Elevate bathroom in garage or not?

[Reitwagen]

So I'm getting ready to pour my shop floor and I'm torn on a few things. One is the bathroom/mechanical room.

Do I keep it at slab level and run the waste lines under the concrete or do I just stub the main line up and frame the bathroom floor with conventional lumber and run my waste lines thru that.

The room will be 10x12 and have a stall shower, slop sink, toilet and a washer/dryer hookup there isn't a ton of waste plumbing but there is a bit of it.

The back wall will have the furnace for the radiant heat, manifolds, expansion tank etc...

There will be 11 feet from finished height of concrete to the ceiling so there is plenty or room to raise the bathroom floor a foot or two.

Raising it seems more forgiving if I make a plumbing mistake.

Anyone have any thoughts or insight they woud like to share? Is there something I'm not realizing?

 

[Onewolf]

We are leaving the full bathroom floor at the garage floor elevation and running the sewer/freshwater lines under the slab. The air conditioned carpeted workshop/hobby room slab floor is elevated 4". We left the bathroom floor at garage floor elevation in case there's a plumbing issue it won't 'ruin' the finished/nice areas.

 

[wnstwolf]

Unless your absolutly sure where fixtures will go it is tough to put it under the slab. I did this in my basement for a future bathroom but left 2x2' open space with no concrete just the pipes in the ground poppoing up in the center of the box out. Gives a little wiggle room when I go back to finish and a quick bag or 2 of mix will finish it off.. Easier than cutting concrete. Most toilets are standard offset for how far off the back wall the drain is. The problem I worried about was the shower. they are all different..

 

[Tronyadorable]

Leave it level. The next owner might want to turn the garage into a room. I'll never have an attached garage again. No way.

 

[8man]

Leave it level. The block out as described by wnstwolf is one way to make sure it is where you want it. Then when you actually locate the toilet or shower drain you can concrete it in.

 

[Wylaco]

Most of the time it is left the same level. Get your rough in's right and it will not be an issue. Also think about water lines, if you are in an area that will freeze run the water lines underground, you do not want them in exterior walls or attic space!

If you are running a standard toilet, the drain center needs to be 12-13" off back wall and 15.5" at least off side walls. Lav drains just center on the drain location of sink. Box out your shower drain with wood and don't pour there, the shower will actually sit lower than the concrete if that makes sense.

edit: your toilet needs to be 15" off finished wall, so depending on what you use it may need to be further than 15.5:

 

[HoosierMark]

You really only have one critical main line that needs to be in the floor. That is the toilet. The other lines can all be plumbed in a 2 x 6 wall with only one line coming up for the others to connect to. Even the shower can be raised if you so desire, since you could easily step up into the shower. My plumber typically puts in the rough plumbing under the slab for a shower/tub and then puts a piece of heavy stryofoam over the area the pipes will come thru the floor in. They pour a 1 inch +/- thick concrete over the whole area of the foam (as they pour the whole slab). Then all he needs to do is remove the thinner concrete and connect the tub area. For the toilet flange he puts it in the floor in the right place and duct tapes it all to keep it clean from the concrete mess.

 

[Leaflessshadetree]

Put the drains in the right place and you only rough it in once. How many times will you be stepping up into the room and down out of the room?

One idea I did consider was to have a wood floor and "crawl space" under the bathroom but I'd keep it level with the garage floor.

 

[wssix99]

If you are going to have gas powered equipment in the shop, you should raise it and build a has curb for safety reasons. You'd then have a ton of options for the floor and utilities.

 

[NUTTSGT]

Put the drains in the right place and you only rough it in once. How many times will you be stepping up into the room and down out of the room?

One idea I did consider was to have a wood floor and "crawl space" under the bathroom but I'd keep it level with the garage floor.

Since my garage was an old gas station, it has two different levels, the bathroom being a step up on wood floor. While it did make it handy to do some replumbing, if I built new, I'd have it all one level.

The only possiblility that might change it for me is if I put a small basement area under and office/bathroom.