Planning errors in garage drainage - are we really liable?

Sorry, but whoever signs says ok, and then also pays....stupid, but that's how it is. Anything else would be goodwill.

Sorry, but whoever signs says ok, and then pays....stupid, but that's how it is. Everything else would be goodwill.

exactly that is not true, because a non-specialist client simply cannot be the control instance for an entire range of construction professionals! Surveyors, planners, draftsmen, architects, structural engineers, authorized submitters, ... have the task of planning a functioning house with their combined expertise.

The signature on the plans only serves to prevent any later discussion along the lines of "I had imagined the kitchen bigger" or "I would have liked a balcony on the bedroom." What you say, Nordlys, would lead to this: one could present technically impossible garbage to the uninformed client, he signs because he can't even properly read the plan, and ends up liable for it.

I would stubbornly insist that as a client you are not an expert and cannot possibly understand and object to the deflection of downpipes in such an extensive drawing. Legally, you are not even qualified to dictate to the architect how to route the water pipes. Otherwise, you wouldn't need professionals anymore. Whether overall it is still sensible to settle amicably given the rather small expected amount is another question!

Just as a general counter-question, who actually pays the architect for adding the garage to the building application for the house? Can I hold the general contractor liable for a service that he only took on as a gesture of goodwill?

Do I understand correctly: the garage cannot be installed as planned because there is a downpipe in its parking space that was not redesigned contrary to the agreement (and now built in that spot as if there were no garage); the connection of the drainage to the sewer is not the point of dispute, but only the costs for rerouting the downpipe around the garage’s footprint?

With developer ties, the general contractor here was probably acting as the developer. Ordering garages "at own expense" bypassing the general contractor is already a popular source of complications – even more so bypassing the developer.

If you are otherwise satisfied – which I would read as defect-free as far as can be seen so far – the sewer connection is not affected and it is only about the costs for the extra work of the tinsmith, then consider it a learning expense and live with the fact that the privately purchased garage was not much cheaper than through the developer.

Other builders in similar situations have completely different problems: namely when installing the garage if the roof overhang of the house already gets in the way of the crane – if you do not have this problem, then there was already more luck than sense at work, I would say, and the rest are peanuts.

Then you wouldn’t need any specialists anymore.

I would completely agree with you if the GU had actually been the G. However, the opening post contains quite a number of terminological inaccuracies that certainly allow doubts about the responsibility.
GU vs. developer
applied for vs. building notification
"planning documents of the garage" vs. "and the planning also takes garage b) into account"
"The error slipped into the building notification" vs. "that we signed the execution plans"
At any rate, it is not clear to me who is responsible for the planning of the garage, especially since garages are exempt from procedures in NI.

We are "actually" satisfied with the company

Then let it rest. You brought it up, the GU does not feel responsible. He will wait it out and possibly delay one or another activity further in annoyance.

Once again, a heartfelt thank you for your answers. I did not want to express myself unclearly; I am apparently not clear on the difference between a developer and a general contractor. The garage comes from an external source, right. For me (as you can tell, a layperson) an externally purchased garage is comparable to a kitchen/a terrace/in other words a self-performed service. In the planning, details must also be considered that do not directly concern the developer/general contractor (e.g. ventilation of a kitchen, chimney or similar). But if our signature releases us from liability, then so be it. We are then glad that it only concerns the downspout and that everything else has gone well.