Building Drain through foundation wall or under footing?

[Steven Whitehead]

Hi,
I'm a plumbing newbie/DIYer and I could use some help. I'm designing a small house for my Dad in Idaho and I'm trying to sort of the plumbing details. The house will be placed on a gradual hillside, has a full (walk-out) basement, a main floor and an liveable attic. From a plumbing perspective, it has two baths (1 main floor, 1 attic), a laundry room, a kitchen, and a basement utility sink. My current plumbing riser diagram is attached. The DWV system will drain to a private septic system.

Here is my main question:
1) Should the building drain exit the house through the basement foundation wall (concrete) or through the basement floor/slab and under the foundation footing (also concrete)? In either case, I'd plan to use a sleeve to protect the drain pipe, as required by code. Also, as of now, I have no plans to put a toilet (or other plumbing fixtures) in the basement, aside from the one utility sink.

Related questions:
2) What are the factors that I should consider when making this decision?
Note: Because I'm on a hill and my groundwater is sufficiently low, the placement (depth) of the septic
system can accommodate either approach (or so I think).

3) If I end up routing the building drain through the foundation wall, I'll likely have to relocate the drain further to the left compared to where it is shown in the diagram. I'd do this in order to keep the drain below the frost line, given that the house is situated on a hillside. In this case, I'll have two 3" horizontal drain lines (one coming from the left, one from the right) converging on the building drain. What is the best method for joining these two lines at the building drain?

And finally,
4) What about other penetrations? In particular, our water supply will come from a private well. We'll also have gas (propane) and electrical (solar) feeding into the basement. What do folks recommend for these penetrations? My current thinking is to bring these things in through the foundation walls with sleeved penetrations.

I appreciate any advice, insight you can offer.
Many thanks!
-Steve

 

[Steven Whitehead]

In case you can't read the attached *.jpg file, here is a *.png. This should be clearer. Thanks,

 

[Sponsor]

 

[Jeff H Young]

Id bring it through floor and put a floor drain in. the other utilitys through sleeve in wall.

 

[Steven Whitehead]

Thanks Jeff. I had thought about adding a floor drain, but have hesitated, since this is a vacation home and I worry about a basement drain's P-trap drying out and stinking up the place, especially during those long winter months when the place might be vacant. For simplicity I didn't want to add a 'trap primer' to keep a basement floor drain's trap full. (Again, off-gridish house w/ limited electric during winter months etc). I suppose I could add a 'vapour block' product (like "Brodi vapour block") or perhaps RV antifreeze (?) to help prevent the a basement drain trap from drying out during long periods of absense... But instead, since I don't have any known need for a basement floor drain (though it'd be nice), I've been leaning towards going without one. Besides a floor drain, are there other reasons you'd go through the floor?
Thanks!

 

[Reach4]

Besides a floor drain, are there other reasons you'd go through the floor?

Laundry sink, or laundry standpipe in the basement. Water softener standpipe could be lower. Furnace or AC condensation would not need a condensate pump.

For avoiding a trap primer, see the items mentioned in this thread: https://terrylove.com/forums/index.php?threads/backflow-protection-waterless-trap-seal.89152

I understand you are not worried about sewer backup.

 

[WorthFlorida]

No matter what a good selling point, one day, is another toilet in the lower level. Going under the foundation makes it real easy to add any kind of appliance. Having a bathroom at the walk out basement level allows for a full bathroom and no walking up steps from the outside. Depending on your dad's age, someday the steps can be hard to handle. Just pure convenience.

 

[Reach4]

A shower near an outside basement door could be nice when you get really messy, and don't want to track stuff into the house. Encounter with a skunk by your dad or his dog might be another case where a basement shower could be useful.

 

[Steven Whitehead]

A shower near an outside basement door could be nice when you get really messy, and don't want to track stuff into the house. Encounter with a skunk by your dad or his dog might be another case where a basement shower could be useful.

Good Point about the value of a *possible* f

Laundry sink, or laundry standpipe in the basement. Water softener standpipe could be lower. Furnace or AC condensation would not need a condensate pump.

For avoiding a trap primer, see the items mentioned in this thread: https://terrylove.com/forums/index.php?threads/backflow-protection-waterless-trap-seal.89152

I understand you are not worried about sewer backup.

