ᐅ Insulating a Concrete Ceiling on the Upper Floor / What to Consider?
Created on: 20 Oct 2020 21:57
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Piotr1981
Hello everyone,
The shell of the house is finished – the windows are still missing but have a delivery time.
In the meantime, I would like to insulate the upper floor ceiling (concrete) and cover it with OSB boards.
Facts:
- 2-story building
- Upper floor ceiling made of concrete – 20 cm (8 inches) thick
- According to the energy saving regulations certificate for KFW 55, the ceiling must be insulated with 18 cm (7 inches) of polystyrene
- The attic will not be used as living space, only for storage
- The purlins rest directly on the concrete ceiling
- The roof will not be insulated, so the floor will be insulated instead.
Questions:
1) What preparatory work do I need to do on the concrete before starting? Deep cleaning? Any ideas?
2) Do I also need to install a vapor barrier foil on the ceiling of the upper floor?
3) I plan to install the XPS panels in two layers of 9 cm (4 inches) each, staggered to ensure closed joints.
4) Then the OSB boards on top (thickness – no idea – any recommendations?)
5) Should I run the necessary electrical cables into the attic first (for lighting, power, and possibly an access point)?
6) Which boards would you recommend? Has anyone had experience with these?
7) Are there any special considerations I might not have thought of yet?
Looking forward to your opinions/ideas/tips and tricks.
Piotr
And one more thing: What exactly are these polystyrene boards? Are there any cheaper alternatives? What is the difference between EPS and XPS?
The shell of the house is finished – the windows are still missing but have a delivery time.
In the meantime, I would like to insulate the upper floor ceiling (concrete) and cover it with OSB boards.
Facts:
- 2-story building
- Upper floor ceiling made of concrete – 20 cm (8 inches) thick
- According to the energy saving regulations certificate for KFW 55, the ceiling must be insulated with 18 cm (7 inches) of polystyrene
- The attic will not be used as living space, only for storage
- The purlins rest directly on the concrete ceiling
- The roof will not be insulated, so the floor will be insulated instead.
Questions:
1) What preparatory work do I need to do on the concrete before starting? Deep cleaning? Any ideas?
2) Do I also need to install a vapor barrier foil on the ceiling of the upper floor?
3) I plan to install the XPS panels in two layers of 9 cm (4 inches) each, staggered to ensure closed joints.
4) Then the OSB boards on top (thickness – no idea – any recommendations?)
5) Should I run the necessary electrical cables into the attic first (for lighting, power, and possibly an access point)?
6) Which boards would you recommend? Has anyone had experience with these?
7) Are there any special considerations I might not have thought of yet?
Looking forward to your opinions/ideas/tips and tricks.
Piotr
And one more thing: What exactly are these polystyrene boards? Are there any cheaper alternatives? What is the difference between EPS and XPS?
Piotr1981 schrieb:
Not if it is a KfW55 house.
That is specified by the energy saving ordinance. I didn’t mean that you shouldn’t insulate at all.
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benediktr25 Oct 2020 18:33Yesterday we insulated 115 sqm (1,236 sq ft) of the top floor ceiling with 160 mm (6.3 inches) of Puren WLG022. Thanks to the tongue-and-groove edges, it was quite easy to install. From the start, I was determined to build a ventilated cold roof. If you insulate the rafters at an upper floor ceiling and don’t plan to convert the attic into living space at some point (which is not possible for us anyway), you are unnecessarily wasting energy by heating the unused attic space. It’s enough for storing Christmas ornaments or similar items.
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Piotr198125 Oct 2020 20:22benediktr schrieb:
Yesterday, we insulated 115 sqm (1236 sq ft) of the top floor ceiling with 160 mm (6.3 inches) Puren insulation with a thermal conductivity of WLG022. Thanks to the tongue and groove joint, it was quite easy to install. For me, it was clear from the start that I wanted to build a ventilated cold roof. If you insulate the rafters at the top floor ceiling and don’t plan to convert the attic into living space later on (which is not possible for us anyway), you are wasting energy by heating the unused attic. It’s only suitable for storing Christmas ornaments or similar items.
[ATTACH alt="0507671a-dbbc-471e-9a24-caad809e70e1.JPG"]52823[/ATTACH] May I ask how long it took you?
Where did you start, and how do you handle the attic access hatch? Do you install a vapor barrier foil underneath?
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benediktr25 Oct 2020 20:59Piotr1981 schrieb:
May I ask how long it took you?
Where did you start, and how do you handle the access hatch? With a vapor retarder underneath? Of course, you may ask. We started at the eaves since we have a very shallow shed roof. The roof was constructed simultaneously, and the insulation was installed when only the rafters were in place. There were three of us (one cutting, one laying insulation, and one cleaning up), and it took us 12 hours. Underneath is a vapor barrier with an sd-value of 100 to protect the insulation from residual moisture. Generally, as far as I know, no vapor retarder or barrier is necessary for concrete ceilings. We initially cut the membrane around the hatch area with sufficient overlap.
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nordanney25 Oct 2020 22:04benediktr schrieb:
As far as I know, vapor barriers or retarders are generally not required for concrete ceilings.Yep!benediktr schrieb:
As far as I know, a vapor barrier or vapor retarder is generally not required for concrete ceilings.However, if you want to cover the insulation over a large area with OSB panels, then, to my knowledge, it is necessary.Similar topics