ᐅ Perimeter insulation beneath the foundation slab and additional XPS insulation under the screed?
Created on: 27 Sep 2016 20:44
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GottesJunky
Hello,
Our house construction is getting closer, but today I noticed something that I don’t quite understand. Maybe someone can clarify it for me.
Under the concrete slab (according to the structural engineer 180mm (7 inches), but probably going to be 220mm (9 inches)) there is supposed to be an 80mm (3 inches) perimeter insulation (125m² (1,345 ft²)) installed. The floor build-up according to the architect looks like this:
...
5mm (0.2 inches) carrier board
120mm (5 inches) wood fiberboard insulation, thermal conductivity class 035
20mm (0.8 inches) wood chipboard insulation, thermal conductivity class 035
10mm (0.4 inches) waterproof membrane
Now my question is:
Isn’t this a bit redundant? Wouldn’t just the 120mm (5 inches) XPS insulation board above the slab be sufficient?
It will be a standard house built according to the 2014 energy saving ordinance.
Best regards,
Rico
Our house construction is getting closer, but today I noticed something that I don’t quite understand. Maybe someone can clarify it for me.
Under the concrete slab (according to the structural engineer 180mm (7 inches), but probably going to be 220mm (9 inches)) there is supposed to be an 80mm (3 inches) perimeter insulation (125m² (1,345 ft²)) installed. The floor build-up according to the architect looks like this:
...
5mm (0.2 inches) carrier board
120mm (5 inches) wood fiberboard insulation, thermal conductivity class 035
20mm (0.8 inches) wood chipboard insulation, thermal conductivity class 035
10mm (0.4 inches) waterproof membrane
Now my question is:
Isn’t this a bit redundant? Wouldn’t just the 120mm (5 inches) XPS insulation board above the slab be sufficient?
It will be a standard house built according to the 2014 energy saving ordinance.
Best regards,
Rico
Good morning,
I’m bringing up this “old” topic again because we are currently facing the same question.
I’m not worried about the total weight on the insulation, as this has been tested many times and proven reliable.
Our construction will start around the end of March. We don’t have to, but we have the option to additionally insulate the concrete slab.
The cost for just over 100 sq.m. (about 1,076 sq.ft.) is approximately €2300.
The energy consultant remains inconclusive about this. In their calculation, they believe we won’t save the additional costs within the next 20 years.
Basically, I’m in favor of measures like this—since you really won’t have the chance to do it later—so it’s now or never.
Is the only benefit the increased efficiency of the underfloor heating?
Is the only drawback the additional cost?
I’d appreciate it if anyone could share their opinion or experiences with us.
I’m bringing up this “old” topic again because we are currently facing the same question.
I’m not worried about the total weight on the insulation, as this has been tested many times and proven reliable.
Our construction will start around the end of March. We don’t have to, but we have the option to additionally insulate the concrete slab.
The cost for just over 100 sq.m. (about 1,076 sq.ft.) is approximately €2300.
The energy consultant remains inconclusive about this. In their calculation, they believe we won’t save the additional costs within the next 20 years.
Basically, I’m in favor of measures like this—since you really won’t have the chance to do it later—so it’s now or never.
Is the only benefit the increased efficiency of the underfloor heating?
Is the only drawback the additional cost?
I’d appreciate it if anyone could share their opinion or experiences with us.
G
GottesJunky17 Jan 2018 08:38Hello,
I have decided against it after all!
However, I do have XPS insulation of, I believe, 18cm (7 inches) beneath the stapler plate of the underfloor heating.
What discouraged me were simply the additional costs and the increased extra work, as well as the fact that you never get that money back.
Best regards
I have decided against it after all!
However, I do have XPS insulation of, I believe, 18cm (7 inches) beneath the stapler plate of the underfloor heating.
What discouraged me were simply the additional costs and the increased extra work, as well as the fact that you never get that money back.
Best regards
To be honest, I can’t exactly say why I tend to lean towards it rather than against it. I don’t want to cut corners in the wrong places.
Are there any other benefits besides a small saving on heating costs?
Maybe someone else has chosen this option and can share their reasons why.
Are there any other benefits besides a small saving on heating costs?
Maybe someone else has chosen this option and can share their reasons why.
G
GottesJunky17 Jan 2018 10:25One downside would be the installation of the grounding beneath the slab. This has to be done differently since the insulation cannot be damaged.
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