plumbing plans comments

Greetings;

I am DIY building a small slab on grade (frost footings) cabin. I am looking for a critique of my under slab plumbing plans, please see attached. Any red flags, tips/tricks or suggestions are greatly appreciated.

Thanks for your help:

Perry Clark

dwv

No problem with the drawing. The problems, if any, will be in the execution, because we do not know exactly HOW you will install the piping. Almost ALL critical items, and errors, occur in the vertical piping which your drawing does not show.

Thanks:

Your right, I fully understand about the execution. I am mostly concerned with the under slab work because it is impossible to change, and it is my most immediate need. A couple specific questions:

1) Is the placement of the main vent through the roof optimal?
2) Compaction of trenches after laying the pipe (our lot is pure sand), is just hand tamping enough?

Thanks:

Perry

Are there enough vents here? When you flush the toilet would it not suck water out of the p trap in the bath sink?

Thanks:

I plan on venting all of the fixtures through interior walls up into the attic trusses and then tie into the main vent stack. I am not really showing that I am just looking at the plumbing below the slab, since this has to be done soon.

Thanks:

Perry

Pclark said:

Thanks:

I plan on venting all of the fixtures through interior walls up into the attic trusses and then tie into the main vent stack. I am not really showing that I am just looking at the plumbing below the slab, since this has to be done soon.

Thanks:

Perry

Click to expand...

The vents for fixtures that rough-in below grade (toilet, tub, water softener?) need the vents taken off before you pour the slab.

Thanks:

I was planning on framing a box around the tub plumbing so it does not get poured into the concrete. The softener I was just planning on making a stand pipe like for a wash machine and put the trap above the slab. I am a little confused about the toilet; do you think it needs its own vent? Is having the 3" main stack not enough or is the main stack in the wrong location?

Thanks:

Perry

Pclark said:

.....
2) Compaction of trenches after laying the pipe (our lot is pure sand), is just hand tamping enough?
....

Click to expand...

Hand compaction can be adequate if you put enough effort into it. Uness the area is small you're better off renting a trench tamper.

Either way, moisture content is alway critical. If you can squeeze water out of a handful then its too wet. If you have dust forming then its too dry. You should be able to walk on the compacted trenches no differently then the undisturbed areas when you're done.

In critical areas (like crossing wall footings) I'd recomend using a Collins Ax to compact. This is a heavy steel bar with a mushroom shaped head on one end about 3" in diameter. (The other end is a sharp chisel, used to cut roots in a hole.) Anything larger and lighter just can't put enough energy to the soil.