Reach (and others too),
Thanks for the pointer re: backflow protection and avoiding a primer. Those look like good options, especially the test plug. Nice and simple
Also, Thanks you for pointing out the potential benefit of a toilet or even shower in the basement. I hadn't planned on it, but it may be worth considering. (I'm trying to keep things simple, but it may be worth the effort to add/plan for a basement toilet or shower). My thinking had been that if in the future I wanted to add a toilet in the basement, I could go with one of those 'upflush' toilets with a macerator/pump. But on further reading I see that macerators/pumps aren't recommended for use when waste drains to a septic system. (Apparently, the macerator grinds the waste up into too fine of particles, which clogs the drainfield). So maybe that isn't an option after all.

I honestly hadn't thought about a shower in the basement.

I'm still on the fence with respect to putting in a toilet or shower in the basement. I don't think my dad wants that. I think he has other plans for that space. Still, I'll definitely talk it over with him. And even if we don't put a toilet/shower (or other) in the basement now, plumbing the house drain through the floor, at least leaves the option open in the future, even if it would involve tearing up the slab. That seems like a good reason to go through the floor/under the footing vs through the wall. (Of course, if we're eventually going to do something in the basement (toilet or shower) or furnace or whatever, it'd be best to plumb for it now (before the slab goes down).

As for sewer backup, we'll be on a private septic system. If we have a problem in the septic system, we could definitely have a backup, maybe not as bad as a public system, but still it's definitely possible. And of course, I'd like to prevent it from backing up onto the basement floor. Better to have it back-up into the basement's utility/laundry sink. So if we go for a drain in the basement floor, I'll definitely want to use one of those backup protection devices you referenced.

Thanks again for your help. At this point, I'm leaning toward going under the floor.
Any other thoughts, suggestions are most appreciated.

Kind regards,
-Steve

 

[Steven Whitehead]

No matter what a good selling point, one day, is another toilet in the lower level. Going under the foundation makes it real easy to add any kind of appliance. Having a bathroom at the walk out basement level allows for a full bathroom and no walking up steps from the outside. Depending on your dad's age, someday the steps can be hard to handle. Just pure convenience.

Great point.

 

[Steven Whitehead]

A follow-up question: Given that it makes sense to leave the door open for a future bathroom in the basement. If I can *reasonably* figure out where those fixtures would likely go, does it make sense to pre-plumb for them now, even if we have no immediate plans to use them? That is, is it feasible and reasonable to plumb for say a toilet, shower, wc in the basement, even if I have no immediate intention of installing them now. .. and may never. Instead, I'd just stub them out and seal them off...until we want them down the road. Or should we just tear up the slab, if/when we want to install a bathroom in the basement?

Thanks for your help!

 

[Reach4]

I'm still on the fence with respect to putting in a toilet or shower in the basement.

Midway choice its to rough in the basement bathroom.

Another bathroom brings buyers looking at listing.

Edit: I had not looked at your latest post... so yes, makes sense.

 

[WorthFlorida]

A follow-up question: Given that it makes sense to leave the door open for a future bathroom in the basement. If I can *reasonably* figure out where those fixtures would likely go, does it make sense to pre-plumb for them now, even if we have no immediate plans to use them? That is, is it feasible and reasonable to plumb for say a toilet, shower, wc in the basement, even if I have no immediate intention of installing them now. .. and may never. Instead, I'd just stub them out and seal them off...until we want them down the road. Or should we just tear up the slab, if/when we want to install a bathroom in the basement? Thanks for your help!

Get it rough in and it will be left with a rough in inspection only. You don't want to be cutting concrete later on and dealing with venting to the roof with a finished house. Cost wise it be small compared to after the build. Without water fixtures or a room there be no hit on the assessment.

 

[Jeff H Young]

Thanks Jeff. I had thought about adding a floor drain, but have hesitated, since this is a vacation home and I worry about a basement drain's P-trap drying out and stinking up the place, especially during those long winter months when the place might be vacant. For simplicity I didn't want to add a 'trap primer' to keep a basement floor drain's trap full. (Again, off-gridish house w/ limited electric during winter months etc). I suppose I could add a 'vapour block' product (like "Brodi vapour block") or perhaps RV antifreeze (?) to help prevent the a basement drain trap from drying out during long periods of absense... But instead, since I don't have any known need for a basement floor drain (though it'd be nice), I've been leaning towards going without one. Besides a floor drain, are there other reasons you'd go through the floor?
Thanks!

All the reasons others have bought up. future plumbing fixtures etc. perhaps being on a slope you could just run a drain out to daylight w no trap . BTW you can pour something down that wont dry like a water souluble oil or something not sure.
Its your house If you dont want anything down there and adamant about it no biggie , save a few bucks and you know youll never use it and resale value not an issue .