ᐅ Additional Costs Due to Revised Structural Engineering Calculations

Hello everyone,

We are currently in the final stages of our detailed planning. We wanted to convert a bathroom with a shower into a pantry and a guest WC. This would involve moving a wall on the ground floor by 45cm (18 inches) and adding an additional wall on the ground floor to divide the former shower bathroom. So far, we have not signed off on the detailed planning, but now we are being asked to pay €1500 net for a new structural calculation. Is this common practice?

I had assumed that the structural engineering would only be calculated after completing the detailed planning.

What do you think? Do I really have to cover the cost of a new calculation?

Unfortunately, there is still too little information. If it is, for example, a prefab house with “off-the-shelf” structural calculations, that could be the case. Otherwise, simply ask politely for the reasons and share your thought process openly. Please make sure to communicate thoroughly with the structural engineer and exchange written notes after discussions (email, meeting notes as agreed today, etc.).

Feel free to also generally use the planning thread with plans, floor plans, and so on.

i_b_n_a_n schrieb:

Unfortunately, there is still not enough information. If it is, for example, a prefab house with a standard structural calculation, that could be the case. Otherwise, just politely ask directly for the reasons and explain your thought process openly. Please make sure to communicate sufficiently with the general contractor and exchange written notes after conversations (email, meeting minutes as discussed today, etc.)

Feel free to also generally use the planning thread with plans, floor plans, and so on.

This is a solid construction house, planned freely by us and the general contractor. This was now the third appointment for discussion after repeated errors in the plans, not caused by us. According to the general contractor, the structural calculation is done before the detailed design phase, which, in my opinion, does not make sense. At least, there was never any indication of this.

I understand the general contractor’s position, as they had the structure calculated and would now have to bear the costs twice. On the other hand, the detailed design phase is meant to allow changes to be made and finally approved with a signature. After that, it is clear that no further changes are expected.

Attached are two small pictures illustrating the scope (just as examples).

Here’s how it went for me: floor plan design -> approval -> structural engineering -> detailed design (building permit / planning application) -> execution planning (construction drawings).

Aside from the fact that the execution planning produced for my house didn’t really deserve that name, I find it logical that the structural calculations are done after the floor plans are approved and before the execution planning of the individual trades.

Has the building permit / planning application already been submitted?

Addendum: Without understanding the details, I also can’t imagine that this change would require recalculating the entire structural engineering. But a complete structural calculation definitely costs significantly more than 1500 EUR.

I agree, the detailed construction planning should reflect any necessary changes based on the structural calculation.
Unfortunately, yes, that’s why every word needs to be weighed very carefully. At some point, we got into the habit of ALWAYS asking: What does it cost?
(Before, we often "thought" we roughly knew the cost, but we were clearly wrong several times.)

Okay, it obviously makes sense not to proceed with detailed planning without knowing the structural calculations. However, in the initial detailed plans, no structural calculations had definitely been done yet, that I know of.

I believe we are quite knowledgeable on the subject and have spent a lot of time on the planning process, but sometimes someone else comes up with an idea that hadn’t been considered before.
I also can’t understand how the amount was determined—it seems too high for a small change and too low for a complete structural analysis 😀