I have several questions regarding basement floor plumbing/drains. However, I will keep it simple and take one issue at a time.
When setting up to pour the basement slab, how do you set a toilet flange to insure that it stays put and that it will be flush with the floor? Do you just set the drain pipe such that it sticks up several inches or feet and later cut it off and afix a flange? ????
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Replies
Typical around here is to let the 4" PVC stick above the floor.
After the floor is poured, the pipe is cut flush to the floor and a toilet flange that slides inside the pipe is installed.
Terry
TLE:
Great! Makes sense!
Now what about tubs and showers?
1. First off you have P-traps. I asssume there is no issue here since you just set them so as to be set in or below the poured floor. Right?
2. Do you again just extend the pipe up and cut it off later?
3. How do you install the tub or shower after the fact? I have installed tubs before and could always work from below or through a wall.
4. Is the placement of these drains a real dog? Once "poured in concrete" there is no for giveness. If you have a toilet and a tub to go in along one wall in the basement and one of the drains is off, you have a problem. NO?
Are you doing the roughin yourself?
For shower and tube traps below grade you set them and stub the tailpieces up out of the slab. I drive a piece of rebar beside each, cap it and tie red flagging tape to both the rebar and the pipe to alert the concrete crew not to knock them around.
Around here the roughin has to pass a wet test inspection before the floor can be poured. That means everything below the slab has to be in place.
If you are subing out the plumbing, your plumber will know how, when and what to do. Just check his layout to the prints. Missing a stub out on a plumbing wall or tube drain by a 1/2" or even an 1" may mean some minor adjustments in the plans, but a big miss can mean jack out the floor to straighten out a bad layout.
Dave
we also require a piped water supply to all our in floor basement p-traps ..
wane,
I have heard that for floor drains but not drains for fixtures. Good grief! Are you erious? For all basement tubs, showers, and sinks?
just floor drains ..
>>we also require a piped water supply to all our in floor basement p-traps ..
Why is that?
As I understand it, it is to insure the drain stays wet (the trap stays full of water) to prevent sewer gases from getting into the house.
I think it is a nice idea, but a bit silly. People with modern plumbing lived fine without wet drains. If one were to dryout and start to smell, pour a cup of water down the drain. Of course that is assuming that the owner has a lick of sense. Ok, I gues we do need to require wet codes, we are not dealing with the mentality of our grandfathers anymore. LOL!
Obviously the water doesn't run constantly, so is there a float or sensor to turn on the supply when the trap is dry?
Zurn makes a wet trap assembly for floor drains, and I guess they could be used for fixture drains, but can't imagine why.
In commercial applications a dry trap is sometimes an issue for floor drains. Most large office buildings with numerous restrooms have floor drains in them. You would think that just normal cleaning would be enough to keep the floor drain traps wet but , not so amazingly, it doesn't happen. A dry trap in a floor drain can become a real building stinker. Not good in an enviroment where a lot of people are always looking for an excuse to "go home, because that smell made them sick."
I have never seen a properly vented fixture trap go dry if the fixtures is used at all. I can think of at least two fixtures where I work, that I know haven't been used in 8 months, and the traps of both still have a wet plug in them.
No, I am not a plumber, and I haven't stayed in a Holiday Inn in the past 10 years.
I have also used the block out method for drain pipe locations. Mostly for closet flangs when the roughin is with 3" pipe. It gives me a better shot at having the flang level and at the correct height than if I take chance on the concrete finishers not stepping on it or running into it with a troweling machine.
When doing layouts for rough in below a slab, I drill in tapcons for my stringline anchor points. I use centerline for all wall locations and tub or shower locations. I then pull strings to steel stakes driven outside of my dig area. Marking paint under the string gives me my dig lines, and after I have exgavated, I reset the string lines. I dry fit all of my traps, wyes, tees and ells at fixtures first, then fit the lines between them, adusting everything to plumb and with the proper fall in all drains. After I have it all fit, I make registration marks on all fittings,and double check all measurements from my pull points and string lines. Satisfied that everything is right I start at the lowest end and start glueing pipe and fitting together, again checking measurements as I go. When I get the first group of fitting set, I add enough gravel over them to hold them in place as I move on the the next group. This helps keep me from pulling or pushing something off its mark as I get further along. After it is all glued up, I check it all again, and again before the pour.
Did I mention I am not a plumber?
I am, however , sloooooooow!
Maybe PlumbBob will stop in here and give you the low down on how real plumbers do thier underslab rugh in.
Dave
Dave:
Great post!! Thanks for the details. I still have a few questions.
First, what is this Holiday Inn Stuff?????
SEcondly, you say: I drill in tapcons for my stringline anchor points.
Is this to show where the poured floor will be or is it a sloped line running from the furthest drain to the point where it exits the foundation?
