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Jabberwocky
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# Posted: 11 Oct 2016 09:34am
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Welp, after three years of planning for our next home, my wife and I have decided to build a 600 sq. ft. apartment within a large preexisting pole barn structure. This shop building has an existing 4" slab already poured. My options for adding plumbing and drain lines are:
A) Cut, break up, and remove the existing foundation in the appropriate places and re-pour after the rough plumbing is in place, or
B) Build a raised platform in the appropriate area (where the tub, toilet, sink, etc.. is and run the plumbing above the slab, exiting discretely through the backside of the building.
I'm curious as to what you other folks here would prefer and why.
Just to predicate, the floor plan is being designed in such a way that the main drain line will be very straightforward, regardless of what will happen with the floor. The raised floor idea would necessitate having to step up (about two steps) to enter the bathroom area. There would still be plenty of ceiling height.
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DaveBell
Moderator
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# Posted: 11 Oct 2016 12:02pm - Edited by: DaveBell
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A bath or shower need a P-Trap under the slab. Other drains use a P-Trap above the slab. (Toilet has P-Trap built in) Having all the drains on one side makes things easier. I have done this at home using quick set concrete to fix a toilet drain. I would hammer/chisel out the holes, dig out the dirt outside, install the plumbing, fill it all back in, and Bob's Your Uncle.
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Ontario lakeside
Member
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# Posted: 11 Oct 2016 12:04pm
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Why not raise the whole 600sf up to accommodate the plumbing and insulation. keeping everything on one level.
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Nate R
Member
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# Posted: 11 Oct 2016 01:10pm
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Toilets don't need traps......They come with them!
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DaveBell
Moderator
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# Posted: 11 Oct 2016 02:39pm
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Thanks Nate, made the change/edit.
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Jabberwocky
Member
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# Posted: 11 Oct 2016 06:08pm
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Quoting: Ontario lakeside Why not raise the whole 600sf up to accommodate the plumbing and insulation. keeping everything on one level.
Too costly and unnecessary considering there's a perfectly good slab to build on. To each his own, but I'd rather step up to go into the bathroom than spend twice as much on a subfloor for the whole house.
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Jabberwocky
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# Posted: 11 Oct 2016 06:12pm
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Quoting: DaveBell A bath or shower need a J-Trap under the slab. Other drains use a J-Trap above the slab. (Toilet has J-Trap built in) Having all the drains on one side makes things easier. I have done this at home using quick set concrete to fix a toilet drain. I would hammer/chisel out the holes, dig out the dirt outside, install the plumbing, fill it all back in, and Bob's Your Uncle.
Right, and the raised floor would accommodate P-traps (J-traps). I'm just not sure I want to cut out 20 linear feet of concrete and re-seal it off and be unable to ever perform repairs on it in the future (as unlikely as that may be). Also the raised floor will provide badly needed storage areas for our small apartment.
As you can probably tell, I'm leaning towards the raised platform idea... perhaps a better question would have been "Can anyone tell me a good reason for not doing it?"
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Nate R
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# Posted: 11 Oct 2016 06:17pm
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The only thing I come up with is if you don't have enough headroom above the shower/bath. But otherwise, I don't think there's any reason you should NOT do the step up. Careful when you think about how you'd have room for a standard door height, etc.
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1tentman
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# Posted: 11 Oct 2016 06:22pm
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Is your floor plan set up so the bathroom and kitchen area is against a outside wall of the building, if so you could tunnel under the floor and cut holes for your plumbing.Then connect them outside the building in a main trunk line to your septic.Set them up this way and you would only have to tunnel about 3 ft or less under floor
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1tentman
Member
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# Posted: 11 Oct 2016 06:37pm
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One reason you may not want to raise it is the older you get the least amount of steps the better, even though you say it will only be a couple of steps some day those couple of steps might look like a mountian if your health starts getting bad, just a thought.
