Thread: New Home - Pluming in wrong place cut into concrete slab

Hello,
We are having a new house built and one of the bathroom has the plumbing rough in off by a couple feet. The builder is going move the pipes to the correct location but I'm very concerned that this may cause issues in the future with the slab. It's a post tension slab (cables have not been pulled). The builder is not going to cut any of the cables. What are your thoughts on this and this should be corrected. Thanks

Originally Posted by Daniel Gonzales

Hello,
We are having a new house built and one of the bathroom has the plumbing rough in off by a couple feet. The builder is going move the pipes to the correct location but I'm very concerned that this may cause issues in the future with the slab. It's a post tension slab (cables have not been pulled). The builder is not going to cut any of the cables. What are your thoughts on this and this should be corrected. Thanks

It is not uncommon for the Plumber to be off by inches and many times the wall needs to be furred out to hide the mistake. I don't envy the Plumber that has to work around cables after jack hammering the concrete, cutting through the moisture barrier, removing sand and digging new ditches to accommodate the new piping....much less making the tie-in and capping off the mistake. This is a major screw up and will cost the Plumber a good portion of any profit on the job. Good luck and hope that he fixes it properly.

This will be a pain in the arse for the plumber but can be done without causing a problem for your slab. Monitor the work, document the repair, and you might consult your attorney if you should put the builder on notice about future action if this repair causes problems in the future. But, fwiw, I wouldn't loose sleep over this. I had to move a shower drain in a home I owned 15 years ago. I did the entire job in four hours. But it was a pain......

To put you at ease, there is no great concern if there are no tendons within the two feet of concrete to be removed. That said, however, if I were in your shoes, I would insist on having an independent engineer, preferably a structural engineer with PT slab experience, sign off on it. Negotiate with your general contractor over reimbursement as you should not be paying for the engineer. It will be a minimum of four hours of time, maybe six, at around $150-$200 for a good SE.

Wow, two feet on a PT slab. It happens, but that's what keeps us up at night (I'm a general contractor who builds multi-family housing in southern California, and we use a LOT of PT slabs).

Originally Posted by CoronadoBruin

....., I would insist on having an independent engineer, preferably a structural engineer with PT slab experience, sign off on it.

I would insist that the engineer who designed the slab inspect and approve the fix, as well as the Special Inspector.

Originally Posted by Loren Sanders Sr.

It is not uncommon for the Plumber to be off by inches and many times the wall needs to be furred out to hide the mistake. I don't envy the Plumber that has to work around cables after jack hammering the concrete, cutting through the moisture barrier, removing sand and digging new ditches to accommodate the new piping....much less making the tie-in and capping off the mistake. This is a major screw up and will cost the Plumber a good portion of any profit on the job. Good luck and hope that he fixes it properly.

I agree with all that was said, but also I would require that the engineer you use create a documented repair and inspection plan that has check lists etc as well as dimensions. depth and slope requirements for the plumbing. If those can not be met, then the plumber will have greater problems than a "repair". Also I would have the engineer himself be the inspector. This is CHEAP insurance even if it costs the plumber a lot of money.

Be sure that NO PT cables are nicked or cut in any way. I have seen jobs where cables are cut and it creates major issues. I have seen them actually break concrete as they unravel. Makes a real mess.

It is done all the time to make repairs, correction incorrect locations, or even make changes - no problems ...

... PROVIDED that no cables are damaged in any way ...

... AND no plumbing is too close to a PT cable (I've seen PT cable slice through PVC underground pipes (when the pipes/cables were located improperly in relation to each other) when the PT cables are tensioned.

... (I've seen PT cable slice through PVC underground pipes (when the pipes/cables were located improperly in relation to each other) when the PT cables are tensioned.[/QUOTE]


I have known other people to make this statement, but I don't understand the mechanism. If the cables are imbedded, they don't move appreciably when they are tensioned. If they are not imbedded, there are much bigger problems than a damaged pipe. Please, teach me.

Originally Posted by Darrel Hood

... (I've seen PT cable slice through PVC underground pipes (when the pipes/cables were located improperly in relation to each other) when the PT cables are tensioned.

I have known other people to make this statement, but I don't understand the mechanism. If the cables are imbedded, they don't move appreciably when they are tensioned. If they are not imbedded, there are much bigger problems than a damaged pipe. Please, teach me.[/QUOTE]

The cables are laid with a curve around a PVC, the cable is tensioned, the tensioning pulls the cable straight and slices through the PVC. I have seen it happen too.

In some PT slabs I inspected, I noticed they were running the cables curved around some PVC, I had them relocate the cables straighter (which went between two PVC pipes) - when the cables were tensioned, the elongation was correct. When the cables pull through the PVC, the elongation gets way out of whack - much longer and much more pulling that should have been ... a sign that either a cable broke or pulled through something (if the cable never tensions, it was broken and will eventually be pulled all the way out of the slab, if the cable tensions but the elongation is just much too long, it pulled straight and sliced through something).