Third, you say "After I have it all fit, I make registration marks on all fittings, . . "
What registration marks? Are these the marks you/plumbers make on all fittings and pipes prior to glue up. Or are you making registration marks as to the depth of you pipes?
>>First, what is this Holiday Inn Stuff?????You've never seen the Holiday Inn TV commercial?
Guys doing brain surgery, fellow doctors congratulate him on a successful operation, ask him how long he has been at it, says first time, "but I did stay at a Holiday Inn last night".
Speaking of trap primers, I ran into that myself, and as a result, the basement has no floor drains... even though the basement drains into a ejector-pump sump system, the authorities were concerned that we would suffer from sewer gases. I considered hiding the piping below the floor and breaking it out later (i.e. just below the surface of the finished floor) but settled on installing drain connections in the walls instead.
At ISH NA, I discovered a rubber duck-bill like insert that is approved in MA and many other jurisdictions to avoid the need for a trap-primer. I used that in the other floor drains of the house, the inspector had to give it to me, and the plumbers were happy that they finally found a simple device to obviate the need, expense, etc. of a trap primer. Obviously, it depends on the local jurisdiction, but the TrapGuard can save you a lot of time and sanity.
Edited 12/4/2005 5:03 pm ET by Constantin
Dave:
Do it myself? Well, perhaps.
I am looking for a lot or a small plot to build and yes I would like to do most of the work myself (minus, concrete work, drywall, and maybe a few other things). I built a house years ago with my father and would like to do it again. Over the years I have ripped bathrooms out and remodeled them including plumbing work. I have replaced several roofs, finsihed a basement including moving the stairs, etc.
I ususally know WHAT I DON'T KNOW, and therefore do a lot of homework. SO I guess you are part of that homework, and I thank you.
Up until recently I was think about a crawlspace and that made the drain issues easier, but recently I began thinking about a basement. So I am thinking about what that entails.
1. First off you have P-traps. I asssume there is no issue here since you just set them so as to be set in or below the poured floor. Right?
If you are refering to sink traps - they are set up just below the bowl, above the floor. Tub or shower drains are of course in the floor.
2. Do you again just extend the pipe up and cut it off later?
Yes
3. How do you install the tub or shower after the fact? I have installed tubs before and could always work from below or through a wall.
Under the tub or shower, in the approximate area of the drain, Frame a small formed area (at finished floor height) about a foot or so square. End the horizontal run of the drain line inside this without attaching the trap. Cap the pipe with some duct tape and fill the form with sand so that concrete stays out of it. After the floor is poured and the surronding tub walls are framed, dig out the sand and position the drain pipe exactly where needed by swinging the trap as needed. It is a hassle to slide the tub down over the drain rather then working from below, but with a little help, it can be done.
4. Is the placement of these drains a real dog? Once "poured in concrete" there is no for giveness. If you have a toilet and a tub to go in along one wall in the basement and one of the drains is off, you have a problem. NO?
Not any real problems as long as you pay attention to your measurements (i.e. figure where your finished wall surface will be and take measurements from there.)
Terry
TLE,
Thanks again.
The idea about the one square foot framed "work zone" makes sense. The other poster responding to me did not mention this.
I suppose there are multiple ways of doing these things, your way is more forgiving.
Naturally, the vent pipes ar stubbed vertically and then extended as well. And I assume there should be no reason to frame out a "work zone" for these, or is that useful as well? (obviously no below grade vent is required for any sinks)
And I assume there should be no reason to frame out a "work zone" for these, or is that useful as well? (obviously no below grade vent is required for any sinks)
You only need to box in for fixtures that alignment is critical. Vent stacks and vanity drains can usually be located in walls that can be placed as needed.
Terry
TLE and dave,
ARe you plumbers by trade?
ARe you plumbers by trade?
No, but I have stayed at a Holiday Inn before.
Terry
I assume that you are putting a tub in an alcove that has no access on either end? If this is so, you have to rough-in the trap right on the money of the tub you are using. The vent should be roughted-in the stud wall behind the trap, this does not have to be boxed in, make sure that its in the wall. The tub trap should be boxed out, sand is good, but another thought is foam insulation, both will work. Your other pipe should be run into the wall where the the fixture is located you will finish the rough-in after the concrete is poured. Toilet; make sure you are on the money, get a closet spacer {plumbing supply] and you are ready for your flange, I.E. they have to be cut off at the finish floor line. Water lines to traps, they are only required when you don't have a fixture connected,[Trap Primer]. Hope I'm helping, but I may be making you more confused. Lots of luck.
Shacko,
I am following you at least 90%.
I get your point about the tub. If you have a framed wall on the end you should be about to at least see what you are doing as you lower the tub to the stub. As for a shower base, at some point as you lower it you must go blind. Or are the final attachments made right through the fiberglass drain? Of course a fully tiled shower stall would be pretty easy as you could just build your drain right on the stub and tile away.
