ᐅ Installation of Additional Insulation for Underfloor Heating – Cables Laid on Structural Floor Slab
Created on: 26 Jan 2020 20:40
T
Tx-25
Hello,
We have reached the stage of insulating the underfloor heating. As far as I understood, we were supposed to install the insulation ourselves. However, the installer now says it was agreed that we would also provide the materials.
My questions are:
What materials do I need, or what do you recommend? Our floor construction thickness is 18 to 19 cm (7 to 7.5 inches) on the ground floor and 12 to 13 cm (5 to 5 inches) on the upper floor.
Does the insulation need to be two layers on the ground floor?
What do you think about Gefitas 300 as a vapor barrier? The problem is that the electrician has already run cables across the floor. How should we proceed? Simply lay the foil over the cables?
We have reached the stage of insulating the underfloor heating. As far as I understood, we were supposed to install the insulation ourselves. However, the installer now says it was agreed that we would also provide the materials.
My questions are:
What materials do I need, or what do you recommend? Our floor construction thickness is 18 to 19 cm (7 to 7.5 inches) on the ground floor and 12 to 13 cm (5 to 5 inches) on the upper floor.
Does the insulation need to be two layers on the ground floor?
What do you think about Gefitas 300 as a vapor barrier? The problem is that the electrician has already run cables across the floor. How should we proceed? Simply lay the foil over the cables?
Usually, there is a bitumen strip installed under the interior walls. The bituminous waterproofing membrane for the living areas is then connected to this strip. If you lay this membrane over the cables, there will be gaps at the transition where the cables run from the floor to the wall, right? I’m not an expert, but I would think it makes more sense or is more logical to place it under the cables. The question is, what do the standards say about this?
Try searching for DIN 18195 Part 4
Try searching for DIN 18195 Part 4
seth0487 schrieb:
If you lay this waterproofing membrane over the cables, won’t there be gaps where the cables transition from the floor to the wall? What do you mean by that? The cables are positioned about 20-30cm (8-12 inches) away from all walls. There is also a bitumen membrane under the walls on the ground floor throughout. The membrane we want to use has the advantage that it doesn’t need to be heat-welded because it’s self-adhesive at the edges. The membrane will be adhered onto the membrane beneath the masonry. Only at the joints it won’t be. If I then have to heat-weld the membrane to the existing bitumen membrane under the masonry at those points, the advantage of the self-adhesive edges is largely lost.
I looked at your photo again. The cables also go into the wall, so properly sealing the vapor barrier at the edges is not possible.
I’ll be frank about what I think. It was a really bad idea to try to install the floor insulation yourself to save around 1000 euros, without the necessary expertise. The contractors notice this and take advantage of you. The electrician sticks his cables directly on the concrete without mentioning that the waterproofing membrane is missing. He doesn’t care—it’s not his house. The bricklayer doesn’t say anything either, no warning like, “Mr. xy, the membrane has to be installed now.” You, unsuspecting...oh no, me? I’m supposed to do that? But the cables... The contractors are probably laughing behind the scenes, thinking the inexperienced homeowner wants to do it himself because we are too expensive... The fact is: the membrane must be laid under the cables.
I’ll be frank about what I think. It was a really bad idea to try to install the floor insulation yourself to save around 1000 euros, without the necessary expertise. The contractors notice this and take advantage of you. The electrician sticks his cables directly on the concrete without mentioning that the waterproofing membrane is missing. He doesn’t care—it’s not his house. The bricklayer doesn’t say anything either, no warning like, “Mr. xy, the membrane has to be installed now.” You, unsuspecting...oh no, me? I’m supposed to do that? But the cables... The contractors are probably laughing behind the scenes, thinking the inexperienced homeowner wants to do it himself because we are too expensive... The fact is: the membrane must be laid under the cables.
So, the "structure" looks exactly like ours.
Is a COMPLETE waterproofing of the slab UNDER the cables absolutely necessary?
The walls are built on waterproofing membranes according to the photo,
just as it was done in our case.
We also do not have complete waterproofing of the slab under the cables and pipes, and no contractor has ever mentioned it.
And we get along very well with them, so if there had been a mistake, someone would have definitely pointed it out to us.
Perhaps this whole issue is also related to the way the slab is constructed?
Is a COMPLETE waterproofing of the slab UNDER the cables absolutely necessary?
The walls are built on waterproofing membranes according to the photo,
just as it was done in our case.
We also do not have complete waterproofing of the slab under the cables and pipes, and no contractor has ever mentioned it.
And we get along very well with them, so if there had been a mistake, someone would have definitely pointed it out to us.
Perhaps this whole issue is also related to the way the slab is constructed?
Golfi90 schrieb:
So, the "construction" looks exactly like ours.
Is a COMPLETE waterproofing of the foundation slab UNDER the cables STRICTLY necessary?
In my opinion, YES...
Either with bitumen membrane or Katja....
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