# Relocating plumbing - concrete slab foundation



## vsheetz (Sep 28, 2008)

For a coming bathroom remodel I am looking to relocate some drains. Looking to combine existing bathroom with adjacent closet Toilet needs to move about four feet - new location will be on an outside wall. A sink drain will needs to move about three feet and then provide for a tub drain as well. 

Cut a appropriately sized slot in the concrete from old to new location? What are DIY options for opening the concrete slab? Or best to get a pro concrete cutting outfit to come in? 

Thx!


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## Ron6519 (Mar 28, 2007)

There are some slabs that can't be cut. Those that are pre tensioned with metal reinforcement. If yours are not, you can rent a concrete saw and cut channels where you need them. I'd get a wet saw to cut down on the dust.
Make sure you have the pitch needed to move the solid waste from the new toilet location to the main drain. There are limits to this distance.
Ron


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## vsheetz (Sep 28, 2008)

Ron6519 said:


> There are some slabs that can't be cut. Those that are pre tensioned with metal reinforcement. If yours are not, you can rent a concrete saw and cut channels where you need them. I'd get a wet saw to cut down on the dust.
> Make sure you have the pitch needed to move the solid waste from the new toilet location to the main drain. There are limits to this distance.
> Ron


How does one tell if the slab is a tension slab?


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## rossfingal (Mar 20, 2011)

Is the slab you want to cut in a residence (house/condo)?
Slab on grade - basement?
rossfingal


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## Ron6519 (Mar 28, 2007)

vsheetz said:


> How does one tell if the slab is a tension slab?


There might be a mention in the house plans on file with the local municipality. 
Ron


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## vsheetz (Sep 28, 2008)

rossfingal said:


> Is the slab you want to cut in a residence (house/condo)?
> Slab on grade - basement?
> rossfingal



Single family residence
Slab on grade, no basement


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## rossfingal (Mar 20, 2011)

Hi!
Rent the biggest, electric saw (with a diamond blade - for concrete) -
"Wet or Dry" is good.
Probably, it will be 9" to 10" (It depends on what's available in your area).
You can rent gas fired saws (If you like to smell/breathe Carbon Monoxide -
NOT!)
Saw a couple of parallel lines (where you're going to run your waste lines - saw them a little wider then you think you'll need) -
We would saw another line in the middle of the two lines - then: it's
sledge-hammers - electric, jack (rotary) hammers to bust out the concrete
floor (eye protection/dust masks!).
Whether or not the blade is "Wet or Dry" - spray bottle of water can help
to keep the dust down! (Remember: electric saw = a shocking experience!)
Make sure you pitch/slope your drain pipes, to your "plumbing stack"/drain - a slope of 1/4 inch per foot is considered good.
Don't try to saw through the floor, to the total depth that the saw will
allow - use, repeated cuts, deeper and deeper - an 1/8" to a 1/4" to a 1/2" - and so on. (I know - time consuming: but, easier on the saw/blade!).
(Don't try this at home!!) 
We've done this dozens/hundreds? of times - didn't count - don't remember.
It worked.
Hope this helps! 
Regards!
rossfingal
(Glad you're doing it, and not me!! )


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## rossfingal (Mar 20, 2011)

Oh, by the way - "single family residence, slab on grade" - 
it's not "pre-stressed" ("pre-tensioned")!
Regards!
rossfingal


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## rossfingal (Mar 20, 2011)

Another thing to consider is - how far is the existing toilet from the plumbing
"stack"?
There may be "re-vent" considerations for the new toilet/vanity/tub...?
rossfingal


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## vsheetz (Sep 28, 2008)

rossfingal said:


> Another thing to consider is - how far is the existing toilet from the plumbing
> "stack"?
> There may be "re-vent" considerations for the new toilet/vanity/tub...?
> rossfingal


Goal is to arrange/rearrange combined existing closet and bathroom so as to minimize plumbing changes and relocations The move distances will be only one to three feet, which should make things easier. I hope...


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## vsheetz (Sep 28, 2008)

rossfingal said:


> Oh, by the way - "single family residence, slab on grade" -
> it's not "pre-stressed" ("pre-tensioned")!
> Regards!
> rossfingal


I had a house some years ago that was supposedly a tension slab. Single family slab on grade (pilings). Sinking houses were a problem As I understood the idea was for the slab to tilt rather than crack - and then just mud jack it back into level as needed. The house came with a written guarantee against cracked slab for X number of years.


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## rossfingal (Mar 20, 2011)

I'm not talking about whether or not the "slab" is "pre-stressed" (pre-tensioned) - your current house is not on a "pre-tensioned slab - is it?
If not - saw the floor - reroute the drain lines.
As long as the drain lines are not too far from the "stack" - you should have no problems.
There might be "venting" considerations.
Is your house on "pilings/piers"?
(Yes, 2 or 3 feet can possibly, create a problem - trying to get enough
info, so that does not happen).
rossfingal


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## vsheetz (Sep 28, 2008)

rossfingal said:


> I'm not talking about whether or not the "slab" is "pre-stressed" (pre-tensioned) - your current house is not on a "pre-tensioned slab - is it?
> If not - saw the floor - reroute the drain lines.
> As long as the drain lines are not too far from the "stack" - you should have no problems.
> There might be "venting" considerations.
> ...


Likely not a tensioned slab - this item was mentioned here to be aware of, hence some discussion of it. No pilings or piers.

Gathering info for planning and prep purposes at this time. Once we get into the project will have all the specifics and can then go into details.

Thanks all!


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## rossfingal (Mar 20, 2011)

Just trying to help, if possible!
Regards!
rossfingal


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## AndyGump (Sep 26, 2010)

Most post-tensioned slabs will have an embossing in the slab in one or two places, usually by the garage door saying something to the effect that this is a post tensioned slab.
You really couldn't miss them if they were there.
You will also have to prepare the cut concrete section like it was a new slab when you pour the patch for it. Drill and epoxy holes for rebar to connect old to new, compacted gravel and/or sand, 6 mil. vapor barrier, etc.

Andy.


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## vsheetz (Sep 28, 2008)

rossfingal said:


> Just trying to help, if possible!
> Regards!
> rossfingal


Yes, and the help is appreciated! 
Did not mean to convey otherwise if I did.


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## vsheetz (Sep 28, 2008)

AndyGump said:


> Most post-tensioned slabs will have an embossing in the slab in one or two places, usually by the garage door saying something to the effect that this is a post tensioned slab.
> You really couldn't miss them if they were there.
> You will also have to prepare the cut concrete section like it was a new slab when you pour the patch for it. Drill and epoxy holes for rebar to connect old to new, compacted gravel and/or sand, 6 mil. vapor barrier, etc.
> 
> Andy.


Thanks - I had not given much thought to closing up the holes, just making them.


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## rossfingal (Mar 20, 2011)

@AndyGump
Thanks!

@vsheetz
Yeah, closing up the holes is a lot more "fun"(??) - than making them! 

rossfingal


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