My first attempt was to use only one, since I try to minimize mechanical couplings. With the 45 elbow my thought was I could have the 45 pointing up, insert the PVC pipe + 45 + PVC pipe into the PVC hub with primer and cement applied, then roll the piece into position. Well that's very difficult to do and resulted in cutting a shorter piece of pipe.



Edited 1 times.

What happened when you removed the old pipe? Were there roots inside causing the clog?

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Not a plumber by trade but a fierce DIYer

PVC can be heated and bent to almost any angle

PVC can be heat bent for electrical conduit, but not legal to bend plumbing pipe, under the IPC and UPC.