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!
Zubi123 schrieb:
Right side: 11.5 cm (4.5 inches) calcium silicate brick + cavity + 11.5 cm (4.5 inches) facing brick = 26 cm (10.2 inches)
Left side: this is basically the exterior wall of the house. Instead of the facing brick, an 11.5 cm (4.5 inches) calcium silicate brick is used.
What would you have expected here?Thanks, you're right. The air gap. I'm already too tired today.
G
Gerddieter16 Apr 2025 22:27I don’t see why there should be any discussion about this. The basis of the contract is the designs – the square meters are clearly shown there – by the way, the only measurement given. Wall thickness is determined by structural engineering – so there is no room for interpretation; in the end, the agreed square meters must be achieved.
To the original poster: no, this is not normal or standard practice. In our detailed planning, there were also slight deviations in square meter sizes compared to the contractually agreed plan, but these were only minor differences after the decimal point… sometimes a bit more, sometimes a bit less, and the total amount was nearly accurate – that would be considered normal.
However, it’s difficult to judge whether in your case this is intentional on the company’s part or simply the drafter’s mistake. Find out what’s going on, insist that the agreed square meters must be met, and see what happens.
To the original poster: no, this is not normal or standard practice. In our detailed planning, there were also slight deviations in square meter sizes compared to the contractually agreed plan, but these were only minor differences after the decimal point… sometimes a bit more, sometimes a bit less, and the total amount was nearly accurate – that would be considered normal.
However, it’s difficult to judge whether in your case this is intentional on the company’s part or simply the drafter’s mistake. Find out what’s going on, insist that the agreed square meters must be met, and see what happens.
M
MachsSelbst16 Apr 2025 23:22Hehe... stupidity working to one's own advantage, now that's a creative assumption. The builder charges extra for the thicker masonry, but any reductions in all trades that charge by square meter are simply ignored.
Screed, underfloor heating, included floor coverings, drywall ceiling on the upper floor. It all adds up when you calculate carefully with your subcontractors.
Screed, underfloor heating, included floor coverings, drywall ceiling on the upper floor. It all adds up when you calculate carefully with your subcontractors.
ITSM2025 schrieb:
I want to use KSL because of the sound insulation, which we unfortunately need at our location.Do you really think you don’t need it in this entire external wall construction? I’m just saying this to pull your leg. I have been in construction planning for four decades (mostly residential buildings, primarily single-family homes) professionally.
But I won’t say this again, so go ahead and make that mistake if you want.
https://www.instagram.com/11antgmxde/
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Gerddieter schrieb:
I don’t see why there should be any discussion. The basis of the contract is the plans – the square meters are clearly shown there – by the way, the only dimension specified. No, the exterior dimensions are also specified.
ITSM2025 schrieb:
“The contract only mentions this once: ‘Ground floor, as shown in the plans in terms of size.’” Which can just as well mean that the exterior dimensions shown in the plans must be adhered to. So there is plenty of room for interpretation.
In der Ruine17 Apr 2025 07:59Having built with aerated concrete myself, I can tell you to go for it. You will have insulation on the outside, brick cladding, and plaster on the inside. You won’t hear any noise through the walls. Sound usually comes through the window glass instead.
I believe @11ant knows what he’s talking about.
By the way, aerated concrete is available in different strength classes, making it either heavier and better at soundproofing, or lighter with improved insulation.
Just visit a model home park and take a look at houses built with aerated concrete and calcium silicate bricks. If needed, you could have your wife shout in front of the wall to test it.
I believe @11ant knows what he’s talking about.
By the way, aerated concrete is available in different strength classes, making it either heavier and better at soundproofing, or lighter with improved insulation.
Just visit a model home park and take a look at houses built with aerated concrete and calcium silicate bricks. If needed, you could have your wife shout in front of the wall to test it.
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