ᐅ Concrete slab – construction/insulation etc. – experiences, please!
Created on: 18 May 2016 21:47
C
Canca42
Hello to all home builders so far,
We plan to build a single-family house of 150 sqm (footprint approx. 91 sqm), one and a half stories high with a 180 cm (71 inch) knee wall on a slab-on-grade foundation.
We have received several offers from builders (wooden prefabricated houses)... we have decided that the house should meet KfW 55 standard. Now, regarding the construction of the slab-on-grade foundation, one building specification looks like this:
- Topsoil stripped off and stored at the side, max 30 cm (12 inches), foundations excavated
- Installation of up to 30 cm (12 inches) fill material under the slab with compaction, 2.5 m (8 feet) of fill added around the perimeter
- External foundations made of concrete C20/25 with reinforcement: 2 pieces of 8 mm (0.3 inch) rebar
- Slab-on-grade made of reinforced concrete C20/25, 20 cm (8 inches) thick, reinforced with 2 layers of steel mesh O188 A, protective foil laid underneath the slab
- Foundation grounding installed
- Sewer pipes for wastewater underneath the slab up to the outer edge of the foundation
- Base wall plaster ends at the top edge of the slab, front side of the slab insulated with rigid polystyrene foam board
That was offered at a relatively reasonable price. However, and we are aware of this, a few items are still missing, such as empty conduits, utility connections, etc. According to the builder, all this is possible at a low additional cost.
I am skeptical though... Another builder who constructs to KfW 40 standard says the slab-on-grade should be at least 25 to 30 cm (10 to 12 inches) thick, foundations made of steel fiber concrete, a layer of gravel under the slab, and Styrodur (extruded polystyrene) insulation under the slab.
Can anyone share insights or experiences on this? What additional costs can be expected in relation to the slab, for example, graveling the driveway for crane access — and what additional costs might come up?
Thanks in advance for your input.
We plan to build a single-family house of 150 sqm (footprint approx. 91 sqm), one and a half stories high with a 180 cm (71 inch) knee wall on a slab-on-grade foundation.
We have received several offers from builders (wooden prefabricated houses)... we have decided that the house should meet KfW 55 standard. Now, regarding the construction of the slab-on-grade foundation, one building specification looks like this:
- Topsoil stripped off and stored at the side, max 30 cm (12 inches), foundations excavated
- Installation of up to 30 cm (12 inches) fill material under the slab with compaction, 2.5 m (8 feet) of fill added around the perimeter
- External foundations made of concrete C20/25 with reinforcement: 2 pieces of 8 mm (0.3 inch) rebar
- Slab-on-grade made of reinforced concrete C20/25, 20 cm (8 inches) thick, reinforced with 2 layers of steel mesh O188 A, protective foil laid underneath the slab
- Foundation grounding installed
- Sewer pipes for wastewater underneath the slab up to the outer edge of the foundation
- Base wall plaster ends at the top edge of the slab, front side of the slab insulated with rigid polystyrene foam board
That was offered at a relatively reasonable price. However, and we are aware of this, a few items are still missing, such as empty conduits, utility connections, etc. According to the builder, all this is possible at a low additional cost.
I am skeptical though... Another builder who constructs to KfW 40 standard says the slab-on-grade should be at least 25 to 30 cm (10 to 12 inches) thick, foundations made of steel fiber concrete, a layer of gravel under the slab, and Styrodur (extruded polystyrene) insulation under the slab.
Can anyone share insights or experiences on this? What additional costs can be expected in relation to the slab, for example, graveling the driveway for crane access — and what additional costs might come up?
Thanks in advance for your input.
The thickness of the slab depends on the subsoil, region, the overall construction, and the loads that need to be supported.
Personally, I find a building variant without a basement quite pointless... but with slabs without a basement, special attention must be paid to the frost protection strip or a frost-resistant subsoil.
The floor structure generally includes insulation. It makes sense to install a perimeter strip and insulation beneath the slab. The junction with the wall construction then becomes less relevant.
Personally, I find a building variant without a basement quite pointless... but with slabs without a basement, special attention must be paid to the frost protection strip or a frost-resistant subsoil.
The floor structure generally includes insulation. It makes sense to install a perimeter strip and insulation beneath the slab. The junction with the wall construction then becomes less relevant.
BauRoman schrieb:
Personally, I find a building option without a basement completely pointless... Why, because a slab with a basement is automatically at frost-free depth?
Technically, this has only a minor impact. Except that the foundation slab is located in a frost-protected zone and the ground temperature at this depth is much more stable.
Personally, I cannot imagine a house without a basement.
1) I would miss all the storage space. From plants that need to be stored in winter, to winter and summer clothing, as well as sports, leisure, and vehicle accessories.
2) I would even miss having a small workshop or hobby room.
3) The entire relocation of the laundry room would have to be somewhere on the upper floors, along with the heating, water, and electrical systems.
4) Storing wine and food supplies at a constant, cool temperature without electricity costs is also difficult without a basement.
--> Conclusion:
I could not do without a basement.
Personally, I cannot imagine a house without a basement.
1) I would miss all the storage space. From plants that need to be stored in winter, to winter and summer clothing, as well as sports, leisure, and vehicle accessories.
2) I would even miss having a small workshop or hobby room.
3) The entire relocation of the laundry room would have to be somewhere on the upper floors, along with the heating, water, and electrical systems.
4) Storing wine and food supplies at a constant, cool temperature without electricity costs is also difficult without a basement.
--> Conclusion:
I could not do without a basement.
Hello everyone,
due to the geotechnical survey, we want/need to build without a basement because otherwise a waterproof concrete shell and additional measures to protect the surrounding buildings would be necessary. It will be an age-friendly timber frame house without steps, featuring a single-pitch roof and built to KfW 40+ standard. There will be a small apartment on the upper floor. One supplier offers an uninsulated concrete slab with foundations, on top of which is a screed with 250 cm (10 inches), including 160 mm (6 inches) of insulation. What do you think about this construction method?
due to the geotechnical survey, we want/need to build without a basement because otherwise a waterproof concrete shell and additional measures to protect the surrounding buildings would be necessary. It will be an age-friendly timber frame house without steps, featuring a single-pitch roof and built to KfW 40+ standard. There will be a small apartment on the upper floor. One supplier offers an uninsulated concrete slab with foundations, on top of which is a screed with 250 cm (10 inches), including 160 mm (6 inches) of insulation. What do you think about this construction method?
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