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-   -   Double Bowl Kitchen Sink Drainage Problem (http://www.diychatroom.com/f7/double-bowl-kitchen-sink-drainage-problem-113351/)

PeteW 08-08-2011 12:19 PM

Double Bowl Kitchen Sink Drainage Problem
 
Hi, I'm Pete. I just joined the DIY Chatroom this morning. You'll find my intro in the Introduction Forum. I'm hoping I can be of some help to others, but for now I need some myself. :laughing:
I own a house that I've been preparing for the rental market. It was need of some significant work. So far most of it is done, but I have a problem in the Kitchen which I would like to correct before renting it.

The Double sink does not drain properly. If I add fill up either sink and try to drain it the water will back up into the other sink and they both drain slowly.
I know this should not happen this way. My memory is a bit fuzzy on this part so please bear with me. Naturally I'm expecting some follow up questions, but here is the best information I can offer to get us started. I have had this problem addressed by professional plumbers at least three times when my father was still living in the house.

As I remember I was told that it had something to do with the venting or possibly how the the sink drain line connected to the main drain line.

The house is a track home (single story ranch on slab) built in Virginia Beach, Va in 1973. The plumbing is copper supply lines and (now) partly pvc to metal drain lines beneath the sinks, but originally they must have all been galvanized metal, including P-traps, per evidence under one bathroom sink.

The Main Drain line is cast iron. The Kitchen is on the back side of the house and the sinks are below a large chest high double window. Facing the sink the from the kitchen it drains from left to right. A garbage disposal (1 year old) is on the left sink. This dishwasher (right side) drains to the Garbage Disposal. The Right sink bowl drains directly into the drain and the P-trap is below it.

The drain line elbows from the P-trap and back into the wall from there. The old drain line from inside the outside wall has been cut and fitted to the pvc drain line, from the sinks, with a rubber pressure connector and hose clamps.
This was done a couple years ago by a plumbing company.

Further to right about 8' away the main drain line begins (or ends depending how you look at it) where it accepts the washing machine drain. The main is 3 or 4 inches and runs below and along the back edge of the concrete slab (draining right to left). Between the washing machine drain and the kitchen sinks drain is where the 1 1/2" or 2" vent pipe exits the roof above the eave.

Both bathrooms are at the left end (along the left side) of house where drain line curves and runs from the back to the front of the house picking up the two bathrooms. It exits from beneath the house near the left front corner and travels diagonally to the Right across the front yard to the city sewage connection at the street.

About a year ago after a backup I had the main drain scrapped all the way to the street and some roots were removed. I followed this up with a camera inspection and looked at the entire drain line from the washing machine drain back to the street.

It was clear and water was flowing as it should. The vent pipe located between the kitchen sinks and washing machine was also supposedly cleaned again at that time (although I personally don’t remember checking it). In spite of this the kitchen sink has remained a problem.

I'm replacing the dishwasher and the sink countertop so while I have them out of the way I thought it would be the very best time to address this issue and hopefully resolve it. I fully expect to cut the wall out to access the sink drain inside the wall. I know that the challenge will be replacing the rest of the sink drain and connecting to the old cast iron main drain. This will involve some digging to get to it beneath the slab.

The good news is that the back of the house is totally accessible (no bushes), so that shouldn't be a problem. All of this said, can I get some advice on how to proceed from there. I don't have much plumbing experience, dealing with large old fragile pipes.

Also, although I have no recollection of my parents ever complaining about drainage problems with the kitchen sinks while they were alive I'm wondering if it was just an issue they put up with. Could the placement of the vent pipe be the problem?

The following link should open a drawing I'm providing.
Hopefully, I've made this pretty clear and the experts out there can give me some needed advice.

VIPlumber 08-08-2011 07:03 PM

Quote:

Could the placement of the vent pipe be the problem?
Hi Pete,

Sounds like you're getting to have all the fun.:sweatdrop:

A couple of quick questions;
1) How far is the distance between the the vent and the drain for the sink?
2) Do you know how many other vents you have? (i.e.-This relates if you have slow drains in other parts of the house.) Also curious about what else drains into this particular line.
3) Do you have access in the attic and crawl space to take pics and post? If the connections to the drainage are a problem, then pics from the crawl should help us help you. And there may be a series of vents connected in the attic before it goes through the roof, hopefully there will be enough to accommodate the houses' needs.

Andy.

PeteW 08-09-2011 10:46 AM

Quote:

Originally Posted by VIPlumber (Post 703185)
Hi Pete,

Sounds like you're getting to have all the fun.:sweatdrop:

A couple of quick questions;
1) How far is the distance between the the vent and the drain for the sink?

Hi Andy,

Like you say Fun, Fun, Fun!:eek:

Figuring pictures might be helpful I actually took some yesterday after my initial post. Based on the pictures and my observations it appears that the kitchen vent pipe is 3' from where the sink drain connects to the main drain based on where the vent pipe exits the roof. The vent is located between the Washing Machine and the Kitchen sink drain.