I guess my main concern was the initial placement of stuff and how careful you needed to be.
If you have a framed wall at the drain side of the tub you not only can see what you are doing but you also can modify any mistakes that you make on rough-in. A shower receptor is normally installed by dropping it down on the rough-in, make your measurements exact to the base that you are going to use, [they come with the base] you can put a small box around it in case you have to tweek, do not pour solid concrete around the pipe. Regardless of what the posts say a trap primer is a health device, you wouldn't believe what kind of germs you have in a sewer system; besides the stink. They are not that hard to install. Hope I'm helping.
I would like to add one thing to the good info you have received.
When stubbing plastic DWV pipe out of concrete you should protect the pipe from the concrete. Foam tape, Rubitex, bubble wrap are all excellent ways of doing it.
This does two things one it allows for some movement if your measurement was off slightly. & two it protects the pipe from busting during expansion, settling etc.............
plumbbill,
Bubble wrap, interesting. But can that really give you much to play with in terms of movement? I would think it would be hard to get it to move much even with a half inch of bubble wrap as the drain pipe below is going to be pretty rock solid (embeded in gravel or cement). Maybe an eight of an inche is all you need sometimes ???
Acouple of more questions to all.
When running drains down from the first floor to the basement I would think you would often run these lines very close to teh foundation walls. Therefore, how to do you handle gettting the pipe out away from the wall and avoiding the footing? Do you just plumb a forty-five degree bend right at the slab level to move the pipe out away from the wall and over the footer?
Secondly, often times when footings are poured for the exterior walls of teh foundation additional footings are poured for teh support of interior walls. Do you plan ahead for where drains will need to pass through these footings and therefore leve breaks in the footings. Or do you undermine footings as required and run all your drain lines deeper and thus under these footings? I would think undermining would be a no no.
Parallel undermining is a big no no we use a 1 to 1 rule 1 foot out = 1 foot deep etc.......
Tunneling perpendicular to the foundation is not preferred compared to a block out or sleeve but sometimes elevation require it.
When running drains down from the first floor to the basement I would think you would often run these lines very close to teh foundation walls. Therefore, how to do you handle gettting the pipe out away from the wall and avoiding the footing? Do you just plumb a forty-five degree bend right at the slab level to move the pipe out away from the wall and over the footer?
Quite common when you have pipes in exterior walls, but when we don't have drain lines in exterior walls we go down inside partition walls & avoid foundation walls cause it usually requires less fittings this way.
PLUMB, thank you for your kind and complete posts, but I am not sure a follow a couple of your points.
You say: "Parallel undermining is a big no no we use a 1 to 1 rule 1 foot out = 1 foot deep etc......."
Are you saying that you should not dig or trench parallel to a footing closer than the depth to which you are digging?
You say: "Tunneling perpendicular to the foundation is not preferred compared to a block out or sleeve but sometimes elevation require it."
Please clarify. What is blocking out (with what) or sleeving?
You say you avoid runing down exterior walls along the foundation and perfer interior partition walls.
I was attempting to get to this issue in one of my previous questions. Don't most interior basement partition walls have footers beneth them? Most would be bearing walls to support the first floor. This footer would have been poured at the time of the perimeter footing and before any drain lines are run. Do you plan ahead for this and box out a hole through the interior footing? If so you would still end up digging under teh footing to finish teh drain work (not the best idea).
I guess a simple example would be a 30 by 60 basement with a bearing wall dow the middle lenghtwise. Then lets say you run a drain down the back wall of the basement and need to exit the basement at the front. How do you plan to get the drain under the footing in the middle of teh basement?
Around here perimeter basement footings are formed and poured first. Then interior footing are poured monolithic with the slab. This is sometimes refered to as a thickened slab where load bearing walls will be placed durring framing. It has the advantage of reducing the total lf of footing that need to poured by the foundation sub, and allows the plumber to rough all the stuff beneath the slab without having to tunnel under interior footings. Both reduce the cost of the foundation and plumbing rough in. The flat work sub generally charges by the sq. ft., not the thickness of the slab, so a thicken slab or monolithic footing in the slab doesn't cost you anymore than the total square foot charge of placing and finishing.
Dave
Dave, makes sense. I have seen dozens of basements around here poured with separate interior wall footings. So don't know if anyone does the mono-pour thing. I would have to look into that.
The interior formed footings I see around here are for poured walls. I have seen more and more safe rooms being built into basements. Even seen a few with poured concrete ceilings or caps on them, knd of like the old bomb shelters of the fifties and sixties.
BTW, I nevere answered you on the tapcon question, and did see if someone else did either.
