Ask Me Help Desk - Drum trap question

My upstairs shower drain has been running more and more slowly over the past few months. We tried chemicals and snaking it, to no avail. I finally called a plumber last week. He opened the crawlspace and pointed out the drum trap, and said that it was likely a clog in the drum trap. He said that he didn't work on drum traps because they do not meet current codes (my home was built in 1928). He also said that "some people might open it up and shop-vac it out." He then proceeded to explain that he would need to remove the drum trap, open an access hole in my kitchen ceiling, put in a P-trap, etc. He said that if that didn't solve the problem, he would snake it. The estimate was approximately $1,000. Yikes!

Taking the tip from the plumber, my husband and I opened up the drum trap this weekend, vacuumed it out, and snaked it both toward the shower drain and to the main drain (but I'm not sure how far).

The problem: the shower is no faster AND now the bathroom sink is backing up into the shower drain.

So, a few questions - why is the sink now backing up? If the drum trap has been cleaned out and this hasn't solved the problem, does it really need to be removed? What are my options for cheap solutions? Cleaning the drum trap pretty much reached the limit of our DYI abilities!

Thanks so much for any and all help!

Hi Crissy,

"I finally called a plumber last week. He opened the crawlspace and pointed out the drum trap, and said that it was likely a clog in the drum trap. He said that he didn't work on drum traps because they do not meet current codes (my home was built in 1928). He also said that "some people might open it up and shop-vac it out." He then proceeded to explain that he would need to remove the drum trap, open an access hole in my kitchen ceiling, put in a P-trap, etc. He said that if that didn't solve the problem, he would snake it. The estimate was approximately $1,000. Yikes!"

And "double yikes!!" I think your plumber was blowing smoke! While drum traps may be outlawed by your local codes from new installations there is nothing in the code book that would prevent him from snaking out a existing one. He must have known that cleaning out the trap wouldn't unclog a blockage farther on down the line. If anyone else gives you a hard time about a drum trap just refer them to Chapter 7, Section 702.4(a) of the Standard Plumbing code.

Now, on to your problem. You've cleaned out the gunk from the trap. Good!
The tub is wet vented by the lavatory vent. That means it's connected to the lavatory drain.
When you snaked the tub drain line you pushed the clog out into the lavatory drain line.
All you have to do is rent a longer power snake and you can snake through the drum trap or come down the lavatory roof vent. You're halfway home and just think of the weekend you can have with that thousand bucks you've saved. Cheers, tom

First off, I'd like to point out that I am a plumber. I assume the drum trap you are talking about has a clean out cap on top accessible from the floor directly above it. Drum traps, especially in old buildings, are particularly pesky. The cap tends to corrode to the trap making it difficult to remove, then if you wrench down on it it is likely to damage the threads on the cap or to even tweak something else down the line causing even more problems. I can see him not wanting to deal with that, so in his experience removing it had a higher probability of success.

You however were able to remove the cap, so good on you. The problems that happened next was probably from snaking it. The "clog" that existed is usually a thick paste of soap, hair and dead skin that looks like a muddy gel, going the length of the pipe until it reaches the building drain. When it is draining, there is a,small tunnel that goes through the gunk, and the draining water takes that path. In your case, the line was probably 1 1/2" emptying into a 3" or 4" building drain. If you're not certain to go all the way through the small pipe with the snake and into the big pipe, then you pretty much dam up the small hole that your water is flowing through and make it back up even more. The reason your sink draining causes the tub to have water rise in it is because by not snaking all the way through the line, a full enclosure of the pipe was caused AFTER the sink. With the tub being the low point, water naturally "drained" into the tub.

The best thing to do is to remove the old drum trap AND pipe, almost up to where it empties into the bigger line and replace it with plastic. Save a few inches of the old line to connect in the new pipe with a flexible (or no hub) coupling, but snake those few inches with a hand snake to open it up and well into the bigger pipe before putting in the length of plastic pipe. Plastic is so much better because it is smooth and gunk doesn't build up in it.

Hi Mike and welcome to The Plumbing Page at AskMeHelpDesk.com You are responding to a 6 year old dead thread so Please check the date before you post. Thanks,
That was a great post and your solution,

Quote:

The best thing to do is to remove the old drum trap AND pipe, almost up to where it empties into the bigger line and replace it with plastic.

was bang on. However,
That's not how we do things on The Plumbing Page.
Our askers are do it yourselfers that are looking for the easiest, less expensive way to solve their problem and while tearing up the bathroom and replacing the entire line from tub to stack may be plumbing correct but that's not what they want to hear. They want to know what they can do to fix it themselves.
Now that you know what we're about you strike me that you know your stuff and would be a great addition to our group. We are a tight group of plumbers from all codes that try to pass some of our experiences on to others. Please consider joining us. Regards. Tom