Quote:

2) Do you know how many other vents you have? (i.e.-This relates if you have slow drains in other parts of the house.) Also curious about what else drains into this particular line.
It appears as though there are three plumbing vents. The other two are located at the other end of the house and are for the bathrooms. Probably should have shown them in the diagram.

Quote:

3) Do you have access in the attic and crawl space to take pics and post?
I did not get any attic shots. The kitchen vent is to close to the eave to even get a decent picture, but as you can see I did get outside pictures which I hope are adequate.

Quote:

If the connections to the drainage are a problem, then pics from the crawl should help us help you. And there may be a series of vents connected in the attic before it goes through the roof, hopefully there will be enough to accommodate the houses' needs.

Andy.
Sorry, the house is on a slab, but I believe the drain line is just under the edge of the slab and with a bit of digging I should be able to access it without to much trouble. I can get pictures from the attic if necessary, but I've never had a drainage issue with the bathrooms. Mostly I want to fix this so I'm not getting midnight calls from future tenants. At least not as meany midnight calls. :laughing:

Thanks, for taking an interest in my problem.

Pete

VIPlumber 08-09-2011 11:16 PM

Hey Pete,

Sorry for the delay, but it was long day. I'll reply tomorrow.

PeteW 08-10-2011 06:24 AM

Sure Andy, I understand. I hope all is well.
Pete

George6488 08-10-2011 10:02 AM

I recently had a similar problem. My problem / solution was located where the new kitchen PVC tied into the old galvanized line. There was a large and very solid clog in the galvanized piping which was removed with some difficulty. It appeared that the horizontal run did not have enough pitch and the solids from the disposal were building a deposit where the drain transitioned from horizontal to vertical.

I later went back and opened up the wal and replaced most of the galvanized with PVC using a Fernco adapter. All has been well for over 3 years.

My suggestion would be to remove the adapter and take a look inside.

VIPlumber 08-10-2011 06:06 PM

Hey Pete,

George stole my thunder with the suggestion of removing the ferno before the pipe enters the wall and having a look at the what's going on in there. i.e. - Is there any build up?

Also you might want to change the slope of the drain from the garbage disposal to the T. Looks pretty flat to me. The slope into the wall looks good from what I can tell. It should all drop 1/4" per foot.

Seems to me that all your groups, bathrooms and kitchen, vent separately which should make isolating the issue a little easier.

Another thing to try is checking the vent from the roof. It's not unknown to have something, debris, etc... fall in and slow it down. Get a flashlight, garden hose and a trusty helper. Sometimes it's hard seeing down the vent from the roof, so a towel over your head might cut the glare from the sun down enough to see if there's anything in there. The hose would be try and wash down what ever is in there and the helper is to yell at you to turn the water off, just in case .

Galvanized pipes are known to clog up over time, especially water supply ones. I've not seen it used in drainage but assume that it will clog as well, just at a slower rate.

In pic 5 you show your washer set-up. I'd suggest adding some water hammer arrestors to your hot and cold lines, and changing the washing machine hoses to the braided stainless steel ones, if you don't have them already.

Well, gotta jet, but I'll be back a little later.
Andy.

PeteW 08-10-2011 11:18 PM

Quote:

Originally Posted by George6488 (Post 704218)
I recently had a similar problem... PVC tied into the old galvanized line... large and very solid clog in the galvanized piping... the horizontal run did not have enough pitch and the solids from the disposal were building a deposit where the drain transitioned from horizontal to vertical.

...opened up the wal and replaced most of the galvanized with PVC using a Fernco adapter. All has been well for over 3 years.

My suggestion would be to remove the adapter and take a look inside.

Quote:

Originally Posted by VIPlumber (Post 704559)
Hey Pete,

George stole my thunder with the suggestion of removing the ferno before the pipe enters the wall and having a look at the what's going on in there. i.e. - Is there any build up?

Also you might want to change the slope of the drain from the garbage disposal to the T. Looks pretty flat to me. The slope into the wall looks good from what I can tell. It should all drop 1/4" per foot.

...try is checking the vent from the roof. ...The hose would be try and wash down what ever is in there and the helper is to yell at you to turn the water off, just in case .

In pic 5 you show your washer set-up. I'd suggest adding some water hammer arrestors to your hot and cold lines, and changing the washing machine hoses to the braided stainless steel ones, if you don't have them already...