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DaveBell
Moderator
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# Posted: 11 Oct 2016 07:53pm - Edited by: DaveBell
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Quoting: Jabberwocky hammer/chisel out the holes
Quoting: Jabberwocky not sure I want to cut out 20 linear feet of concrete
??
Are you planning on putting water supply/drains in the middle of the slab?
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Steve_S
Member
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# Posted: 12 Oct 2016 05:37am
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As an alternative to P-Traps you can use waterless traps such as this http://www.hepvo.com/ which can save space, be freeze safe and more. There are other similar ones out there as well if you want to shop it around, I found these thanks to an article on Tiny Houses a couple of years back. RV'ers & Boater's use them, which is a good reference IMO.
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Jabberwocky
Member
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# Posted: 12 Oct 2016 09:31am
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Nate R
Headroom won't be a problem... I've already accounted for it.
1tentman
The shop is 30x60 with 20x60 lean-tos on either side - all slab concrete. The plan is to fill in a portion of one of the lean-tos with the apartment. The best layout we have come up with allows for the kitchen and bathroom to butt-up to each other, but will not be against an exterior wall. they will be against the inside wall (on the other side of the wall is the 30x60 enclosed shop). As for getting older, it's a valid concern, but my wife and I are in our thirties and we aren't planning on this being a long-term living arrangement (it's not our retirement home or anything, just our best option for what we are trying to accomplish right now).
DaveBell
There is no plumbing in the building right now. All drain lines have to be installed from scratch, and as mentioned above, it is not possible to place the plumbing fixtures in such a way that they are close to the edge of the slab, otherwise yes, I could drill a 3" hole and tunnel in from the side to meet up with it. As it actually stands, it will require removal of several linear feet of slab to install the 3" drain pipe.
Steve_S
The Hepvo valve is a clever concept. I love the ease of installation and no need for vent plumbing. After reading about it on some forums, it would appear the lifespan may be around 6 years. I think I will stick with standard P-traps that don't rely on a mechanical component to function. As a side note, I couldn't watch the Hepvo Youtube video without snickering like Bevis and Butthead.... The look of the thing just makes me think dirty thoughts LOL.
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Steve_S
Member
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# Posted: 12 Oct 2016 11:52am
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Well, my plumbing is "surface run" as I did not put holes in my slab nor into my walls for pipes. My cabin was built with that in mind so my Grey Water system exits into an insulated box which then runs underground into the reservoir tank that dumps into the two drain runs.
Toilet is a composter and I will be adding a urinal for obvious reasons.
Raised platform under the shower to accommodate my drain pipes.
The Hepvo units are not unique, there are other similarly designed ones but I don't know about the brands as such, you could search for them. Worst Case scenario you may need a Sewage Pump / grinder type unit to pump waste out to your septic. All of this depends on how you design your waste water management but busting up a slab is fraught with potential gotchas both short & long term so taking time to seriously consider options & methods is a worthy exercise... Last thing you want to do is stand in a mess screaming at self & others about "Should've, Could've, Would've" which only makes for grumpiness and drunken sailor talk....
BTW: Many people have converted Garages and other structures that had existing slabs and used different methods... May be worth searching for info on such conversions as I am sure there are creative solutions used that may not have been considered.
One possible idea, is to build an extension to the existing building slab, where you could put all the pipes in and pour a fresh slab over it. Would not have to be too large, just enough to capture the drain lines from kitchen / washroom / laundry (if so equipped). It could be a strip 5' wide by 10' long along a side giving you drain lines etc that could be tapped into. Just a possible idea like the doodle I attached below. Of course however it could fit in... One advantage, it would let you insulate under it prevent pipe freezing issues IF that is a concern.
external add-on slab for dwv
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NorthRick
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# Posted: 13 Oct 2016 01:03am
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If it were mine, I'd cut the concrete and bury the drain line and keep everything at the same level. 20ft ain't that bad with the right cutter. Yeah, more pain and expense up front, but better than tripping over that step half asleep in the middle of the night for years and years.