After you footings and foundation walls are poured you need to lay out your interior walls for your plumbing rough in. Your measurements are made from the inside of the new foundation. Instead of just marking the center line location of the interior partion walls on the exposed footings and/or walls, I drill in a tapcon on those marks. They become permanent pins for all future layout work so I and others don't have to keep repeating the layout procedure. They are also excellent anchor points for my string lines. Wooden or steel stakes as pull points around the perimeter get bumped or even pulled off mark by a tight string line, my tapcons don't. It also keeps everyone else on a job from ending up with a slightly different layout than me. If we are all are using the same pins as starting points, the rest is just staying square, level and plumb.
Dave
DAve, thanks again. Great tips!
Do plumbers typically try to run as much as possible all the drain lines from the first floor between the joists in the basement and only drop down to exit the foundation near the sewer line or septic line? For example if a first floor bath is on the front of the house and the septic exits at the back, do the plumbers drop strainght down from teh bath to teh slab and go under the slab all the way to the back of the house or do they run the drain accros teh house between teh joist and only drop down when they get to the back of teh house?
I see advantages to both.
I'm not a plumber, so I may do things differently on this particular one.
For long waste runs in the floor joist bay area I calculate the amount of total fall for the lenght of the run. If it takes the pipe below the joist, and the basement will be finished, I reroute it to a chase wall in the basement and take it under the slab. If the distance is not to great and the waste line stays up inside the joist bays, I try to get then as close to the main sewer line as possible, the make the drop and tie in. I have finished way to many basements where I have had to build soffits around waste lines, or drop the ceiling a little lower than I wanted to, because of waste lines that transit beneath the floor joist.
It is more a judgement call in my book, than a cost or ease of installation one. For many residential plumbers, if they are not to do otherwise, they try to keep as much of the DWV system out from under the slab as posssible. For your own house, you need to think of what your future plans are for the basement in terms of living areas and unfinished areas, as well as being able to access cleanouts points if there is ever a waste line blockage. The more you plan before you build, the fewer "ah $hids, I should thought of that..." moments you have after you have lived there a while.
Dave
DAve, thanks again.
Planning? Do people do that? LOL.
It seems to me that so often the builder builds ie frames adn then the plumber is left to figure out how to get the job done. That is why joists get cut, etc. because the plumbing was not built into the plan. Natural there had to be some design considerations but not to the level of detail you are talking about to avoid bastard drain lines running through a basement family room.
I can see your ponit about running between the bays if possible, but as you say at 1/4 inche drop per foot, you can't stay in there with a 3 inche drain line for more than 20 or so feet (assuming 9 1/4 inche 2 x 10 joists). So front to back of a house could be a stretch.
If there is room overhead to run the drain pipe without being to low cause of a ceiling I like to run in joist space.
Easier to put in a hanger than dig a trench.
First Q = yes
Second Q --- I was thinking more of a crawler than a basement but we do sleeve them when applicable. Blocking is usually done with rigid foam- holds up well during the pour & easy to remove after concrete has set.
Sleeving is done with a larger pipe anchored to the forms than you plan on running.
I.E 4" pipe sleeve for 3" pipe etc.......
I have a finished slab on grade basement I have 9 interior walls & only one of them is load bearing. My bathrooms are stacked so that was a no brainer for the plumber who did the work back 75'. My kitchen sink line was ran in an extort wall until it was over the laundry wall then it dropped down that wall pick up the auto washer then into the ground.
when I relocated my basement toilet a couple of feet I noticed the main horizontal drain was very shallow, not having seen where it actually crosses my footing I can surmise from experience that it either goes just under the footing ----- or a sleeve or block-out was set in the footing.
Most of the time plumbers are not fortunate to be on site when main footing are formed & poured , so you either get a decent builder who puts in a block-out where the main drain is going to exit, or a not so decent builder who puts it in the wrong spot or none at all.
In that case we usually tunnel under the footing or coredrill depending on the depth of the footing.
& to your 30x60 example---- we start our plumbing at the fixed point for example a bathroom at the far end is a fixed highpoint good average is the start of I-E (invert elevation) to be 1' below finish slab & grade down 1/4" per foot to the exit point of the building
Now if this passes an interior footing putting rigid foam in the form ( giving yourself a couple of inches of play is nice too) for a block out works well.
If it is deeper than the footing you can run pipe first backfill & compact or tunnel later.
Sometimes you have a fixed low point of connection then we start there & grade up to the farthest fixture same principal as before just starting at the other end. this is where 1/4" per foot can run you out of a slab sometimes ------ You can run 4" & larger pipe 1/8" per foot but you have to get inspectors permission first
I have never been denied this when the math says you have to put a toilet on a 1' riser of concrete to get that 1/4" per foot grade.
Hope this helps ya.
Yeah I thought bubble wrap was different too when the northwest president of IAPMO told me I could use it when I was out of rubitex.
But when I do use it I wrap it a couple of times so I can remove some for more movement if needed.
& when doing tubs I put in a block out like others have posted.