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Tess
11-23-2010, 01:30 AM
Any Dopers good with home repairs?
I've noticed a dripping PVC pipe in my crawlspace.
The main problem in this case is the drip is where the pipe enters a "T" shaped connection. It looks as if the pipe either wasn't completely fitted to the connection, or the glue didn't set on a small area.
The only way I know to fix this is to cut the leaking pipe and parts of the good pipes downstream on the connection. This sounds pretty involved, and frankly it's probably more than I can competently do. I do have a relative who can do it, but I hate to bother him if I don't have to. Is there any way to fix the leak without losing the decent pipes?
Thanks for any suggestions.

Helix1047
11-23-2010, 02:10 AM
Have you tried caulking?

engineer_comp_geek
11-23-2010, 02:27 AM
You can use a two part epoxy but sometimes that only ends up being a temporary fix because the epoxy doesn't bond well to the PVC. Sand the PVC to make it rough first though and often it will do the trick.

Another thing you can do is to wrap a piece of rubber around the pipe where it enters the T joint and clamp it into place with a hose clamp.

They also make PVC repair kits. The kit has some fiberglass resin tape in it that is water activated. You can get these kits at ye ol local plumbing supply store.

Harmonious Discord
11-23-2010, 05:46 AM
You have to cut out the bad part and replace it. Think of what a mess you'll have and the damage if you need encouragement to fix it. Replacing the section is very quick if you have a PVC pipe cutter. It slices through the pipe like a hot knife through butter.

LSLGuy
11-23-2010, 07:55 AM
The challenge is that he has to replace a T where it sounds like all 3 pipes have limited flex & he doesn't have much room to work. Replacing a pipe run with a crack someplace out in the middle or even replacing a straight coupling is pretty simple.

Cutting out a T, splicing a short straight section onto all 3 lines & inserting a new T in the center while getting each of the 9 joints to ground home solidly is a much more of a PITA. If you have some cool tricks to make that job easy, please share.

beowulff
11-23-2010, 08:17 AM
If you look in the PVC repair section of your local well-stocked hardware store, you will find sleeve-type PVC pipe repairs. These are couplers that snap around a pipe, and are glued into place. So, you can cut the T out of the pipes, and repair without needing any slack. You need to leave some pipe sticking out of the T to allow for the length of the repair sleeve.

FluffyBob
11-23-2010, 09:23 AM
The proper fix really is to cut it out and redo. You can most likely do a temporary fix with some of the appropriate pipe glue. It is thick and does have some gap filling ability, but it is not going to be able to get into the joint where it needs to be, and wont last or may not work at all.

Plastic pipe repairs are relatively easy. PVC is the white stuff, the black stuff is ABS. Both cut easily enough with a hack saw or even wood saw, a pipe cutter does a superior job and will cost around twenty bucks for a cheap one. The glue for each is specific but otherwise works the same, welding the plastic slightly, it is also quite viscous and fills gaps well. If you ever put together a plastic model as a kid, it is like that but easier.

You will need a T, two or three couplers, and a section of straight pipe. Cut out the T close to the joints, or where it is easiest. Choose one of the three sections to be the last to join, it should be the one that has the most movement. You may have to remove some strapping to increase movement. There should be enough play in the pipe to directly connect the T to one section of pipe, the others will need couplers and section of straight pipe. You will need to cut off enough pipe for working room on the sections with couplers.

Start from one section, cutting and dry fitting your pieces till you are happy with the fit. Each joint uses about 1/2" of pipe. Make sure you assemble the whole repair without glue to begin with so you know everything fits, and the easiest sequence to assemble it all. Take your time on this part. Read the instructions on the glue tin and follow them properly. Use plenty of glue, it should squeeze out of the joints so that you know the seal is complete all around. The last joint is the most difficult, you really want enough flexibility in the pipe to make it work.

This repair is not really that difficult or problematic, but if you are uncomfortable with it please just call a professional. Trades work hard to learn what they do and thats what they are paid for.

gaffa
11-23-2010, 12:55 PM
Seconding FluffyBobs suggestion to "dry fit" the parts.

You can cut the pipe with a hacksaw and use couplers on two of them, but the third connection (and possibly the second) may be tricky in a T situation. You might need a Fernco (http://fernco.com/plumbing/flexible-couplings) coupling, a rubber sleeve with metal hose clamps. You can slide it fully over one pipe, then back over the joint.

The main problem is is why it leaks. The main reason PVC joints leak, in my experience, is that they were glued with the wrong cement. PVC "glue" isn't actually glue, but a solvent. And you need to right one to liquefy a PVC surface. If you use ABS cement on a PVC pipe, or vise versa, you will have a joint that will stick....for a while.

Before you make any joint, look for identification on the pipe or connectors to make sure. It should say something like "Sched 40" or "PVC" or "ABS" and get the right cement or glue. And if there is an associated cleaner, make sure to get that as well and clean the joints. Oh, and it is vitally important that the glue be used on both the pipe and the connector.

