drains for new bathroom

[Bravloue]

I have an older home and plan to add a bathroom where there is a large utility room. There is a 3†drain through the wall with a trap outside the room (freezing is not a problem in this part of Florida). The utility room is on a concrete floor about 6†below the rest of the house. My goal is to run all the drains on the existing floor and pore concrete in the room and bring the floor to the same elevation as the rest of the house

My question is in regard to the trap for the shower and toilet. If I place the shower drain within 3 feet of the existing outside trap, do I need to put a trap directly under the shower or can I just 90 over the existing trap?

Should I run the toilet drain before or after the existing trap. I assume I can just 90 over from the toilet to the drain?

Lastly, what is the furthest away the vent can be from the toilet drain, can I tie vents together?

Thanks in advance for your help.

Lou

 

[Jadnashua]

You want a trap under the shower, not 5' away, otherwise, you'd have 5' of pipe with soap scum, hair, body oils, etc. festering in the line - the trap blocks the smells from that as well as the sewer. The distance you can be from a vent (you mentioned trap - EACH drain needs a vent AND a trap - well, a toilet has a trap built-into it). Vents can be combined so you don't need to run individual pipes up through the roof. That is done around 6" above the flood plane of the highest one - people often pick 42", as that would account for a kitchen counter's sink height. The distance from the vent depends on the diameter of the drain line. I think (don't quote me) on a 3" line, it is 5'. It gets shorter with smaller drains.

Keep in mind, all drains need to slope down at 1/4" per foot, too, so depending on where you place things, you may still have to break some concrete.

 

[Sponsor]

 

[Geniescience]

You're lucky you have 6" as that's enough room to put traps everywhere and even have a floor drain (and trap) too. That means the single outdoor trap is going to be removed, disappeared. Individual traps for each fixture except toilets. This means sinks, tubs, showers, floor drains, washers, urinals, etc.

Besides, you would need to run a separate arm for the toilet anyway since a toilet takes a non-trapped arm; toilets have their trap built in, inside the toilet bowl. Never have two traps in series. So since you need more pipe for the toilet anyway even if you were to keep the idea of one big single trap for everything, it is just as easy and a lot better to put a trap under each drain hole. One for the sink, one for the shower, one for the floor drain, etc.

Before planning this layout, you have to figure out where you are going to send your vent pipes down. The drain pipes go to the vent first and then get directed to the outdoors; where to combine them is the last decision to make. So it's trap, then vent, then down and out. If you had one fewer vent than the number of fixtures it might also work well depending on the layout, with vents at pipe connection nodes, but my saying this is not a recommendation for you to plan it this way at the outset.

david

 

[Bravloue]

Bathroom drains

Thanks for both pieces of advice. The one time I worked on a shower drain the trap was about 12" beneath the concrete. If I understand you guys correctly, I can squeeze a trap and drain line in only 6" of space? If this is the case I this will be an easy job. Truth is, the existing floor tapers down, I actually have more than 6" space.

Thanks
Lou

 

[Jadnashua]

A 2" shower trap might need a little more than 6", but not much. The top of the trap can be right at the drain, plus whatever you need to make the connection.

 

[Geniescience]

yeah, give or take, plus or minus, almost, good enough, you'll figure out what to do to make it fit. First off, you can raise the shower floor a bit, or notch groove a little spot in the slab to make a space for the p trap, or a bit of both, if need be. I have even cut copper elbows down to make them fit into tight spaces; there is a huge amount of surface area given to you when you solder the whole elbow as is, so cutting off 40% of the sleeve part just to make it smaller works for me. I did that to "street elbows" - they are the ones that have one end female, and one end male, so they take less space to begin with than regular elbows (female-female) but I still had to shave them down to fit a tight space. I suppose a bit of cutting down to size would work with PVC parts too.

david