No Walls for Plumbing!

Hello,

Here is a link to images.
http://imgur.com/a/GQ8Bd

I am a slightly handy young man with limited plumbing experience building a dry stack house on an extremely tight budget, [I'm a teacher]. It is loft style, so really tiny, about a thousand square feet. I am struggling to find all of the answers I need because i will not be running piping in the walls.

http://imgur.com/a/GQ8Bd shows an image of the drain system I have planned. The trenches are the footings. Will this work? I understand the slope issue, I am asking about the layout.

I am getting mixed information about the size to use for the drains. 1 1/2" for sinks? 2" for showers and tubs? What about toilet?

Where do i have to have Clean outs?


ok, on to venting.

Since I have to come up six inches about the highest point of the fixture and I can't put them in the walls i was hoping i could just run them to the top of the room exposed inside and meet them up and then vent outside. I am hopelessly lost on wet venting horizontal venting so I pretty much vented everything independently, not sure if all of that is needed. I understand i need to vent them within so many feet of the trap. Will this system for venting work? Will it pass inspection? The office is not being helpful.


ok, on to supply.

I am hoping to run PEX line below the concrete, red blue to each fixture. Because i have drain lines running everywhere planning supply lines seems to be a nightmare. I have to be one foot above them when i cross them so i guess this means i just need to put my drain lines really deep? I have heard mixed issues with running the line in protective piping. I was planning on only using sleeves when crossing a drain line and when penetrating the concrete. Can i just run the lines 4 inches or so below the slab while one foot about the drain pipes and backfill over them with sand?

Again, i am not sure on what the best size supply lines for the different fixtures should be.


Since the whole set up is a touch unusual, where do i have to have clean outs?

I appreciate any advice you can offer me, even if you cannot answer everything.

I appreciate your time,
Nicholas Miller

Toilet is 3" minimum. You can wet vent the bathroom group, but that can NOT include the washer or kitchen. There are issues about just venting "outside". Can 't be near windows or doors. Ideally, would vent thru the roof. There are details about what types of fittings must be used where, which will kill you! The building department will probably not issue a permit based on the diagram you have. More detail needed.

So you want to undermine existing footings?

Unless you like the industrial look, I would frame stud walls inside the existing structure. All the fixture drains should be 2", and the water closet 3".

Without knowing what you are starting with, it's hard to advise. If I were cutting a trench across the center of my house, I would shoot for the shortest and straightest run possible.

I "LOVE" it when someone designs a building that you CANNOT install plumbing and electrical in it. I worked on a U.S. Steel house years ago. They delivered and assembled it in a couple of days and you could move right in. The only problem was they made minimal provision for installing the plumbing, electrical, and heating. Other than that, the house looked "great".

If you have solid walls, then the plumbing goes on the outside of those walls.
It's the same problem that log cabins have too.

Most homes have wiring, plumbing, insulation, cable, vapor barrier, fans and venting.
If you don't want to install them in the wall, then you have to attach or apply them to the outside of the wall.

The plumbing fixtures will need vents.
The shower within five feet, the lav within 42"
The toilet vent, as it is drawn, can't be used to vent anything else there. You will need other vents going through the roof.
The washer will need a vent, and the kitchen sink.

I have built dry stacks, granted with double cores, one for steel and one for insulation. 16x16x8 as I recall. Ran threaded rods to the top and pretensioned them before grouting. There was room for some pipe IN the wall, and your design needs to get rid of all the interior dry stacks.

THAT is your design flaw. Dry stacks are for exterior walls. frame the interior and now plumb to your hearts content - and have some shear when the earthquake hits. BOLT thru the blocks into your wood shear walls. Got free blocks? Use them for the shed.

Dont forget the radiant floor!

I am designing a house built of those compressed bails of cardboard. Make a straw bale look like a bad joke. Problem is if they get wet, your house is suddenly a few feet wider.

quote; Problem is if they get wet, your house is suddenly a few feet wider.

AND the ceilings are lower.

I think it would grow in height also.