Dag Otto
11-23-2010, 01:16 PM
First thing we need to know if this is a supply pipe or a drain pipe.

Drain pipes are not under much pressure, but they must be sloped properly. If it is a drain pipe, then a patch type solution may work if you do it yourself. A couple of reasons: it's very likely to be able to stop an unpressurized (or low pressure) leak; and you won't have to concern yourself with changing the slope of the pipes.

If it is a water supply pipe, these are under higher pressure and I'd expect a patch job to probably fail, so replacing the pipe would be better. The good news is that you have some leeway in routing the pipes in order to make everything fit perfectly.

I'd also consider the amount of damage that the leak would cause if it suddenly became a major leak (and also how well you can keep an eye on it to monitor it). The higher the risk the more reason to call a pro. If it's in a place where you are unlikely to notice if it gets worse, same thing - get it fixed right.

gaffa
11-23-2010, 01:22 PM
First thing we need to know if this is a supply pipe or a drain pipe.
Tess' original post said it was a PVC pipe in a crawlspace. 99% of the PVC pipes I see are used for drainage - supply is usually galvanized, copper or Pex. Being exposed in a crawlspace increases the probability of leaks being caused by bad glue joints, as they are exacerbated by cycles of hot and cold weather, in addition to the heating and cooling of the pipe caused by draining baths and showers.

Alpha Twit
11-23-2010, 01:24 PM
I'm going to agree with just about everything FluffyBob said but with one caveat.

If you ever put together a plastic model as a kid, it is like that but easier.

This is both true and not true. The glue works in a similar way but sets much faster. Once you spread it on and push the parts together, you have very little working time before they permanently fuse. Test fit everything. Put it together and take it apart a couple of times before you break out the glue. I'm paranoid enough that I would use some scrap pipe and a fitting to get used to the glue setting speed.

You get one shot at it and if you screw it up, it's back to the hardware store for more parts.

Peremensoe
11-23-2010, 01:29 PM
The proper fix really is to cut it out and redo.
...
This repair is not really that difficult or problematic, but if you are uncomfortable with it please just call a professional. Trades work hard to learn what they do and thats what they are paid for.

This. But, if you can't get to fixing it permanently yourself right away, or can't get the professional service call right away (these next few days may be tough for that), try a stretch-and-seal tape like this (http://amazon.com/Nashua-386-Stretch-Seal-Tape/dp/B000TQEX30), pulled tight with multiple overlapping wraps.

Dag Otto
11-23-2010, 01:35 PM
supply is usually galvanized, copper or Pex.

Or PVC. Or CPVC.

Why assume when you can ask and verify?

gaffa
11-23-2010, 01:58 PM
I can't go along with any suggestion of a "temporary" patch because of the tendency of those to become de facto permanent patches. Fix it right, now. If the OP is worried about gluing:


Get a new T and three short lengths of pipe and three Fercos.
Glue those three short lengths of pipe into the three connectors on the T on your kitchen table.
Place the new assemblage right under the existing T and mark cut lines onto the old pipes.
Cut the three old pipes with a hack saw, cutting out the old T.
Put the T, pipe and Fernco assemblage into place, slip the Ferncos halfway onto the old pipes, half onto the new pipes and tighten. Ideally, use a nutdriver instead of a screwdriver to get it as tight as you can with your hand, but do not use a socket set, as that would be too much torque and would risk cracking the plastic.


If you do this, the worst thing one has to do while in a crawlspace is cut three pipes overhead with a hacksaw (you could use a reciprocating saw if you are very careful, but PVC cuts pretty easily by hand). The gluing can be done where it is easy and where there is good light, and NOT over one's face.

Hopefully this is clear enough. I'd take photos of myself doing this, except I am not near my plumbing supplies.

Tess
11-23-2010, 02:57 PM
Thanks, everybody.
It is a PVC supply line. It's a low pressure leak right now-a slow drip-so the leak's likely a very small spot in the epoxy.
I'm stopping by the local hardware shop tonight for stretch and seal tape and the actual repair supplies. Over the weekend I'll try replacing the section. My brother's fixed some other plumbing issues for me so I'll have backup if things go boink.

Magiver
11-23-2010, 03:42 PM
If I remember correctly there are 2 types of female couplers. One has a divider in the center to stop the pipe from going through and one doesn't. The final connection needs a coupler that allows the pipe to pass all the way through it so it can be slipped on over the existing pipe, thus allowing the new pipe to be brought up next to it.

Dag Otto
11-23-2010, 04:52 PM
Thanks, everybody. It is a PVC supply line.

Then this is something you can do. A supply line is smaller than a drain line (probably 1/2" or 3/4" for a supply line vs a 2" drain line) this will make the fittings much cheaper, so even if you do screw up you can afford to try it again. Buy more fittings than you think you'll need and take the unused ones back later.

