Hello everyone,
We are about to sign our contract. It contains a passage which I will quote:
"Excluded from the warranty are ground settlements in the areas of workspaces, as long as they concern backfilled external areas, as well as shrinkage cracks, especially in the attic, that have no significance or consequences for proper execution. Shrinkage cracks are caused by different expansion behavior of various materials. The contractor recommends covering these during the painting work."
I understand that cracks can occur during house construction. This seems to be normal.
We are building with waterproof concrete, quality C25/30 (according to the scope of work).
During the contract review, I received a note from an expert of the Building Owners’ Protection Association, stating that shrinkage cracks up to 0.2 mm (0.008 inches) are normal. However, he could not provide any evidence for this.
Based on this, I asked my construction company to change the wording to "as well as shrinkage cracks up to 0.2 mm (0.008 inches), especially ...". The construction company, in turn, contacted a renowned TÜV expert, who informed them that there is no fixed size or width defined for shrinkage cracks. Therefore, the construction company does not want to change this passage.
I am a layperson and am faced here with two different expert opinions.
Could any of the professionals here tell me if there is a standard / DIN / regulation regarding the maximum permissible crack width and where I can find it?
I have a good relationship with the construction company and only want to challenge it if there are actually solid requirements regarding this. Otherwise, I will rely on the construction company’s advice and good reputation.
We are about to sign our contract. It contains a passage which I will quote:
"Excluded from the warranty are ground settlements in the areas of workspaces, as long as they concern backfilled external areas, as well as shrinkage cracks, especially in the attic, that have no significance or consequences for proper execution. Shrinkage cracks are caused by different expansion behavior of various materials. The contractor recommends covering these during the painting work."
I understand that cracks can occur during house construction. This seems to be normal.
We are building with waterproof concrete, quality C25/30 (according to the scope of work).
During the contract review, I received a note from an expert of the Building Owners’ Protection Association, stating that shrinkage cracks up to 0.2 mm (0.008 inches) are normal. However, he could not provide any evidence for this.
Based on this, I asked my construction company to change the wording to "as well as shrinkage cracks up to 0.2 mm (0.008 inches), especially ...". The construction company, in turn, contacted a renowned TÜV expert, who informed them that there is no fixed size or width defined for shrinkage cracks. Therefore, the construction company does not want to change this passage.
I am a layperson and am faced here with two different expert opinions.
Could any of the professionals here tell me if there is a standard / DIN / regulation regarding the maximum permissible crack width and where I can find it?
I have a good relationship with the construction company and only want to challenge it if there are actually solid requirements regarding this. Otherwise, I will rely on the construction company’s advice and good reputation.
Hausverkäufer03 Apr 2014 15:42Concrete in the attic? I think there might be a misunderstanding!
If you have a good relationship with the construction company, just ask them which shrinkage cracks they mean. I would guess it’s the joint between the drywall ceiling and the exterior masonry. This joint will only become stable very late and any acrylic sealants applied during construction may crack again. However, this is completely different from the quality or crack class of a waterproof concrete basement!
If the specifications are not precise enough, I would recommend simply changing them. If that is not possible, you could add it as an additional agreement to the contract.
If you have a good relationship with the construction company, just ask them which shrinkage cracks they mean. I would guess it’s the joint between the drywall ceiling and the exterior masonry. This joint will only become stable very late and any acrylic sealants applied during construction may crack again. However, this is completely different from the quality or crack class of a waterproof concrete basement!
If the specifications are not precise enough, I would recommend simply changing them. If that is not possible, you could add it as an additional agreement to the contract.
Hello house seller,
You are absolutely right. Sometimes you just sit in front of it and can’t see the forest for the trees.
Of course, the top floor has a wooden beam ceiling.
The ground floor ceiling is a “reinforced concrete slab according to structural requirements as a system slab with a cast-in-place concrete layer.”
The walls are made of Ytong blocks.
Regardless, the question remains which shrinkage cracks are acceptable.
@Bauexperte
Do the shrinkage crack dimensions you posted also apply to other materials, or are Ytong blocks, for example, also prone to shrinkage cracks?
Somehow I’m having trouble understanding this topic.
You are absolutely right. Sometimes you just sit in front of it and can’t see the forest for the trees.
Of course, the top floor has a wooden beam ceiling.
The ground floor ceiling is a “reinforced concrete slab according to structural requirements as a system slab with a cast-in-place concrete layer.”
The walls are made of Ytong blocks.
Regardless, the question remains which shrinkage cracks are acceptable.
@Bauexperte
Do the shrinkage crack dimensions you posted also apply to other materials, or are Ytong blocks, for example, also prone to shrinkage cracks?
Somehow I’m having trouble understanding this topic.
Hausverkäufer04 Apr 2014 10:04Shrinkage cracks can occur whenever the material changes due to the drying process (shrinks). This is normal.
