Hello,
Here is my next question.
The floor structure is as follows:
- No insulation under the slab
- 20 cm (8 inches) concrete
- Torch-on membrane G 200 S4
- 13 cm (5 inches) insulation
- 6.5 cm (2.5 inches) screed
- 1 cm (0.4 inches) floor covering
I have agreed with the plumbing company that we will handle the insulation design for the floor ourselves.
The contractor’s quote included 6 cm (2.4 inches) WLG 035 + 5 cm (2 inches) WLG 035 + 3 cm (1.2 inches) Rolljet 045.
The Rolljet 045 was already supplied by the contractor. I will source the insulation boards myself since it is significantly more cost-effective.
Here are the options I have checked using the U-value calculator (ubakus):
- General purpose EPS insulation board 035 DEO/WAB General purpose insulation board for €1,305.71 including VAT
Calculated U-value 0.265
- Austrotherm insulation board XPS-Top 30 SF WLS 032 for €1,590.78 including VAT
Calculated U-value 0.247 (additional €285.07)
- IKO Aluminum PIR insulation board Enertherm WLS 023 for €2,065.45 including VAT
Calculated U-value 0.19 (additional €474.67 or €759.74)
Is the following calculation for comparing U-values 0.265 versus 0.19 correct?
0.075 W/m²K (difference in U-value) x 84 kKH (annual heating degree hours) x 100 m² = 630 kWh annual savings x €0.065/kWh = €40.95 heating cost savings per year
This would mean the additional cost is amortized after 18.5 years. Less if gas prices rise.
How would you decide? Since we are doing this ourselves, the extra cost would be affordable, but if it is not necessary, naturally we'd spend the money on something more sensible.
PS: My buddy recommends laying a PE foil under the insulation and on top of the torch-on membrane. My plumbing company says this is not necessary. What do you think?
Here is my next question.
The floor structure is as follows:
- No insulation under the slab
- 20 cm (8 inches) concrete
- Torch-on membrane G 200 S4
- 13 cm (5 inches) insulation
- 6.5 cm (2.5 inches) screed
- 1 cm (0.4 inches) floor covering
I have agreed with the plumbing company that we will handle the insulation design for the floor ourselves.
The contractor’s quote included 6 cm (2.4 inches) WLG 035 + 5 cm (2 inches) WLG 035 + 3 cm (1.2 inches) Rolljet 045.
The Rolljet 045 was already supplied by the contractor. I will source the insulation boards myself since it is significantly more cost-effective.
Here are the options I have checked using the U-value calculator (ubakus):
- General purpose EPS insulation board 035 DEO/WAB General purpose insulation board for €1,305.71 including VAT
Calculated U-value 0.265
- Austrotherm insulation board XPS-Top 30 SF WLS 032 for €1,590.78 including VAT
Calculated U-value 0.247 (additional €285.07)
- IKO Aluminum PIR insulation board Enertherm WLS 023 for €2,065.45 including VAT
Calculated U-value 0.19 (additional €474.67 or €759.74)
Is the following calculation for comparing U-values 0.265 versus 0.19 correct?
0.075 W/m²K (difference in U-value) x 84 kKH (annual heating degree hours) x 100 m² = 630 kWh annual savings x €0.065/kWh = €40.95 heating cost savings per year
This would mean the additional cost is amortized after 18.5 years. Less if gas prices rise.
How would you decide? Since we are doing this ourselves, the extra cost would be affordable, but if it is not necessary, naturally we'd spend the money on something more sensible.
PS: My buddy recommends laying a PE foil under the insulation and on top of the torch-on membrane. My plumbing company says this is not necessary. What do you think?
Rolljet is used for impact sound insulation. Please do not omit it under any circumstances. Not a good idea.
Improving the insulation only makes sense, if at all, on the ground floor, obviously. The expensive PUR material is usually only used if there was a miscalculation in height and suddenly there is no room left for regular EPS with a thermal conductivity of 0.035 W/(m·K).
I would definitely not invest more money than necessary.
Improving the insulation only makes sense, if at all, on the ground floor, obviously. The expensive PUR material is usually only used if there was a miscalculation in height and suddenly there is no room left for regular EPS with a thermal conductivity of 0.035 W/(m·K).
I would definitely not invest more money than necessary.
guckuck2 schrieb:
Rolljet is used for impact sound insulation. Please do not skip it under any circumstances. Bad idea.Rolljet is nothing more than EPS with an attached foil printed with a grid.
B
boxandroof12 Apr 2019 16:09guckuck2 schrieb:
I definitely wouldn’t invest more money than necessary. Necessary for what?
The original poster has already calculated from when it becomes cost-effective. And whether it's 10 years more or less, the decision boundary has to be drawn by the original poster themselves.
They can plan the next house sooner, but the current building height seems fixed and not unusual.
Expensive only on the ground floor/against the ground, good point.
P
pffreestyler12 Apr 2019 16:32The plan was made correctly and on time. The door installation ended up being 0.5 cm (0.2 inches) too deep, the screed installer was a bit too cautious, and Rolljet has poorer insulation values—together, this caused the "problem." I have now spent almost 800 € more (still below the planned budget), but I achieved a 0.05 better U-value instead of a 0.05 worse U-value, which puts my mind at ease. By the way, this only applies to the ground floor. The upper floor won't have this.
Was this clever? I don’t know. I’m usually quite frugal, but now I feel good about it. Cost optimizers like Nordlys would probably be horrified.
Was this clever? I don’t know. I’m usually quite frugal, but now I feel good about it. Cost optimizers like Nordlys would probably be horrified.
does02 schrieb:
Rolljet is basically EPS with an attached foil printed with a grid.The standard insulation board under the screed is of type DEO dm (internal insulation for ceiling/floor with medium compressive strength), whereas Rolljet is of type DES sg or sm (internal insulation for ceiling/floor with sound insulation requirements and medium/high compressibility).
The latter typically has a footstep sound insulation rating of 25-30 dB.
They are definitely not the same. Please do not spread such misinformation.
pffreestyler schrieb:
Utility knife for cutting and then piecing it together?You won’t get far using a utility knife on aluminum-coated PUR panels. Get a jigsaw or a small reciprocating saw, preferably cordless.
I also don’t really understand the purpose of the recommended PE foil. However, you can simply tape the joints of the top insulation layer, which will then act as a vapor barrier.
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