ᐅ Expanded polystyrene (EPS) granules for varying structural floor slab heights
Created on: 4 Mar 2021 10:34
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Eyko123
Hello,
we are currently planning the ground floor floor construction in a single-family house that is being renovated. The house is only partially basemented, and the structural height in the basemented rooms is higher than in the non-basemented rooms. If we now install expanded polystyrene granulate (then underfloor heating and screed), there will be 12cm (5 inches) of granulate in the basemented rooms and 28cm (11 inches) in the non-basemented rooms. Can anyone tell me if this might cause problems because the granulate could settle unevenly over the years? Would it be an alternative to raise the non-basemented rooms with expanded polystyrene granulate to the same level as the other rooms and then install insulation boards everywhere?
Thank you! 🙂
we are currently planning the ground floor floor construction in a single-family house that is being renovated. The house is only partially basemented, and the structural height in the basemented rooms is higher than in the non-basemented rooms. If we now install expanded polystyrene granulate (then underfloor heating and screed), there will be 12cm (5 inches) of granulate in the basemented rooms and 28cm (11 inches) in the non-basemented rooms. Can anyone tell me if this might cause problems because the granulate could settle unevenly over the years? Would it be an alternative to raise the non-basemented rooms with expanded polystyrene granulate to the same level as the other rooms and then install insulation boards everywhere?
Thank you! 🙂
Eyko123 schrieb:
What kind of mat would that be? So if the screed thickness is around 7cm (3 inches), would it be located roughly halfway up within the screed?
Good point about the anhydrite, thanks. Unfortunately, I’m not sure either. Our screed installer placed them at critical spots. It was a plastic mesh fabric—I don’t really know the exact name. He laid it on top of the underfloor heating pipes.
pagoni2020 schrieb:
A silly question: I can’t really tell from the pictures what’s happening next to it.
Couldn’t you remove this raised section entirely, so both parts are on the same bottom level?
Looks in the picture like there are hollow bricks or something similar on the floor... As described, that’s the basement ceiling. I wouldn’t chisel anything off there.
P
pagoni20205 Mar 2021 10:54Okay..... otherwise you have direct access to the wine cellar, so why not?? 😀 😀
Then I would probably create the same level in a simple and inexpensive way. The question is whether you want to do it yourself; if so, I would do something that suits my own skills. Basically, you could put anything in there, even loose gravel or something like that, since the main goal is just to reach the actual floor level. From there, the real floor structure with insulation and so on begins.
Alternatively, you could install a joist layer with an inexpensive filler material in between and then cover it with OSB or Fermacell or similar.
I would reconsider filling the entire 28cm (11 inches) with high-quality/expensive insulation, or it would depend on the amount and cost. After a certain thickness, additional insulation doesn’t provide much extra benefit.
The owner of my former construction company once told me, regarding a similar question about insulating/filling the spaces between the joists, to simply fill them with sand. I ended up using expensive cork granules, which worked well, but somehow I think sand would have worked just as well for much less money.
Then I would probably create the same level in a simple and inexpensive way. The question is whether you want to do it yourself; if so, I would do something that suits my own skills. Basically, you could put anything in there, even loose gravel or something like that, since the main goal is just to reach the actual floor level. From there, the real floor structure with insulation and so on begins.
Alternatively, you could install a joist layer with an inexpensive filler material in between and then cover it with OSB or Fermacell or similar.
I would reconsider filling the entire 28cm (11 inches) with high-quality/expensive insulation, or it would depend on the amount and cost. After a certain thickness, additional insulation doesn’t provide much extra benefit.
The owner of my former construction company once told me, regarding a similar question about insulating/filling the spaces between the joists, to simply fill them with sand. I ended up using expensive cork granules, which worked well, but somehow I think sand would have worked just as well for much less money.
Regarding the question about doing it yourself:
I really enjoyed demolishing everything myself; that was genuinely fun. However, I prefer to leave the new installation to the professionals. I just ask questions and appreciate all the answers here because I want to understand it myself, so I can follow along when the screed company suggests this or that.
There is even a wine cellar, but it is located separately in the garden.
I really enjoyed demolishing everything myself; that was genuinely fun. However, I prefer to leave the new installation to the professionals. I just ask questions and appreciate all the answers here because I want to understand it myself, so I can follow along when the screed company suggests this or that.
There is even a wine cellar, but it is located separately in the garden.
P
pagoni20205 Mar 2021 12:22I think you could do that, but you would have a lot of moisture in the ground, and the drying process could take a very long time. For that reason, I would avoid such a wet solution.
I believe I would prefer a solution with a beam structure filled in between, for example, starting with a vapor barrier at the bottom, then laying about 2-4cm (1-1.5 inches) of polystyrene insulation boards evenly across the surface, and then floating the necessary height of beams on top. In between, use an inexpensive infill material, especially for impact sound insulation, and screw OSB boards continuously onto the beams. If the top layer (Fermacell, OSB, or similar) is installed continuously at the same level for the other rooms, there should be no cracks at the edges. I understand that sometimes OSB boards are also laid and screwed twice in alternating directions.
A setup like this appeals to me, but of course, you should gather various information on the matter; at the moment, I cannot see anything that would argue against it.
The tradesperson you consult will usually tell you what they know and what they would do with their typical materials—they rarely need to take costs into account because these are often passed on directly.
Take a look online at different options for dry floor construction; there are countless methods available.
Concrete would be absolutely ruled out for the reasons mentioned above, and at 28cm (11 inches) of height, a considerable amount of material and weight would accumulate.
A friend of mine built a larger platform by laying Ytong blocks flat next to each other on the floor and then tiling on top. There are so many possibilities... 😀 You just need to bridge that height somehow, and there are countless variants—I would choose the simplest for myself. Because of the risks mentioned here (crack formation), I would use OSB, Fermacell, or similar materials for the top layer. I’m not sure whether any mat would prevent that.
I believe I would prefer a solution with a beam structure filled in between, for example, starting with a vapor barrier at the bottom, then laying about 2-4cm (1-1.5 inches) of polystyrene insulation boards evenly across the surface, and then floating the necessary height of beams on top. In between, use an inexpensive infill material, especially for impact sound insulation, and screw OSB boards continuously onto the beams. If the top layer (Fermacell, OSB, or similar) is installed continuously at the same level for the other rooms, there should be no cracks at the edges. I understand that sometimes OSB boards are also laid and screwed twice in alternating directions.
A setup like this appeals to me, but of course, you should gather various information on the matter; at the moment, I cannot see anything that would argue against it.
The tradesperson you consult will usually tell you what they know and what they would do with their typical materials—they rarely need to take costs into account because these are often passed on directly.
Take a look online at different options for dry floor construction; there are countless methods available.
Concrete would be absolutely ruled out for the reasons mentioned above, and at 28cm (11 inches) of height, a considerable amount of material and weight would accumulate.
A friend of mine built a larger platform by laying Ytong blocks flat next to each other on the floor and then tiling on top. There are so many possibilities... 😀 You just need to bridge that height somehow, and there are countless variants—I would choose the simplest for myself. Because of the risks mentioned here (crack formation), I would use OSB, Fermacell, or similar materials for the top layer. I’m not sure whether any mat would prevent that.
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