When a damp plaster surface is joined to a drywall panel, a small gap forms. However, the plaster surface continues to dry and changes its dimensions. The gap becomes larger. If something was previously placed in this gap, it will no longer completely fill it. A shrinkage crack has formed. Whether this crack is 2 or 3 mm (0.08 or 0.12 inches) wide is actually secondary. It simply needs to be sealed again. Ask people you know who have built with bricks and mortar and have lived in the house for at least a year.
You will hardly find a construction company willing to guarantee that this joint or gap will not open, because it inevitably will. Any promises that this will not happen and all the perfect designs claiming to prevent it are worthless. Many drywall installers have sworn to me that they always build so the joint does not open—but none have succeeded. The simplest solution is a scrape cut in the plaster to keep the joint open. This should then be sealed very late in the process (during painting) with acrylic. Any joint that reopens later can then be permanently sealed with acrylic.
Please also pay attention to the joints where the floor coverings meet. The screed will also change during drying, and the baseboards will need to be redone later. Of course, you can agree for an additional fee that the contractor will re-seal all joints and adjust the baseboards after a defined period. However, this will almost certainly not come with a warranty. It will save you from doing it yourself, though.
There are also permissible widths for shrinkage cracks in plaster or masonry. If you want to discuss all this with your building partner and try to change contracts accordingly, it will become very complicated, and your building partner will become very suspicious. The consequence might be that they decide against the contract because they don’t want to spend their time on "endless debates about potentially occurring cracks and their allowable widths."
It is best to require that your builder constructs your house according to the recognized rules of technology and the applicable DIN standards. In case of damage, it will then be clearly defined what counts as a defect and what does not. You can rely on this and, if necessary, dispute it. Furthermore, the roof frame should be made of engineered solid timber (construction-grade timber, KVH) and the drywall ceiling battens should be aluminum profiles. (This should actually be stated in every contract.)
When a damp plaster surface is joined to a drywall panel, a small gap forms. However, the plaster surface continues to dry and changes its dimensions. The gap becomes larger. If something was previously placed in this gap, it will no longer completely fill it. A shrinkage crack has formed. Whether this crack is 2 or 3 mm (0.08 or 0.12 inches) wide is actually secondary. It simply needs to be sealed again. Ask people you know who have built with bricks and mortar and have lived in the house for at least a year.
You will hardly find a construction company willing to guarantee that this joint or gap will not open, because it inevitably will. Any promises that this will not happen and all the perfect designs claiming to prevent it are worthless. Many drywall installers have sworn to me that they always build so the joint does not open—but none have succeeded. The simplest solution is a scrape cut in the plaster to keep the joint open. This should then be sealed very late in the process (during painting) with acrylic. Any joint that reopens later can then be permanently sealed with acrylic.
Please also pay attention to the joints where the floor coverings meet. The screed will also change during drying, and the baseboards will need to be redone later. Of course, you can agree for an additional fee that the contractor will re-seal all joints and adjust the baseboards after a defined period. However, this will almost certainly not come with a warranty. It will save you from doing it yourself, though.
There are also permissible widths for shrinkage cracks in plaster or masonry. If you want to discuss all this with your building partner and try to change contracts accordingly, it will become very complicated, and your building partner will become very suspicious. The consequence might be that they decide against the contract because they don’t want to spend their time on "endless debates about potentially occurring cracks and their allowable widths."
It is best to require that your builder constructs your house according to the recognized rules of technology and the applicable DIN standards. In case of damage, it will then be clearly defined what counts as a defect and what does not. You can rely on this and, if necessary, dispute it. Furthermore, the roof frame should be made of engineered solid timber (construction-grade timber, KVH) and the drywall ceiling battens should be aluminum profiles. (This should actually be stated in every contract.)
Hausverkäufer04 Apr 2014 10:18I forgot to mention that cracks in the aerated concrete blocks are not acceptable! This material must be installed crack-free. Otherwise, there will be serious structural issues!
B
Bauexperte4 Apr 2014 10:53Hello,
So it’s not a “modern” build in the sense of the Brussels planners after all; I was already wondering about that. There have been single-family homes made entirely of concrete for a long time; this includes the attic as well. These also don’t necessarily feel like a “creaky house.”
If significant cracks appear when using aerated concrete, clay blocks (Poroton), or sand-lime bricks, errors were already made in the foundation of the construction project. Both load-dependent and load-independent causes can be involved; explaining all of this in detail won’t help you much, as it can only be described very technically. Try searching the web at xxx.DIN-Bauportal.de/Index.php?mid=121; there you’ll find what I think is a layman-friendly explanation of how and why cracks occur in masonry.
I can tell from your question that you’ve been talking too much with the representative from the Homeowners’ Protection Association. This ultimately causes exactly what I don’t appreciate about their services. As a client, you become more uncertain than enlightened—and you pay for that.
