ᐅ Living area approximately 8 m² smaller in the permit drawings compared to the design (general contractor)
Created on: 16 Apr 2025 11:23
I
ITSM2025
Hi everyone,
Unfortunately, I thought I was smarter than everyone else here in the forum (I have been a quiet reader for a while) and believed I could rely on the general contractor’s planning. Now, right from the start, things are becoming "interesting." I’m not sure whether my frustration is justified or if this is just standard practice in the construction industry. Here’s the situation:
Based on the preliminary design from the general contractor, we awarded the contract (signed the agreement) with the expectation that the room sizes would match the preliminary design. The house is planned as a KfW 40 energy-efficient building with sand-lime brick, insulation, and brick veneer. This was included in the offer along with additional requests, and the design was adjusted accordingly, if necessary. So, it’s not like the general contractor was unaware of our KfW 40 project. Now we have received the building permit drawings showing roughly 8 m² (86 sq ft) less living space due to suddenly thicker walls, both external and internal. The exterior walls were increased from 42.5 cm (17 inches) to 49 cm (19 inches) thickness. And this was done inward, not outward. In other words, each side has lost 6.5 cm (2.5 inches) of interior living space. Calculated in euros, that’s about €22,000 less living area based on the price per square meter. Or, in other words: the general contractor now has to buy fewer sand-lime bricks and build with less material, with less plastering, tiling, screed, underfloor heating, pipes, etc. However, there was no price reduction.
Is this common practice? Should one accept something like this?
Additionally, the attic floor has lost 13 cm (5 inches) in width and 6.5 cm (2.5 inches) of interior height due to the knee wall being shifted further inward. We had planned to convert this space later, which now seems hardly worthwhile. The general contractor knew about this in advance and even planned wiring and such in the attic/roof space.
How do you assess this situation, and how would you proceed?
Thank you very much in advance!
Unfortunately, I thought I was smarter than everyone else here in the forum (I have been a quiet reader for a while) and believed I could rely on the general contractor’s planning. Now, right from the start, things are becoming "interesting." I’m not sure whether my frustration is justified or if this is just standard practice in the construction industry. Here’s the situation:
Based on the preliminary design from the general contractor, we awarded the contract (signed the agreement) with the expectation that the room sizes would match the preliminary design. The house is planned as a KfW 40 energy-efficient building with sand-lime brick, insulation, and brick veneer. This was included in the offer along with additional requests, and the design was adjusted accordingly, if necessary. So, it’s not like the general contractor was unaware of our KfW 40 project. Now we have received the building permit drawings showing roughly 8 m² (86 sq ft) less living space due to suddenly thicker walls, both external and internal. The exterior walls were increased from 42.5 cm (17 inches) to 49 cm (19 inches) thickness. And this was done inward, not outward. In other words, each side has lost 6.5 cm (2.5 inches) of interior living space. Calculated in euros, that’s about €22,000 less living area based on the price per square meter. Or, in other words: the general contractor now has to buy fewer sand-lime bricks and build with less material, with less plastering, tiling, screed, underfloor heating, pipes, etc. However, there was no price reduction.
Is this common practice? Should one accept something like this?
Additionally, the attic floor has lost 13 cm (5 inches) in width and 6.5 cm (2.5 inches) of interior height due to the knee wall being shifted further inward. We had planned to convert this space later, which now seems hardly worthwhile. The general contractor knew about this in advance and even planned wiring and such in the attic/roof space.
How do you assess this situation, and how would you proceed?
Thank you very much in advance!
M
MachsSelbst17 Apr 2025 20:05As already mentioned, these are minor issues, okay.
The mason might place bricks 2cm (0.8 inches) off, someone might forget something, people can get sick, resign, or there might even be an accident, unfortunately sometimes with serious consequences. If this is communicated honestly, everyone understands, even though no client waives contractual penalties because of it.
That is business risk.
But this is something completely different, isn’t it? You want thicker walls and the contractor says, "Fine, I’ll just make the rooms smaller, that’s easier for me. Of course, it will cost extra."
That’s not a mistake due to lack of knowledge or inattention. It doesn’t happen because two employees are sick and the planning is handled by the cleaning staff.
