ᐅ Concrete slab on a slight slope for a single-family house with a basement
Created on: 6 Sep 2018 08:04
M
Medis
Hello everyone
I want to build a single-family house without a basement. Planned structure:
- Crushed stone, compacted. Slope evened out with topsoil and crushed stone.
- Styrodur (continuous thermal insulation)
- Concrete slab 25 cm (10 inches) thick (without strip footings)
The house will be built on a slight slope. Slope across the house width (10 m / 33 feet) is about 90 cm (35 inches), with the first half of the house on a level section and the slope starting on the second half.
I’m concerned about the concrete slab. Can the compacted crushed stone settle over time, causing the soil/crushed stone under the house to “shift” or move? Or is compacted crushed stone sufficient/okay? Should strip footings maybe be used instead, or are there other ideas?
I would appreciate your opinions, possibly a suggestion on how to improve the design. Thank you very much
Best regards
I want to build a single-family house without a basement. Planned structure:
- Crushed stone, compacted. Slope evened out with topsoil and crushed stone.
- Styrodur (continuous thermal insulation)
- Concrete slab 25 cm (10 inches) thick (without strip footings)
The house will be built on a slight slope. Slope across the house width (10 m / 33 feet) is about 90 cm (35 inches), with the first half of the house on a level section and the slope starting on the second half.
I’m concerned about the concrete slab. Can the compacted crushed stone settle over time, causing the soil/crushed stone under the house to “shift” or move? Or is compacted crushed stone sufficient/okay? Should strip footings maybe be used instead, or are there other ideas?
I would appreciate your opinions, possibly a suggestion on how to improve the design. Thank you very much
Best regards
The structural engineer determines the thickness of the slab and the foundation.
The insulation is specified by the thermal protection certificate.
Compacted topsoil is not suitable. For backfilling, use a mineral aggregate mix 0/32; possibly the bottom layer can be 0/45. Compact in layers, better once more than too little. If you want to be sure, have the compaction tested with plate load tests.
Everything you fill in must be properly secured. This is done with the landscaping through grass areas, terraces, walls, etc.
The insulation is specified by the thermal protection certificate.
Compacted topsoil is not suitable. For backfilling, use a mineral aggregate mix 0/32; possibly the bottom layer can be 0/45. Compact in layers, better once more than too little. If you want to be sure, have the compaction tested with plate load tests.
Everything you fill in must be properly secured. This is done with the landscaping through grass areas, terraces, walls, etc.
Medis schrieb:
Whoever only wants to explain jokes and nonsense should rather keep silent. Who made jokes here?
Sorry, your tone (and also your spelling) is clearly inappropriate.
No one here can provide you with well-founded information. Anyone who would do so would do you a disservice. This is not a place for brainstorming; there are regulations and requirements that must be followed.
Nothing else.
W
WilhelmRo6 Sep 2018 14:32bortel schrieb:
It's really unbelievable what some people try to come up with on their own here?! A question about practical experience was asked.
There are no stupid questions, only stupid answers!
At first, I replied via private message since the question was posted in a different thread, and I didn’t want to "hijack" it. Here is the response again for everyone to read publicly:
Compaction can only be understood as the material becoming "saturated" under vertical pressure, assuming it cannot move sideways anymore. A substrate that is not laterally confined cannot be stably compacted. Stacking layers on a sloped base simply won’t work; you will have to create "steps."
From the perspective of the initial responders, it was probably the original poster. It is, of course, an amusing idea to use a wedge-shaped cushion—which the house would slide down on perfectly well—as a "foundation." However, this concept likely stems from an underdeveloped spatial understanding and was not meant primarily to tease those following the discussion.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
Medis schrieb:
Can compacted gravel eventually give way, causing the soil/gravel beneath the house to "float away"?
Compaction can only be understood as the material becoming "saturated" under vertical pressure, assuming it cannot move sideways anymore. A substrate that is not laterally confined cannot be stably compacted. Stacking layers on a sloped base simply won’t work; you will have to create "steps."
Climbee schrieb:
Who made jokes here?
From the perspective of the initial responders, it was probably the original poster. It is, of course, an amusing idea to use a wedge-shaped cushion—which the house would slide down on perfectly well—as a "foundation." However, this concept likely stems from an underdeveloped spatial understanding and was not meant primarily to tease those following the discussion.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
Since most people here do not dig or design their own foundation but leave it to a professional, experience tends to be limited—especially considering that experience usually needs to be gained through multiple cases, allowing for comparison.
The first page already stated it correctly: a geotechnical report by a geologist, combined with the expertise of a structural engineer... that is the successful approach.
The first page already stated it correctly: a geotechnical report by a geologist, combined with the expertise of a structural engineer... that is the successful approach.
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