**The causes that lead to cracks in ceilings and walls are very complex. Cracks in common building materials are often unavoidable. Therefore, the mere presence of a visible crack in a component does not automatically imply that there is a defect or damage. A completely crack-free surface cannot generally—or only to a limited extent—be achieved. This applies especially to mineral exterior plasters. The plaster standard (DIN 18550-2) states that “isolated hairline cracks” (defined as crack width < 0.2 mm (0.008 inches)) are not considered defective since they do not impair the technical properties of the plaster. The decisive criterion for whether cracks in the plaster are acceptable is therefore not their mere existence, but rather the impact of the cracks on the required optical and technical functions of the plaster.
**Source: Gänssmantel, publicly sworn and appointed expert
As user "Hausverkäufer" rightly pointed out, your builder will hardly agree to a verification in the contract. This is not necessary as long as the following sentence is included in the general building terms or as an addendum to the contract: “The contractor agrees to carry out the construction project in accordance with the currently valid rules of technology.” This still does not protect your building from cracks—it can’t—but it obliges your builder to carry out repairs for cracks wider than 0.2 mm (0.008 inches).
Basically, previous builders were right when they said that a new build needs time, and a shell should be allowed to stand for a while before interior work begins. Nowadays, with many clients wanting to move in as quickly as possible after signing the contract, this has put pressure on the building materials and prompted other reactions — the material always tries to relieve stress through movement. If this movement is not possible (which is hardly feasible), a restriction occurs and external forces (loads) build up stresses inside the material. This leads to cracks, which—as the DIN standard shows—are allowed within narrow tolerances because they cannot be prevented.
Best regards, Bauexperte
f-pNo schrieb:
Of course, the attic has a wooden beam ceiling.
The ceiling on the ground floor will be "a reinforced concrete slab according to structural requirements, as a system slab with an in-situ concrete layer." The walls will be made of Ytong blocks.
So it’s not a “modern” build in the sense of the Brussels planners after all; I was already wondering about that. There have been single-family homes made entirely of concrete for a long time; this includes the attic as well. These also don’t necessarily feel like a “creaky house.”
f-pNo schrieb:
Do the shrinkage crack dimensions you posted also apply to other materials, or are Ytong blocks, for example, also prone to shrinkage cracks?
If significant cracks appear when using aerated concrete, clay blocks (Poroton), or sand-lime bricks, errors were already made in the foundation of the construction project. Both load-dependent and load-independent causes can be involved; explaining all of this in detail won’t help you much, as it can only be described very technically. Try searching the web at xxx.DIN-Bauportal.de/Index.php?mid=121; there you’ll find what I think is a layman-friendly explanation of how and why cracks occur in masonry.
f-pNo schrieb:
f-pNo schrieb:
Somehow, I can’t get my head around this topic .
I can tell from your question that you’ve been talking too much with the representative from the Homeowners’ Protection Association. This ultimately causes exactly what I don’t appreciate about their services. As a client, you become more uncertain than enlightened—and you pay for that.
**The causes that lead to cracks in ceilings and walls are very complex. Cracks in common building materials are often unavoidable. Therefore, the mere presence of a visible crack in a component does not automatically imply that there is a defect or damage. A completely crack-free surface cannot generally—or only to a limited extent—be achieved. This applies especially to mineral exterior plasters. The plaster standard (DIN 18550-2) states that “isolated hairline cracks” (defined as crack width < 0.2 mm (0.008 inches)) are not considered defective since they do not impair the technical properties of the plaster. The decisive criterion for whether cracks in the plaster are acceptable is therefore not their mere existence, but rather the impact of the cracks on the required optical and technical functions of the plaster.
**Source: Gänssmantel, publicly sworn and appointed expert
As user "Hausverkäufer" rightly pointed out, your builder will hardly agree to a verification in the contract. This is not necessary as long as the following sentence is included in the general building terms or as an addendum to the contract: “The contractor agrees to carry out the construction project in accordance with the currently valid rules of technology.” This still does not protect your building from cracks—it can’t—but it obliges your builder to carry out repairs for cracks wider than 0.2 mm (0.008 inches).
Basically, previous builders were right when they said that a new build needs time, and a shell should be allowed to stand for a while before interior work begins. Nowadays, with many clients wanting to move in as quickly as possible after signing the contract, this has put pressure on the building materials and prompted other reactions — the material always tries to relieve stress through movement. If this movement is not possible (which is hardly feasible), a restriction occurs and external forces (loads) build up stresses inside the material. This leads to cracks, which—as the DIN standard shows—are allowed within narrow tolerances because they cannot be prevented.
Best regards, Bauexperte
Hausverkäufer04 Apr 2014 11:02Hello building expert.
Where has the link to the PDF from Gänssmantel gone? Are links not allowed in this forum?
Greetings from Berlin
Where has the link to the PDF from Gänssmantel gone? Are links not allowed in this forum?
Greetings from Berlin
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