You don’t even want to imagine how things will be handled when real problems occur.
The mason might place bricks 2cm (0.8 inches) off, someone might forget something, people can get sick, resign, or there might even be an accident, unfortunately sometimes with serious consequences. If this is communicated honestly, everyone understands, even though no client waives contractual penalties because of it.
That is business risk.
But this is something completely different, isn’t it? You want thicker walls and the contractor says, "Fine, I’ll just make the rooms smaller, that’s easier for me. Of course, it will cost extra."
That’s not a mistake due to lack of knowledge or inattention. It doesn’t happen because two employees are sick and the planning is handled by the cleaning staff.
You don’t even want to imagine how things will be handled when real problems occur.
@MachsSelbst
Assuming that this is indeed the case. What exactly should the original poster do now, since it has already been proven that the general contractor deliberately and fraudulently treated them?
I have asked this multiple times. What now, and specifically? The OP already knows they were deceived—so why are they still involved with this party?
Please don’t just complain—give a concrete, actionable alternative that will likely lead to a successful outcome for the OP.
I’m curious. I have no solution for them.
Assuming that this is indeed the case. What exactly should the original poster do now, since it has already been proven that the general contractor deliberately and fraudulently treated them?
I have asked this multiple times. What now, and specifically? The OP already knows they were deceived—so why are they still involved with this party?
Please don’t just complain—give a concrete, actionable alternative that will likely lead to a successful outcome for the OP.
I’m curious. I have no solution for them.
Arauki11 schrieb:
It starts with the fact that the original poster, being a long-time reader, should have known that as a layperson they would run into trouble. No, it’s actually much better: although against better judgment and despite all the previous discussions, the original poster went to a general contractor and ended up with a good one who is fulfilling their clearly stated wishes (and will probably also accommodate the previously unspoken request to place the extra thickness on the outside). Excellent!
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
11ant schrieb:
I find it more arrogant to suggest that I only occasionally provide truly useful advice or that my writing is meaningless. On the contrary, I rarely just state something; I often explain in detail why something is a fact—so no one has to blindly trust the all-knowing 11ant, but can understand the reasoning, always gladly in a way understandable to non-experts. However, for an introductory physics seminar aimed at debunking the myth of calcium silicate brick as the only effective barrier against noise, the average layperson usually lacks the necessary background.
I am often misunderstood or perceived as unfriendly in real life, which is an unavoidable consequence of communication across the Asperger ./ neurotypical language divide. Online, where acoustic, body language, facial expression, and other dimensions are missing, I naturally face even more misinterpretations. But should I really stop sharing my expertise just because my straightforward Berlin bluntness might be taken the wrong way in standard German?
The original poster (OP) has a misunderstanding with their general contractor (GC), which looks like a problem emotionally but nothing more. “Blame” is a big, harsh, and inappropriate word for the mutual contributions to a misunderstanding. The fact is that between an agreed-upon drawing of the building contract subject and a preliminary version of the building permit (planning permission) drawings, a change occurred that the OP, as a layperson, did not expect and found confusing. The OP is only “at fault” in their attitude toward the GC, feeling “tricked” and lodging a consumer protection complaint here on the forum, which is objectively unnecessary (as shown in the example of changes to the cross gable, the GC has already demonstrated they are not a cunning customer exploit-er). I then explained the technical context to the OP, clarifying the conflict from a construction perspective and that a draftsman—like the OP and the layperson involved—is not trained to recognize such complications early. Just as the OP likely did not consciously or maliciously give the GC an impossible task (build the exterior walls using EH40 blocks and calcium silicate bricks in size 425), the GC was probably not scheming either (thinking, “Great, I’ll fill the footprint with cheap blocks and save on expensive interior finishes by reducing living space—he wants it that way”). Instead, the GC fulfilled the customer’s requests for EH40 and calcium silicate brick, which in the “magical triangle” of parameters resulted in sacrificing the third parameter—the 425 size—and professionally increased the total wall thickness in one quantum leap to size 490. Up to this point, the OP clearly agrees with the GC. The GC then simply— and here I am convinced any assumption of ill intent is misplaced!—made a 50/50 choice to place the difference on the interior side rather than the exterior side. The OP would have preferred it on the exterior. That—and nothing more—is the heart of the issue. There is no reason here to escalate or settle a score. Clarify the misunderstanding, share a laugh, and shake hands—all can be done in a moment.
