ᐅ Living area approximately 8 m² smaller in the permit drawings compared to the design (general contractor)
Created on: 16 Apr 2025 11:23
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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!
In the preliminary draft, it appears that the interior walls are 11 cm (4.3 inches) thick instead of 17 cm (6.7 inches). Do you see it the same way?
That would roughly make a difference of about 1.5 m² (16 ft²).
The interior wall between the living room and dining area also seems to have shifted slightly upward, which reduces the size of the living room, while the dining area remains almost the same despite thicker exterior walls (if I have identified and calculated it correctly).
That would roughly make a difference of about 1.5 m² (16 ft²).
The interior wall between the living room and dining area also seems to have shifted slightly upward, which reduces the size of the living room, while the dining area remains almost the same despite thicker exterior walls (if I have identified and calculated it correctly).
ITSM2025 schrieb:
I’ve simply uploaded the draft and the drawing for the building permit application here. Maybe it will make clearer what I mean. [ / ] Could these now possibly work? Unfortunately, I couldn’t crop the more detailed drawing any better. Above all, you shouldn’t cut out the upper floor (OG), attic (DG), and for the building permit also the section.
ITSM2025 schrieb:
By preliminary draft I mean the design that is typically created with a general contractor (GC) before anything is signed. For example, this one didn’t have exact room dimensions, only what you can see attached. Ah, a pre-signing design. Thanks! – I finally understand how homeowners come to speak of a “preliminary draft” when there are obviously no such drafts in the planning. The term actually refers to a scale sketch to show how the room program translates into a concrete building volume, for discussion between the homeowner and the architect or for the preliminary building inquiry with the planning authority. So, the design during service phase 2 (which doesn’t exist with the GC drafter).
ypg schrieb:
However, I have to say from memory, we upgraded to KfW70 back then, and the exterior insulation was increased from 12 to 14 or 16 cm (5 to 6 or 6.3 inches), but on the outside. The inside remained the same. A one-and-a-half-layer assembly (construction masonry - insulation - render) is the usual approach.
ypg schrieb:
Again: Check the scope of services description and the contract, which we don’t know. If the scope of services states a wall assembly that doesn’t meet the desired U-value, it won’t help here. “Wash me, but don’t get me wet” (i.e., replace aerated concrete in the structural masonry shell with calcium silicate brick without making it thicker or changing the insulation) can’t work. If the homeowner then orders the GC with “EH40 rules,” a more extensive overall wall assembly is inevitable. Without the additional instruction “Please apply the increased thickness fully on the outside,” the result is exactly what the original poster here is complaining about.
Musketier schrieb:
In the preliminary draft, it looks like the interior walls are 8 cm (3 inches) instead of 17 cm (7 inches). Do you see it that way too? The interior walls look unrealistically thin, yes.
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Arauki11 schrieb:
What does the general contractor say about your specific inquiry? That would be the first step, so there’s no need to speculate here.
They should be able to explain whether this is acceptable or not, but this inquiry should definitely be made first. Due to the planner being on holiday, who we had clarified everything with so far, there has been no response yet. With the drawings for the building permit / planning permission, only the following was provided:
“According to the requirements for KfW40 and the preliminary information from our structural engineer, we have increased the thickness of the exterior walls from originally 42.5 cm (17 inches) to now 49 cm (19 inches). Additionally, interior walls on the ground floor have been planned at 17.5 cm (7 inches) thickness based on structural engineering requirements. This results in a slight reduction of the actual living space, as well as minor shifts of the interior walls according to the structural calculations. However, this is strictly necessary.
We have also extended the width of the captain’s gable free of charge, from originally 3.49 m (11 ft 5 in) to now 3.74 m (12 ft 3 in). The reason for this is that the two supports on the ground floor must be approximately 55 cm (22 inches) wide for structural reasons. To ensure that the entrance area does not appear cramped or small, while at the same time allowing the supports to look substantial and visually appealing, we decided to increase the width.”
I will know more next week.
ITSM2025 schrieb:
This is a design typically created with a general contractor (GC) before signing anything... It’s not a standard floor plan from a catalog since we had already sketched everything ourselves in advance (only with desired room sizes, without exact measurements) and sent it to the GC, who then professionally redrew the design. So on the left is the design drawn by the "GC"? This is not a production house, but a design redrawn by the GC in a clean quality to serve as the basis for the contract. At first glance, it’s clear that this floor plan has little in common with an architect’s floor plan.
I put GC in quotation marks because the GC is a company. The seller (not the architect) likely created a neat design using software, and then after the contract is signed, the architect takes that design and adjusts it. That’s what happened here, and now you’re surprised that the modifications seem to work against you because you keep calculating how high the square meters are.
Basically, everything is understandable. It’s just that you are now overreacting a bit more than expected: just tell the GC that the architect should please correct the exterior walls—the thicker walls—to be positioned outward compared to the sketch. If the plot is large enough and nothing is right at the boundary lines, this should be feasible. That part of the house remains the same for the GC. You have a fixed price.
But as mentioned before: check what the contract says!
So, what I’m really trying to get at: Should I raise this issue with the general contractor now, or is this just "how it is" and something I have to accept? The contract only mentions this once in relation to possible implications: "Ground floor, sized as shown in the drawings, finished according to the specifications in the construction description," and the same applies to the attic. As I said, at that time, we only had the colored drawings. The more detailed drawing was only provided after the architects’ service was commissioned. Additionally, further back in the scope of work description, it states, "The dimensions included in the construction drawings and the construction description are approximate values. In case of discrepancies between the construction plans and the construction description, the construction description takes precedence; for discrepancies in the dimensions, the execution plans are authoritative."
There is nothing else relevant here that could apply.
There is nothing else relevant here that could apply.
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