Wastewater pipe concreted in the floor slab at the wrong location

Hello,

yesterday our foundation slab was poured. Today we were on site and the basement walls were marked. We noticed that in one room, which is a living space and will also have underfloor heating, the drain pipe for a utility sink does not come directly out of the foundation slab near the wall but approximately 1 meter away in the middle of the room. All the others come out at the correct locations directly next to the walls.

When I asked the construction manager what that was about, he said casually: "The guys probably measured wrong." But that wouldn’t be a problem at all. They would simply use a thinner drain pipe (50 mm) and lay it in the insulation on the foundation slab under the underfloor heating to the drain.

Now my question is: Is this correct? Does this constitute a defect? Will this create a thermal bridge in the insulated house? Or shouldn’t we accept it like this?

Thanks in advance for your answers.

Exactly the same thing happened to us, and exactly the same solution was proposed to us.

We built without a basement, directly with the floor slab. It is made more difficult by the fact that the "temporary pipe" would have to be routed through a wall (wooden frame) and the entire wastewater pipe is supposed to be for a shower, the exact design of which we do not yet know (because it has not yet been decided --> still all in the early shell construction phase). However, if this solution were implemented, we would probably be limited in our decision for the implementation of the shower.

According to the plan, the pipeline of the misplaced connection runs exactly under the spot where the pipe should have been led upwards. My suggestion was: At exactly this spot, break open the floor slab and install a 90° angle there. Done.
The opposing opinion of the company that messed this up was: This is a load-bearing floor slab. The hole would have to be about 50x50cm in size. And that would probably cause problems with the structural integrity.

To me, the temporary pipe solution smells like a cheap standard botched job.

I called my house construction company to have their structural engineer consult on the issue with the load-bearing floor slab. There the temporary pipe solution was also dismissed as standard...
In parallel, a request is running with the installer to see what he thinks of this solution....

I am curious how it will continue. Will report...

I don't see a problem there, 50mm HT pipe is often laid on the ceiling like that to connect showers, bathtubs, or washbasins to the downpipes. Only the necessary slope should be maintained, but with 1.00 m it should not be a problem. If the basement becomes living space, you probably have at least 100 mm insulation on the floor anyway, so another 50 mm coverage, right? Personally, I wouldn't have any concerns with this solution; mistakes unfortunately happen from time to time.

So, there is news:

I was advised by several parties against opening the floor slab. It’s not just about opening it. No, you have to go completely through the floor slab down into the ground. That’s where the pipe is that you need to access to fix the issue. From a structural standpoint, however, there are no concerns (OK, I have approval from the structural engineer).

The solution with the 50mm pipe going through the wall into the hallway still does not suit me. If something were to happen there, then I'd have the clean/dirty in two rooms.

But my installer said he could easily use another drain in the bathroom. It is 2.5m away, but with the floor construction of about 16cm to the finished floor covering, there is enough slope.

The problem now is different:

The builder now wants to solve the problem by only paying for the solution with the 50mm pipe through the wall into the hallway. He says if it costs 100-200 EUR, that would already be a lot.

But I don’t want to be dismissed that easily. After all, he made a serious mistake and must take appropriate responsibility.

The question to the experts here:

Roughly estimated: What would it cost to open a nearly 30cm thick floor slab with steel reinforcement over an area of 50x50cm, connect a 100mm pipe underneath and properly close everything again. It should of course be taken into account that somewhere in the floor slab construction there is film/fleece and the like that must be properly sealed again.

Because this is more or less the amount in dispute here.

The person from the house building company (who are not to blame for the error, but are very accommodating when it comes to information and help with problems) said: "This can easily keep 2 men busy for 2 days. Roughly 20 hours at 50 EUR each. It will certainly start at 600-800 EUR."

20h * 50 EUR would be 1000 EUR.

Is this rough calculation about right? Can anyone confirm this?

Regards Alex

Sorry Alex, but I think you are exaggerating. As long as the solution is technically sound, it's not a big deal that the pipe comes out somewhere else. Once there is screed on it, you won't even notice. You don't have any restrictions because of it. Why do you want to make a big deal out of it? There will be many other things coming,...

Sorry, I didn’t express myself clearly enough...

Since I was advised against opening the floor slab by several parties, I now want to take the route proposed by the installer: connecting a 50mm HT pipe inside the bathroom to another drain.

However, the builder only wants to cover the cost scope of this solution. That’s where the catch is:

The value in dispute for the error is the cost of producing the item as planned. And that would be, roughly estimated by the timber house builder, 1000 EUR. The alternative solution with the 50mm HT pipe, which he doesn’t even provide, but someone else does, costs less than 100 EUR. That will get lost in the installation bill...

An example:

If I order a blue car from the dealer and the car is delivered in red, I’m not satisfied with a real-fur fox tail worth 100 EUR on the antenna to "beautify the wrong color." If the repainting cost 1000 EUR, then it would have to be more than just the 100 EUR. Possibly an option would be a set of aluminum rims for 800 EUR. I would be willing to let the remaining 200 EUR slide. There should somehow be a gesture of goodwill.

Therefore, here is the question: Is the rough calculation regarding production of the item as planned (this is probably how a building expert would also calculate) accurate at 1000 EUR?

I am not insisting on the payout of the 1000 EUR. I just have something else for him to do that will probably fall within that price range. But for further argumentation (he is currently completely obstructive) it would be helpful to know the approximate value in dispute (opening the floor slab, making the connection, professionally sealing it). I could ask him directly. But since he is obstructing, I probably can’t expect a useful answer here.

Best regards Alex