New Shower

[techguy]

I am thinking about putting a shower stall in a half/bathroom I have. My house is on a slab with radient heat so I can't cut into the concrete. The only place I have room for a stall would be over the main sewer line that goes out of the house. There is a hole in the concrete that exposes the line with the vent that goes outside. Next to the vent is the drain trap. The vent line is about 3 inches so I was thinking about using a tee off the main line (vent opening)for an addl shower drain and vent. The problem is that once it is done I wont have access to this area anymore. My thought was that if I ever had to snake out the line I could take the adject toilet off (about 5 feet away) and use that?? Any thoughts?

[LazyPup]

I have read this post about twenty times and I am still a bit confused. If I am understanding this correctly, the opening in the concrete is over the building main drain where it exits the building to meet the building sewer line to the municipal sewer or septic tank.

There are two points that I find confusing:

1. The post says the vent also runs through the wall to the outside. A vent must run vertical up and out through the roof. It may not be run outside the building.

2. What is the purpose of the trap mentioned in the post? In years past it was a requirement to install a house main trap on the main drain line at or near the foundation wall, but house traps have been outlawed for a number of years.

The code requires a main cleanout be installed within three feet of the foundation wall at the point were the main sewer attaches to the house main drain. On basement construction it is installed immeciately inside the basement. On slab construction it is installed 3 feet outside the foundation wall.

You can install a tee on the main cleanout to make a new connection providing the end of the tee is fitted with a cleanout cap to afford rodding, but if you do so, you must maintain a minimum of 24 inches assured clearance at the cleanout for rodding the line.

In this case the toilet may not be used as the cleanout because the toilet is on the end of a waste arm, and you could only rod the line downstream in the direction of the street or septic tank sewer connection. The main cleanout must be a rodding tee fitting to permit rodding both the house main drain upstream and the house sewer downstream from that point.

Since this house is on slab construction, you could elect to dig down to the line outside the foundation wall and install an outside main cleanout, then you could use the existing cleanout as an access for the shower waste arm.

To make the outside cleanout, dig down to the line, install a Rodding Tee and make a veritcal riser up to grede level with a cleanout cap on the top.

[techguy]

Thanks for the quick response. After reading it again it does sound a bit confusing. Here is what I have. The previous owners put an extension on the house. By doing that they brought the exterior waste trap/cleanout inside. They did leave a hole in the concrete (house is on a slab) for access. There is a vent on the cleanout fitting as well. The vent runs along the interior wall and goes outside. This vent is in addition to the one on the roof. My question was can I use this vent (with a tee) for my shower drain? If I elect to add an additional cleanout trap outside how far from the house can it be? I have a deck outside so it couldn't be right next to the house. The tricky part is that the shower is going to go over the hole in the floor that contains the trap/cleanout. I was thinking of rasing the floor a bit so you would still have access to the cleanout.

[LazyPup]

The solution to you problem is rather simple. First, there should not ba a trap on the main drain line, so if there is one you should remove it.

The vent is also not connected properly, but the good news is, there is no need to have a vent there anyway, so you can also remove that.

You can attach your shower drain at the existing cleanout location, providing you install a new main cleanout outside the building. I have attached a drawing to show the proper location of the new cleanout, and the layout for your shower drain line.

The code requires a shower drain to be a 2" line & Trap.

The code prohibits installing slip joint traps in a concealed location so you will have to install a glue in type P-trap.

The code requires a horizontal waste arm with a minimum length of two times the trap diameter, so you will have to make it a minimum of 4 inches. Maximum 8 ft.



When you cut into the main drain line to conect the rodding tee you can use a PVC coupling to connect the pipe on the downstream end and use a "FERNCO" rubber coupling on the other end.

[techguy]

I am attaching an image of the existing trap/vent. The vent is the white pvc pipe on the left. The house side of the trap is on the left and the street side is on the right. Don't you need a trap and vent on the main line to prevent sewer gas from getting into the house? This plumbing should be original to the house (built in the 50's). If I added a rodding tee with a riser outside of the house how would you direct the rod up or down stream. It looks like the rod would hit the bottom of the tee and stop (how rigid is a rod?) If it could make the bend wouldn't it just be random as to which direction it went? If you were at the rodding tee you can push it up or down stream. Another thought, how far can this rodding tee be from the house? Is 17 feet too far? Thank you very much for all of this help!

[LazyPup]

Back in the days when your house was built the municipal sewers were also the city storm drains and often it was all dumped directly into local streams. When cities began building municipal sewage treatment plants it was realized that the storm drainage was overloading the treatment plants so they decided to run separate sewer lines for sewage and storm drainage. When the storm drains were attached to the sewers the storm grates also served as vents for the sewer system. When the storm drains were separated from the sewers they ran into a tremendious problem of Methane gas being trapped in the sewers. Many sewer workers were asphyxiated and in some instances the buildup of methane was so great that sewers actually blew up. In some cses the explosions were strong enough to level entire city blocks.

The plumbing codes were revised to prohibit the main house trap.

