New plumbing in old structure


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Old 01-21-20, 07:10 AM
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New plumbing in old structure

Hello,
I am converting a barn into a 2 bedroom 2 bathroom home. Previously the plumbing was run on top the concrete and out the wall to be hooked into the septic tank. I have gutted the building completely and with permits will be legally converting this dwelling. I am trying to figure out the best way to run the plumbing under the concrete. I attached a floor plan with black lines where I am thinking of running the plumbing. Is this the best way to run it? Or should I have less 90 degree bends?
 
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Old 01-21-20, 09:24 AM
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I think in terms of pipe size. Large pipes are more difficult to run so I plan them out first. In your case the line from the toilet is largest so I'd route the line right under the toilet or very nearby. The tub and sink are much smaller and easier to run so they can easily be routed over to the 3" or 4" main.
 
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Old 01-21-20, 10:21 AM
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Here's another way I was thinking to run it. There is nothing in the way right now to cut the concrete except for the walls between the stairs. If I went with this layout I may have a hard time going under those walls for the stairs.
 
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Old 01-21-20, 10:43 AM
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I only offer this as comment since I'm not a plumber and this is beyond my "pay rate". But don't you want to eliminate any all 90 degree ells? It seems your alternative diagram makes more sense in terms of flow. And you may want to extend the sinks on an angle.
 
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Old 01-21-20, 11:09 AM
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Or should I have less 90 degree bends?
I would avoid 90 degree fittings and make my 90s with two 45s or a Y fitting with a 45. Remember, sanitary tees cannot be installed on their side.
 
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Old 01-21-20, 12:55 PM
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Also, the 6" wall on either side of the stairway is between 6x6 load bearing posts. I do not think these walls are load bearing, but certainly the posts. Can I dig under and place plumbing under such a wall?
 
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Old 01-21-20, 01:08 PM
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I would route the piping around the existing walls, especially if there may be footers in the area. If you are concerned about 90° fittings you can use sweep elbows or two 45° fittings for a more gradual radius. But, 90's are commonly used without problem so using them aren't the end of the world. Using sweeps or a pair of 45's does make it easier to snake the line if there ever is a clog.
 
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Old 01-21-20, 06:16 PM
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This was my first thought on how to run it.

Your toilet, vanity sink, laundry, and kitchen sink will need vents through the roof (or could be back-vented all into the toilet vent if there's an attic. Any clogs could be easily snaked from the toilet or kitchen sink.

Make sure you add a cleanout in the front yard, though with a straight shot like that, I don't anticipate any clogs anytime soon.
 
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Old 01-22-20, 07:19 PM
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Your digging in too deep with the ground layout without first considering the venting of fixtures.

When fixtures are on oppisite sides of main run ,vents will need to be run up walls.

The showe should really dump into the lav arm, and the laundry gets vented on its on along with the kitchen.

And I would dump the laundry with vent into the kitchen arm to keep kitchen line clear of grease..
 
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Old 01-23-20, 02:38 AM
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If you are installing a dishwasher that will help keep the kitchen drain free of grease,
 
 

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