Hello everyone,
I am planning to buy a house with a garden that is terraced using basalt stones.
During the viewing, I noticed one of the stones shown in the photos has a crack approximately 3.5 cm (1.4 inches) wide, essentially splitting it. I was told that basalt stone usually does not crack or break.
Therefore, I am asking you experienced experts whether this crack is a cause for concern or if it is purely cosmetic.
Thank you for your knowledge.
Best regards,
Fred
I am planning to buy a house with a garden that is terraced using basalt stones.
During the viewing, I noticed one of the stones shown in the photos has a crack approximately 3.5 cm (1.4 inches) wide, essentially splitting it. I was told that basalt stone usually does not crack or break.
Therefore, I am asking you experienced experts whether this crack is a cause for concern or if it is purely cosmetic.
Thank you for your knowledge.
Best regards,
Fred
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nordanney18 Apr 2026 14:44Fred schrieb:
No idea if the stone supports the soil above and next to it, and if the crack might cause instability You’re just imagining things ;-)
Fred schrieb:
which shifts sideways along the width of the crack toward the house wall, pushing the stones there against the facade. It does not shift by itself.
Fred schrieb:
From the previous answers, I gather that this does not seem to be the case. Yes. However, if you find cracks in the soil or on the terrace, then you should be concerned (for example, with a house built over old mining areas). Otherwise, it’s really just a broken stone if nothing else is visible (at least not in the pictures).
ateliersiegel19 Apr 2026 14:40It seems somewhat inappropriate to mock a question like that. There is a common saying: "There are no stupid questions."
There could very well be a cause for a cracked stone that might also have consequences for the house. I am not a stone expert, but I cannot think of any reason other than that it probably cracked "on its own." My impression is that this crack is relatively new. There is nothing inside the crack, even though the stone has presumably been there for a long time. Basalt is found, as far as I know, in areas where there has been or still is volcanic activity. ... in any case, the crack has something interesting about it.
There could very well be a cause for a cracked stone that might also have consequences for the house. I am not a stone expert, but I cannot think of any reason other than that it probably cracked "on its own." My impression is that this crack is relatively new. There is nothing inside the crack, even though the stone has presumably been there for a long time. Basalt is found, as far as I know, in areas where there has been or still is volcanic activity. ... in any case, the crack has something interesting about it.
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nordanney19 Apr 2026 18:32By the way, an AI gives the same answers:
“This is a fascinating sight! First of all: The statement that basalt stones ‘usually don’t crack’ is only partly true. Although basalt is extremely hard and pressure-resistant, it has a natural property known as columnar basalt. When lava cools, it tends to crack in regular (often hexagonal) patterns.
To reassure you: In most cases, such a crack in a garden wall is purely cosmetic. Here are the details for assessment:
Why the stone has split
A crack this wide (3.5 cm (1.4 inches)) rarely appears suddenly in natural stone. Possible causes include:
Frost damage: This is the most likely cause. Water seeps into tiny natural capillaries or hairline cracks. When it freezes, it expands and exerts enormous pressure. Over decades, this process ‘works’ the stone apart.
Natural bedding planes: The stone may have had an invisible weak point (a so-called vein) from the start, which has now become visible due to its own weight or soil settlement.
Root pressure: If soil accumulates in the crack and plants (or even shrubs) take root there, their roots can gradually force the stone apart like a wedge.
Is this a cause for concern?
For the structural integrity of the building, this stone is completely irrelevant. It is part of the garden design and only supports the small area of the steps or planting bed.”
“This is a fascinating sight! First of all: The statement that basalt stones ‘usually don’t crack’ is only partly true. Although basalt is extremely hard and pressure-resistant, it has a natural property known as columnar basalt. When lava cools, it tends to crack in regular (often hexagonal) patterns.
To reassure you: In most cases, such a crack in a garden wall is purely cosmetic. Here are the details for assessment:
Why the stone has split
A crack this wide (3.5 cm (1.4 inches)) rarely appears suddenly in natural stone. Possible causes include:
Frost damage: This is the most likely cause. Water seeps into tiny natural capillaries or hairline cracks. When it freezes, it expands and exerts enormous pressure. Over decades, this process ‘works’ the stone apart.
Natural bedding planes: The stone may have had an invisible weak point (a so-called vein) from the start, which has now become visible due to its own weight or soil settlement.
Root pressure: If soil accumulates in the crack and plants (or even shrubs) take root there, their roots can gradually force the stone apart like a wedge.
Is this a cause for concern?
For the structural integrity of the building, this stone is completely irrelevant. It is part of the garden design and only supports the small area of the steps or planting bed.”