When a house is tapped into the municipal sewer, a house sewer line is run from the street to the house main cleanout. The line then continues undiminished in size under the house to form the main building drain. At any point along the main building drain a line is then run up and out through the roof, again, undiminished in size. In this manner the main vent is not only the main vent for your structure but it also serves to provide a portion of the vent for the municipal sewer lines. By insuring that each house or structure has a main vent they can also insure that the proportion of vent on the municipal sewer is adequate for the load in any given area.

Years ago drains were cleaned by running 1/2 inch diameter steel rods through the pipes, thus the term "Rodding". Although that method is no longer used to clean drains the process of mechanically cleaning a drain is still properly called "Rodding the line."

Drains are now cleaned by means of mechanical drain snakes which use flexible steel cables to turn the cutters used to clean the lines. There are many variations of drain snakes from the common 1/4 wire snake which is little more than a 15 or 25 foot long screen door spring, to powered augers that have a 1/2inch diameter cable with cutters up to 6 inches. Many municipal sewer companies have truck mounted cable snakes that have a 1 inch diameter cable capable of cleaning up to 24 inch diameter lines.

An oridnary sanitary tee has a radius bend to direct the flow in the downstream direction. A Rodding tee has a radius bend in both directions so the cable can be directed to go either upstream or downstream. Drain cleaning companies have a short length of angle iron with a curve formed on one end. The Iron is put down the cleanout and the cable is then fed in. As the end of the cable reaches the bend on the end of the iron, the cable is bent to direct the cable in the desired direction. Once the cable is started into the pipe, the angle iron is pulled out and the machine is started to twist the cable and cutters as it is fed into the pipe.

A Rodding Tee is the only tee fitting that may be installed with the tee side opening in the vertical position.

When a vertical vent or sewer line is connected to a horizontal line it must be connected by means of a Sanitary Wye & 1/8th bend or a Combo. (A combo is a one piece fitting that is the same size as a Wye and a Street 1/8th bend.)

[techguy]

I see. Is it bad to have the trap in the house? I'm wondering why it was not removed if it is dangerous? In you drawing above, the shower drain does not need a vent?

[LazyPup]

Given the short distance of the run from the main drain to the shower base, the shower will be wet vented.

Although the house trap does isolate your house from the municipal sewer it is not dangerous because there are other buildings connected to the sewer that supply vents to it, and you house has a main vent that would vent off dangerous gasses that develope on you side of the house trap.

Technically speaking, according to code the house trap should be removed for two reasons. 1. House traps are prohibited, and 2. It is a violation of code to put two traps in succession to each other. In this case the house trap is in succession to all the traps in the structure.

Another major consideration here is that if you allow the house trap to remain, you must provide immediate access to it to clean it, which is why the opening was left in the floor. The simple solution would be to remove the trap, install your shower waste arm, then fill the hole.

[techguy]

I went to a local Home Depot and picked up a 4" rodding tee. They did not have a 3" but 4" would probably be easier to rod anyway. I started to talk to a guy who works there about what I was doing and he said that I have to have a trap on the main. Could the code be different in my town from where you are from?

[LazyPup]

I just reviewed my drawing and it may be a bit misleading. In your original post you stated the vent line was 3" and given that 3" is the minimum size for a house main drain or house sewer line I labeled the drawing at 3", but it may be a 4" line. You will have to determine the actual size of your line, then install fittings to match your line. You may not change the diameter of any fittings on that line.

In regards to the house trap. House traps were outlawed in all codes nearly 20 yrs ago. Perhaps your just discovered why that guy is working at Home Depot instead of working in the Plumbing trade, but for the sake of argument, it is possible that you have a local code variation. The solution would be to call your local Code inspector or zoning commission office and ask them what your local codes demand.

[techguy]

I called the town plumbing inspector today and he said that I need a trap/cleanout and vent on the main line. I guess the codes can vary by that much from state to state. His reason was that if a trap on a sink (for example) dried out then you could/would get sewer gas in the house. Thank you very much for all of your help!

[LazyPup]

Wow,,I find it amazing that your local code still requires a house trap. The International Residential Code, Uniform Plumbing Code, BOCA Plumbing Code and SBCCA plumbing codes all prohibit them.

In my jurisdiction we have an ordinance that says when we encounter a house trap we are required to remove it immediately or notify the code enforcement office in writing within 24 hours. In addition, when we remove a house trap we are required to break it in a minimum of three pieces to insure it can not be used again.

We are also subject to a $500 per unit fine for any servicable house traps in our inventories.

[techguy]

I guess the zoning laws vary from state to state. Can I ask what state you are from? I'm from New York.

[LazyPup]

I am curently working in Ohio & Pa and am applying for licensing in western N.Y. .have also recently worked in Florida, Alabama, Mississippi and Texas.

If you are in New York you may need to ask your code officer if you can perform any DIY service. The trade publications are saying that all plumbing work in New York whatsoever MUST BE performed by licensed plumbers.

[techguy]

The plumbing inspector knows I am doing it. He even asked if I wanted him to come by to give me some pointers. I got the stuff today so I may tackle it tomorrow?