My expertise and experience as a neutral (and in serious cases, client-supporting) consultant led me to suggest to the OP that they could easily resolve the conflict they unknowingly caused by simply switching the structural wall assembler without any disadvantage (since for them, calcium silicate brick in this position—compared to aerated concrete, and unlike a lightweight hollow brick—offers no advantage but a significant U-value penalty). The OP, however, does not want this solution. Their feeling of being misled apparently matters more to them than a solution-oriented recognition that no one wants to do them harm, and that in my view, a better way out exists beyond any battle. There are plenty of experts so I don’t have to believe this without a second opinion. I do not accept the label of arrogance for this. Thank you for your post.
Unfortunately, you misunderstood me. Before signing the contract, the order was for a KfW 40 single-family house made from 17.5cm (7 inches) calcium silicate bricks plus insulation (I did not specify insulation thickness) plus 11.5cm (5 inches) facing bricks. I did not know how thick the insulation needed to be to meet KfW 40 standards. I left that to the GC. Subsequently, the GC created the colored drawings you now have. I trusted that these drawings already reflected a wall structure that complies with KfW 40 requirements and that we could rely on the indicated floor areas. I never wrote that the entire wall construction width must strictly be size 425 block. After signing, the GC sent me the information along with the building permit drawings that originally the wall was calculated using size 425 blocks but has now unfortunately increased by 6.5cm (3 inches):
“According to the requirements for KfW 40 and the preliminary specifications of our structural engineer, we extended the exterior walls from the original width of 42.5cm (17 inches) to now 49cm (19 inches). Also, in the ground floor, interior walls according to structural engineering were planned with a thickness of 17.5cm (7 inches). This leads to a slight loss of actual living space as well as small shifts in the interior walls according to structural engineering. However, this is absolutely necessary.”
Arauki11 schrieb:
@MachsSelbst
Assuming it is exactly as stated. What should the original poster do now, since it has already been proven that the general contractor deliberately and fraudulently treated him unfairly?
I have asked numerous times. What now, and I mean very specifically? He already knows he was deceived, so why is he still there?
Don’t just complain – please suggest a concrete, actionable alternative approach that will almost certainly succeed for the OP.
I am curious. I have no solution for him.As I already explained how I am going to proceed. Unfortunately, I don’t know any other way, I have to be honest about that. And yes, of course I will first approach the matter objectively and simply request that the walls be moved outward so that the contractually agreed room sizes at least roughly correspond again. By the way, I recalculated just now, finally with a clear head and some free time.
The originally planned living area was 164.84 m² (1774 sq ft) according to DIN standards.
The new living area is 155.27 m² (1671 sq ft) according to DIN standards.
The difference is a loss of 9.57 m² (103 sq ft).
ITSM2025 schrieb:
Thank you for your contribution.
Unfortunately, you misunderstood me. The contract before signing was for a KfW 40 single-family house made of 17.5cm (7 inches) sand-lime brick plus insulation (I did not specify any thickness here) plus 11.5cm (4.5 inches) facing brick. I did not know how thick the insulation needed to be to achieve KfW 40 standards. I left that to the general contractor. Subsequently, the contractor created the colorful drawings you have received. I trusted that these drawings already reflected the wall structure according to KfW 40 requirements and that we could rely on the stated floor areas. I never wrote that the total wall thickness should match a 42.5cm (17 inches) dimension exactly. After signing, the contractor sent me the building application drawings with the information that previously a 42.5cm (17 inches) wall structure was estimated, but this has now unfortunately increased by 6.5cm (2.5 inches):
"According to the requirements for KfW 40 and the preliminary information from our structural engineer, we have increased the exterior walls from the original width of 42.5cm to now 49cm (17 to 19.3 inches). Additionally, interior walls on the ground floor have been planned at 17.5cm (7 inches) according to structural engineering, which results in a slight reduction of the actual living area as well as minor shifts in the interior walls according to the structural plans. However, this is strictly necessary." Oh, I didn't know that the width was originally estimated at 42.5cm.
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