Thanks guys,:thumbup:
Very helpful info. The day I took the pictures of the back of the house it occurred to me that I can just remove the siding and cut out the brown fiberboard, which I'm sure was used as exterior sheathing back in 1973, and get total access to the inside of the wall. I need to replace the starter row of vinyl siding and the outside corner posts anyway due to UV and weed eater damage. I have already purchased the siding and OC's for that. So now I'll just go up a few rows higher in that area. This way I can really see whats going on and work on it from both sides of the drywall. I will definitely check the vent. My neighbor told me the other day that he has an electric drain snake. If I'm not certain the hose has done the trick, then I'll borrow it. I will correct any slope problems, I see what you are saying about the line connecting the GD and the second sink. I also seem to have a vague memory of a plumber telling me that the pipe being to flat before going vertical was probably the problem inside the wall. My ex-son-in-law's plumbing company did the work and I think they just stopped short of correcting the entire problem. Anyway, I certainly appreciate your help. I'll probably have a few more questions once I get the wall open. Either way I'll be sure to follow up with pictures. Might be a couple of days, so get some sleep.:laughing:

Pete
ps I have the braided hoses but I'll look into the hammer arrestors. I was already thinking about replacing the water valves with the better 1/4 turn ones.

PeteW 08-16-2011 07:06 PM

Okay so I took opened the outside wall. Here are the pics of what I found.

I'm thinking replace everything down to the stub sticking out of the slab with PVC. What do you think and please let me know if the slope is enough for the Kitchen drain line.

VIPlumber 08-16-2011 11:21 PM

Hey Pete,

Welcome back, looks like you've been busy.

You're right, the slope does seem a little thin (bubble should be ~1/4 over the line) and you might be able to improve it a bit by wedging up the far right, near the elbow. If that doesn't work then I'd go with your idea of cutting the stub from the slab a little lower and see what you get. That means sawzalling all the holes progressively lower, and with that triple stud on the right hand, I don't envy you.

Since you've already opened the wall, and the cast iron is close to 40 years old I'd suggest replacing the drain lines with Schedule 40 (or Schd 80 if it's too noisy) ABS, the elbow from the KS and the sani T's, dry fit loosely and then glue from the sani T backward to the KS. No need to replace the vent unless you think there might be a problem. It looks pretty good to me. And the replacement will involve removing the pipe clamp in the attic by the eave and possibly fixing the roof.

Maybe I'm missing something and someone else can chime in with their $0.02.

Andy.

PeteW 08-17-2011 10:12 AM

Hi Andy,
Never let it be said that Pete is afraid to make a huge hole in a perfectly good wall! :no:

Thanks for taking the time to offer your expertise. I Guess there really should not be a problem with the vent pipe as it mostly just stays dry. I will inspect it today.

From what you have suggested I'm guessing the schedule 80 being thicker must help insulate the noise of the draining water. I haven't really noticed a big problem with noise, but then it's been cast iron until now. At the time I buy the pipe I'll check the outside diameter and let that be the final factor, to get that extra slope without a lot of sawzalling.

My brother-in-law also knows a plumber well so I'll ask him to get and opinion on this.

Well maybe by the end of the day I'll have so positive news to relate.

Pete

PeteW 08-22-2011 02:14 PM

Project completed. Well at least the out side part. Here is the link. I still need to complete the inside sink connections as soon as I install the new counter top.

VIPlumber 08-22-2011 10:59 PM

Hey Pete,

Glad to hear that you're on the home stretch! Too bad you didn't remember to test the line before you closed up the wall. If you primed, glued, twisted the pipe on a 1/4 turn and held for the suggested 30 secs (like it says on the glue bottle), then you should be golden. I hope.

Pics 16 & 17 are the clearest indication of the draining problems you were having. Looks like the lines needed a good, good cleaning. Or replacing, as you did. On that note people should be very careful of what they put down their drains.

Pic 24 has a lot of slope, maybe too much, in my opinion. The reason I say that is while plumbing code min is 1/4"/foot, too much slope may not allow solids to be washed along the drain as the liquid rushes by too quickly to carry the solids. Still what you've done is not the end of the world, my comments are for future reference and for others who may read this thread.

Pic 25 was there no way to push the pipe through by enlarging the holes slightly? Or installing it in smaller sections? Admittedly I'm no expert in structural matters but I avoid notching joists that way at all costs as I would worry about the integrity of those studs. I realize it's only 2 studs but I'm a worrier by nature.

Pic 26 good idea with the deflector plates. After all the work you'd done it would be Murphy's Law paying a visit if you if hadn't.

Pic 29 looks like nice finish. No one will even know all the work you put in, except for all the photographic evidence.

Andy.

TheEplumber 08-23-2011 12:06 AM

Nice work Pete :thumbsup:

PeteW 08-23-2011 12:09 PM

I'm still planning on testing the drain lines before I finish reinstalling the sinks. I plan to use a hose and let water run through both the washing machine drain and the kitchen drain for about 15 minutes and look for water water to seep out from the bottom of the wall. If I do fins that there is a leak, then I'll just redo it. It was dumb to get get ahead of myself, but I will make sure it's right before I move on.

I have no idea if this is a good way to do this. Any suggestions?


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