Couple of other points. Use both primer and cement, and let the new pipe and fitting set for as long as possible after gluing before turning the water back on (24 hours is good, several hours is probably ok, but 15 minutes is not long enough). And just to be sure, if this is a hot water pipe it is probably CPVC. PVC is fine for cold water service but not for hot water. The pipe should be clearly marked at some point as to what it is.

Finally, use schedule 40 pipe (thinner pipe is available, this is usually for irrigation systems. Don't use it.)

johnpost
11-23-2010, 06:02 PM
cut the straight pipes away from the T, cut back far enough to be able to flex the straight pipes for the replacement procedure. cut out the bad T. reuse the straight lengths attached to the bad T. buy a T and 3 straight couplings. dry fit the pipes with being able to go more than half the potential depth of the couplings. disassemble and glue the T and straight pieces first and then the straight couplings.

is there are short pieces coming from the T and you have no flex then you need to resort to a repair coupling. repair couplings are tricky to work with and need lots of skill.

gaffa
11-23-2010, 10:39 PM
If it's CPVC, you can use Sharkbite (http://sharkbite.com/) fittings. They are more expensive, but you literally push them in like a Tinkertoy and it makes a gas-tight connection as long as you have a straight, flush cut.

gotpasswords
11-23-2010, 11:29 PM
A couple notes from my own experiences...

Get a pipe cutter. They're cheap and the amount of work you'll save by using a pipe cutter instead of any kind of saw will make you glad you bought it - you don't need to mess around with cleaning up a thousand rough burrs that will be left behind after sawing.

One thing that may not be immediately obvious is how to open the cutter - grab both handles and pull them apart and the jaw will open. Some fancy models just need an extra squeeze to release the ratchet, but you'll probably not run into that in the under $20 versions.

Get primer. I'd be willing to bet that the original joint failed because someone was in a hurry and didn't use primer. Done properly, cemented PVC joints should last as long as the pipe itself. I've never tried it myself, but there is "self-priming" cement available. However you do it, just be sure to use primer. Watch out for it though - PVC cement is relatively goopy, but primer is wetter than water and will run along and wick up onto your hands if you're not vigilant. If that happens, your fingers will be stained purple for a few days.

Dry-fitting the pieces is excellent advice. The set-up time for PVC cement is essentially instantaneous. You've got just a couple seconds to push the pieces together before they're solid. One useful trick is to make pencil line-up marks on the pieces - then, once you've primed the pieces, then applied cement to them, start with them rotated 45 degrees from the mark, then as you push the pipe into the connector, twist it to align the marks. Think spiraling, rather than push in and twist.

The twist ensures a good spread of cement, and if the marks line up, everything will fit together nicely like it did on the workbench.

Since you'll probably have to buy much more pipe than you actually need, it would not be a bad idea to get a couple extra cheap fittings to practice a couple joins. Then, when you're in the crawlspace, you won't be worrying that you have no idea what you're doing.

Snnipe 70E
11-24-2010, 12:35 AM
Seconding FluffyBobs suggestion to "dry fit" the parts.

You can cut the pipe with a hacksaw and use couplers on two of them, but the third connection (and possibly the second) may be tricky in a T situation. You might need a Fernco (http://fernco.com/plumbing/flexible-couplings) coupling, a rubber sleeve with metal hose clamps. You can slide it fully over one pipe, then back over the joint.

The main problem is is why it leaks. The main reason PVC joints leak, in my experience, is that they were glued with the wrong cement. PVC "glue" isn't actually glue, but a solvent. And you need to right one to liquefy a PVC surface. If you use ABS cement on a PVC pipe, or vise versa, you will have a joint that will stick....for a while.

Before you make any joint, look for identification on the pipe or connectors to make sure. It should say something like "Sched 40" or "PVC" or "ABS" and get the right cement or glue. And if there is an associated cleaner, make sure to get that as well and clean the joints. Oh, and it is vitally important that the glue be used on both the pipe and the connector.

The Fernco coupling is for use on low pressure lines.

Snnipe 70E
11-24-2010, 12:42 AM
If I remember correctly there are 2 types of female couplers. One has a divider in the center to stop the pipe from going through and one doesn't. The final connection needs a coupler that allows the pipe to pass all the way through it so it can be slipped on over the existing pipe, thus allowing the new pipe to be brought up next to it.

They make those for sodder fittings, but I do not believe they make them for PVC.

Snnipe 70E
11-24-2010, 12:55 AM
No one has mentioned but you can use unions instead of couplers. Depending on how much movement in the pipes you have it will require from 1 to 3 unions.

Rick
11-24-2010, 12:58 AM
I should point out that if your water is hard enough, just put a pan under it. The crap in the water will plug the leak in 6 months or so.
Very redneck and not recommended.

gaffa
11-24-2010, 01:16 AM
The Fernco coupling is for use on low pressure lines.
My recommendation was when it was not clear if the OP was talking about supply or drain, and was assuming drainage.

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