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toyota_mdt_tech
Member
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# Posted: 13 Oct 2016 08:41am
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Build a bump out with a shed roof for the bathroom or a basin and pump set up into a surge tank which ships it off to a septic system. But need power, off or on grid?
I'd do the bumpout slab, get all plumbing in place, pour slab.
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Jabberwocky
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# Posted: 13 Oct 2016 08:54am
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Thanks guys, all those are good ideas. I'm still working on the layout - didn't have any time at all yesterday. Pictures are worth a thousand words, and if I could upload a picture of the layout, it might change the suggestions somewhat.
We are trying to preserve the view - the west side of the apartment is where we will have space for windows, so we are trying to keep the primary living and traffic spaces to that side, hence the bathroom and plumbing will be against the inside (east) wall. The other side of the east wall of the apartment is the inside of the shop building. For that reason, pouring an extra section of slab for rough plumbing isn't possible.
As for a bump out, it would force us to use the space reserved for the bedroom, which is placed there so as to allow for a bedroom window - a "must-have" according to my wife ;).
I'm sure this sounds confusing without being able to see pictures.... I'll work on that sometime this weekend when I have the chance..
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Steve_S
Member
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# Posted: 13 Oct 2016 09:45am
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Jabber please take this into consideration.
If you cut & excavate a slab, even partly, then refill, compact & pour new cement, what is put under it will never match to the rest of the compacted soil under. This often causes voids / weak spots that haunt you later. Yes it can be done and done right BUT it's not slap dash and away you go. All depends on what has been done under the existing slab. Imagine the look on your face, 5 years later, IF the slab you have cracks up & splits... I know what mine would look like and NO ONE wants to see that nor hear the accompanying drunken sailor talk !
Pictures are certainly worth a 1000 words... post'em and planning doodles would be helpful too.
Sometimes compromise is a necessary evil to attain what you want for the most part. This is especially true when your working with an existing structure, platform or what have you. If you start from scratch and build what you want and how you want it, that goes away but that nails the budget pretty hard.
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Jabberwocky
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# Posted: 14 Oct 2016 08:59am
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Steve_S
Indeed it does. We have tried for going on three years to build our own house on our own land and have investigated countless options on how to go about doing it. It's not a question so much of money - I could be approved for a mortgage in fifteen minutes, but it's more about our priorities. The longer it drags out, the more my wife and I realize that our "must-have" list keeps getting shorter and shorter.
With careful budgeting, we are hoping to construct the apartment using the profit from our previous house sale and not have a mortgage OR rent.
I appreciate the caution about the slab. I'm still leaning toward the raised platform  , but it's a tedious process... I can't design the platform until I know the exact placement of the toilet and tub, because that will allow me to calculate drain slope and thus how tall the platform will be. But I can't determine the exact placement of the plumbing until I know the exact placement of the surrounding walls..  So it's taking some effort and I haven't had time this week..
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Steve_S
Member
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# Posted: 14 Oct 2016 09:11am
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Well don't feel bad about it.. I know sometimes your likely quite frustrated and anxious to "get on with it already" or some such variation...
BTW: NONE of my plumbing is "in or under" concrete, well unless you count the 2, 4" Conduits running from the Power/Pump house to cabin. 1 for water pipe & one for electrical. I refused to corrupt the insulation so internal water is on "surface of wall" and drain lines are surface on the concrete, so "platformed" under shower area... Electrical is also mostly surface with little exceptions when possible & not breaking the thermal envelope. Different, PITA to do and maybe not as "purdy" as some would like but - it is what I envisioned.
Wait a year or maybe two and you could buy my place - seems now that my health and other things are going against me some more again so.... Gonna hang in as long as I can but that no longer looks like as long as I would have liked... Sorta feeling somewhat depressed after the last couple of days of bad, more bad and even more bad news'... Maybe sell it all off sooner and take a last trip before I can't even do that anymore... Ohh Well...
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