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How thick should a floor structure be in prefabricated concrete house without casting
Hello
I'm thinking about building a house with precast concrete elements. The only problem I've encountered is the intermediary floors between floor 1 and floor 2.
The issue is how to accommodate sewage, water-based underfloor heating, and ventilation system (FTX) in the floors.
I know the solution is to use intermediary floors with onsite pouring and support pillars from underneath until the floor has cured.
The reason I don't want to do this is due to the cost, as it is expensive and there might be simpler solutions.
My thoughts/own solutions are:
Solution 1: Solid floor/hollow core floor that is 5-20 CM thick with a subfloor (nivell, granab, subfloor) where sewage from floor 2 runs vertically under the floor and then a vertical opening and FTX for floor one is concealed, as well as openings for spotlights to floor 1 under the same floor, a so-called subfloor. In this way, I can accommodate sewage of 110 mm and 160 spiral duct for FTX.
Problem 1: How thick can it be? A 20CM concrete floor is not a problem but the height becomes! Then you would need a 1CM slope per meter for the sewage. Below I write from the top of the floor to the floor slab:
14 mm parquet
22 mm chipboard where underfloor heating is installed
160 mm FTX spiral duct for floor 1 and smaller 120 mm when it branches.
110 mm sewage pipe that needs a slope of 1 cm per meter
200 mm concrete floor
Result is 50 CM floor without sewage slope? Is this normal?
Solution 2: Timber joists that are built after the installation of exterior walls on floors 1&2 and interior walls for floor 1. Then I should be able to manage with a maximum 35 cm high intermediary floor?
Can you have exterior walls mounted on top of each other and not on the floor slab or do you cast a higher wall in the factory that you erect?
Can you have interior walls mounted on top of each other and not on the floor slab or do you cast a higher wall in the factory that you erect? Or can you only place interior walls on floor 1 and after the timber joists are done, build walls of wood and gypsum?
Can you then attach the timber joists to the walls on the inside?
I'm thinking about building a house with precast concrete elements. The only problem I've encountered is the intermediary floors between floor 1 and floor 2.
The issue is how to accommodate sewage, water-based underfloor heating, and ventilation system (FTX) in the floors.
I know the solution is to use intermediary floors with onsite pouring and support pillars from underneath until the floor has cured.
The reason I don't want to do this is due to the cost, as it is expensive and there might be simpler solutions.
My thoughts/own solutions are:
Solution 1: Solid floor/hollow core floor that is 5-20 CM thick with a subfloor (nivell, granab, subfloor) where sewage from floor 2 runs vertically under the floor and then a vertical opening and FTX for floor one is concealed, as well as openings for spotlights to floor 1 under the same floor, a so-called subfloor. In this way, I can accommodate sewage of 110 mm and 160 spiral duct for FTX.
Problem 1: How thick can it be? A 20CM concrete floor is not a problem but the height becomes! Then you would need a 1CM slope per meter for the sewage. Below I write from the top of the floor to the floor slab:
14 mm parquet
22 mm chipboard where underfloor heating is installed
160 mm FTX spiral duct for floor 1 and smaller 120 mm when it branches.
110 mm sewage pipe that needs a slope of 1 cm per meter
200 mm concrete floor
Result is 50 CM floor without sewage slope? Is this normal?
Solution 2: Timber joists that are built after the installation of exterior walls on floors 1&2 and interior walls for floor 1. Then I should be able to manage with a maximum 35 cm high intermediary floor?
Can you have exterior walls mounted on top of each other and not on the floor slab or do you cast a higher wall in the factory that you erect?
Can you have interior walls mounted on top of each other and not on the floor slab or do you cast a higher wall in the factory that you erect? Or can you only place interior walls on floor 1 and after the timber joists are done, build walls of wood and gypsum?
Can you then attach the timber joists to the walls on the inside?
Usually, when you have hollow core slabs, the installation runs are done under the slab and concealed by a dropped ceiling. Placing the walls on top of each other before the slab is not done because you don't have a slab to support them, preventing the walls from buckling at the joint. In this case, you would make the elements 2 stories high, which could increase costs in terms of transport and require a larger crane.
What does the roof slab look like, is it concrete too? I don't know anything about the floor plan or spans, but one alternative might be flat slabs where you can lay sewage, water, and parts of the ventilation.
What does the roof slab look like, is it concrete too? I don't know anything about the floor plan or spans, but one alternative might be flat slabs where you can lay sewage, water, and parts of the ventilation.
Doesn't absolutely have to be. Depending on the span and creative channel routing. The joist may probably end up around 200-250mm. Do you have any plans or sections of the house?
It completely depends on the prevailing conditions, so it's difficult to answer.
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