Hello everyone,
I want to undertake the insulation of the top floor ceiling myself.
[Facts]:
- Semi-detached house built in 1972, two floors with heated basement rooms
- Upper floor ceiling made of reinforced concrete - B225, thickness according to plan 16cm (6.3 inches)
- Roof pitch is 18 degrees and cannot be converted into living space
- The purlins rest directly on the concrete ceiling
- The roof will not be insulated; instead, the floor will be insulated
- The attic space should be partially usable as storage and walkable
See sketch top view attic 110 sqm (1184 sq ft) area, approx. 40 sqm (430 sq ft) walkable
[Questions]:
1) Preparations:
What preparations do I need to make on the concrete before starting work? Thorough cleaning?
2) Vapor barrier:
Do I also need to install a vapor barrier foil on the reinforced concrete B225 at the upper floor?
3) Insulation material:
I plan to lay EPS 040 WI/DI/DZ 50mm (2 inch) polystyrene boards (width 500mm (20 inches) x length 1000mm (39 inches)) double-layered and staggered (without cross joints) everywhere.
This means about 9-10cm (3.5-4 inches) of insulation thickness. What U-value would I achieve with this?
Material cost comes to around 800 EUR including VAT.
Which affordable insulation boards would you recommend for my project? Has anyone had experience using polystyrene boards?
4) OSB boards (thickness - no idea - any recommendations)?
For the walkable area I would additionally install OSB-3 tongue and groove boards, 12mm (0.5 inch) thick, 205cm (80 inches) x 62.5cm (25 inches).
Material cost is approximately 200 EUR including VAT.
5) How should I deal with cables embedded in the concrete ceiling and around the purlins when insulating?
6) How should/could I insulate the attic stairs?
7) Are there any special considerations I might have overlooked?
Looking forward to your opinions/ideas/tips and tricks,
Chippy
I want to undertake the insulation of the top floor ceiling myself.
[Facts]:
- Semi-detached house built in 1972, two floors with heated basement rooms
- Upper floor ceiling made of reinforced concrete - B225, thickness according to plan 16cm (6.3 inches)
- Roof pitch is 18 degrees and cannot be converted into living space
- The purlins rest directly on the concrete ceiling
- The roof will not be insulated; instead, the floor will be insulated
- The attic space should be partially usable as storage and walkable
See sketch top view attic 110 sqm (1184 sq ft) area, approx. 40 sqm (430 sq ft) walkable
[Questions]:
1) Preparations:
What preparations do I need to make on the concrete before starting work? Thorough cleaning?
2) Vapor barrier:
Do I also need to install a vapor barrier foil on the reinforced concrete B225 at the upper floor?
3) Insulation material:
I plan to lay EPS 040 WI/DI/DZ 50mm (2 inch) polystyrene boards (width 500mm (20 inches) x length 1000mm (39 inches)) double-layered and staggered (without cross joints) everywhere.
This means about 9-10cm (3.5-4 inches) of insulation thickness. What U-value would I achieve with this?
Material cost comes to around 800 EUR including VAT.
Which affordable insulation boards would you recommend for my project? Has anyone had experience using polystyrene boards?
4) OSB boards (thickness - no idea - any recommendations)?
For the walkable area I would additionally install OSB-3 tongue and groove boards, 12mm (0.5 inch) thick, 205cm (80 inches) x 62.5cm (25 inches).
Material cost is approximately 200 EUR including VAT.
5) How should I deal with cables embedded in the concrete ceiling and around the purlins when insulating?
6) How should/could I insulate the attic stairs?
7) Are there any special considerations I might have overlooked?
Looking forward to your opinions/ideas/tips and tricks,
Chippy
chippy79 schrieb:
Quite a situation, isn't it? Pipe insulation from the hardware store?
Not ventilating the insulation means I have to make sure the insulation boards always lie flat against the concrete floor, right? So if there are cables or other empty conduits laid on the floor, do I need to cut a V-groove underneath?
ThanksNo matter what you use, the main thing is that it provides some insulation. Go ahead and use mineral wool. Just put it in, and that’s fine. Yes, exactly, no gaps allowed. If air flows beneath the boards, the insulation is useless. So it’s actually a good idea that you want to lay something on top. But any unevenness is basically the death of rigid insulation.
So, I am still in the process of clearing out and cleaning the attic. Almost done – now I wanted to ask about the procedure for installing the PUR insulation boards. I just realized that beneath the 16cm (6.3 inches) reinforced concrete floor, there is another type of insulation I wasn’t aware of, and on top of that, there is 5cm (2 inches) of screed. Does this change anything regarding the installation?
The insulation boards are 16cm (6.3 inches) thick PUR with aluminum facing and tongue-and-groove edges. I was planning to lay the boards directly on the broom-cleaned attic floor, meaning without a vapor barrier and loose-laid.
In another forum, I read that with PUR boards you need to make sure they don’t have any gaps underneath, because air can circulate and significantly reduce the insulation performance. This can be prevented either by gluing the boards to the floor with a construction adhesive (like a simple tile adhesive) or by laying a thin layer of mineral wool underneath.
What do you think? I would actually like to avoid this extra effort :-( or is it really necessary? If yes, how thick should the mineral wool be, and wouldn’t I then need to install a vapor barrier because of the mineral wool being laid directly on the screed?
On top, I would lay 15mm (0.6 inches) OSB panels in the walking areas.
The insulation boards are 16cm (6.3 inches) thick PUR with aluminum facing and tongue-and-groove edges. I was planning to lay the boards directly on the broom-cleaned attic floor, meaning without a vapor barrier and loose-laid.
In another forum, I read that with PUR boards you need to make sure they don’t have any gaps underneath, because air can circulate and significantly reduce the insulation performance. This can be prevented either by gluing the boards to the floor with a construction adhesive (like a simple tile adhesive) or by laying a thin layer of mineral wool underneath.
What do you think? I would actually like to avoid this extra effort :-( or is it really necessary? If yes, how thick should the mineral wool be, and wouldn’t I then need to install a vapor barrier because of the mineral wool being laid directly on the screed?
On top, I would lay 15mm (0.6 inches) OSB panels in the walking areas.
N
nordanney15 Dec 2020 14:58chippy79 schrieb:
What do you think? I'd actually like to avoid this effort :-/ or is it really recommended?chippy79 schrieb:
No feedback from you? Would be nice.. thanksGladly ;-)If the floor is smooth, I would skip the effort. There will also be some pressure on the insulation from the OSB panels.
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