Installing Bathroom in Basement Need Advice

Jeffrey262

Hello,

I am building a full bathroom in my basement. I have completed the framing. Rough plumbing was completed when the house was built. I installed a peatrap for the shower. I am using a shower basin.

I have 3 other pvc pipes coming up from the basement floor. One waste for the toliet and two vents. I assume one vent is for the sink and the other for the shower.

I am confused on how to vent the sink. If I use 1 1/2" pvc for the sink waste, do I tie the sink waste into the vent pvc with a Sanitary tee? Can I tie both vent pipes together and run them up to the above bathroom vent pipe?

I am going to run the cooper as well. I see there is 3/4" pipe running out the main branch. Do I continue to run 3/4" pipe all the way to the sink, shower, and toliet -- then come down with 1/2" pipe to the shower, toliet, and sink? Also, does it matter where I add the shock absorbers at each fixture?

Is there anything else I should know? I appreciate your advice?

By the way, I live in the Chicagoland area just in case you needed to know.

al's sewer

Usually on a 3 piece bath rough in the basement you should have 3 pipes coming out. A 4 inch pipe for the toilet a 2 inch pipe for the lavi drain and vent and a 2 inch for the shower drain which should already have a p-trap in it(if you are putting a tub in you would reduce this one to 11/2inch just above the p-trap. Usually the lavi drain acts as a vent for the whole bathroom depending on how far apart the fixtures are. You want to keep it 2 inch all the way to the main stack or thru the roof whichever is easiest. When you tie your vent in make sure that you are 6 to 8 iches above the flood rim of the highest fixture. If you hada rough in the basement check to see if they dropped a future vent into the basement and capped it off. I always did that but most plumbers don't unless required by code. To tie into the stack you can use a sanitary tee turned upside down to allow the flow of air to rise upwards easier.
As far as the water line goes I usually don't catch more than 3 fixtures on a 1/2 inch line(some codes allow for 6 or 7 on a 1/2 inch line). For example I would run 3/4 inch to the toilet on the cold then reduce to 1/2 inch to catch the shower and vanity and on the hot I would tie into a 3/4 inch line and run 1/2 to both lavi and shower. If you want more volume You can run 3/4 all the way to each fixture but I find that unnecessary unless you have very low water pressure and even then it doesn't help much.
The shock absorbers should be behind the wall as close to each fixture as possible.

JDC

The water hammer arrestors (shock absorbers) are usually installed on fixtures with quick closing valves (ie selanoid valves) such as washing machine box, dishwasher, etc. Using them in the bathroom wont hurt though. I'd just put in one set on the shower with an access panel and ball valves for changing them out when the time comes.

As far as the pipes coming out of the floor...
One for the toilet, 3 or 4 inch
One for the shower vent most likely
One for the lavatory drain. You cut this off at the proper elevation, install a sanitary tee for your fixture arm going to your vanity, then the vent comes out of the top of the tee. As Al stated, be sure you are at least 6 inches above the highest fixture served before tying your vents together. Run the vent up to an existing vent and tie it in or run it out the roof on its own. Check to see what size your vent must be at the roof penetration if you are running it out on its own. In Ohio it has to be at least 3" due to frost considerations so...if the vent in the house is smaller it must increase in size 6" before it exits the structure.

Jeffrey262

Al,
Thank you for the information. As far as the rough in, here is what I have:
1) One 4" pipe for the Toliet
2) Two 2" pipe -- I thought both of these were vents
3) One 3", 3 1/2", or 4" pipe for the shower drain.

I attached a few pictures of the rough in.

I also attached a picture of a vent pipe above or very close to the location of the new bathroom. I assume I can tie al the vents into this pipe.

Do you think both of those 2" pipes are vents? If they are, what do you recommend I do for a drain?

There is an ejector pump already in place. If you want I can go take a picture of the bathroom frame to show you where the elector pump is located.

Thank you

Attached Images

   

al's sewer

Ok it looks like they drop a future vent for you all you have to do is tie all you vents into that pipe. the 2 2 inch lines are probably your lavi waste and a releif vent on the toilet just tie them together after you put you tee in for your lavi waste and hook up to that pipe with a cap on the end of it. Your sewer ejector should have a separate vent of its own going through the roof. your shower drain only has to be 2 inch also. if your ejector pit is not vented thru the roof on its own go ahead and tie it into the vent system for the basement bath not exactly up to code but oh well

Jeffrey262

Al, Thanks.

How do I know which 2" pipe is the vent and which is for the sink waste?

--jeff

al's sewer

The one on the right is the furthest from toilet rough in so I would say it would be that one, but if that is on the wrong side just use the other one the toilet will still vent so basically either one can be used If I was doing it I would use the one on the right if at all possible.