Hello everyone,
We are managing our build with individual contracts and have hired a very reputable local shell construction company for the structural work. We did not commission a soil survey before starting construction because the municipality had already drilled on our plot and found that the ground consists of clay and silt.
We are building a KFW 55 house with a basement. Two of the basement rooms have daylight due to a slight slope and are intended to be living spaces with underfloor heating, etc.
For insulating the concrete basement, XPS boards from the company Austrotherm were used. The whole process was supervised by a construction manager.
Now, in our region (in other development areas), more and more people are building, and we noticed that, in most houses, a black coating is applied before the insulation boards are installed, and only then are the boards attached. This was not done in our case; the boards were fixed with mechanical fasteners without this layer.
Both the construction manager and the shell contractor independently say that since we do not have any groundwater pressure, this coating is not necessary.
Am I worrying for nothing, or should I have all the boards removed (would they be reusable or would I have to use new ones?) at my own expense and apply the coating afterward?
The basement has not been backfilled yet.
The contract specifies point fastening, but it does not clearly state whether a bitumen layer or something similar should be applied in between. However, the manufacturer of the boards specifies the coating on their website.
How was this handled in your projects?
We are managing our build with individual contracts and have hired a very reputable local shell construction company for the structural work. We did not commission a soil survey before starting construction because the municipality had already drilled on our plot and found that the ground consists of clay and silt.
We are building a KFW 55 house with a basement. Two of the basement rooms have daylight due to a slight slope and are intended to be living spaces with underfloor heating, etc.
For insulating the concrete basement, XPS boards from the company Austrotherm were used. The whole process was supervised by a construction manager.
Now, in our region (in other development areas), more and more people are building, and we noticed that, in most houses, a black coating is applied before the insulation boards are installed, and only then are the boards attached. This was not done in our case; the boards were fixed with mechanical fasteners without this layer.
Both the construction manager and the shell contractor independently say that since we do not have any groundwater pressure, this coating is not necessary.
Am I worrying for nothing, or should I have all the boards removed (would they be reusable or would I have to use new ones?) at my own expense and apply the coating afterward?
The basement has not been backfilled yet.
The contract specifies point fastening, but it does not clearly state whether a bitumen layer or something similar should be applied in between. However, the manufacturer of the boards specifies the coating on their website.
How was this handled in your projects?
Zaba12 schrieb:
The soil report has arrived, so I can review the matter again with the structural builder and architect.So, what were the results in your case?
Alex85 schrieb:
I find it quite strange that XPS is fastened with dowels in the perimeter area. Especially since the waterproofing of a water-resistant concrete basement depends on the material thickness, which is weakened at the drilling points.
But if even the expert is against breathable walls in contact with soil, things will probably get quite complicated.I don't think it's the most elegant solution... if I had been asked beforehand whether I wanted it that way, I would have said no.
But now it's done, and tearing everything out would probably be disproportionate.
In the meantime, I have much worse problems... see my other thread...
Snowy36 schrieb:
In the meantime, I have much worse problems....see my other thread....That doesn’t sound good.
Where is the other thread, or are you still writing it? 🙂
Alex85 schrieb:
That doesn’t sound good. Where is the other thread, or are you still writing it? 🙂 Well thought, here it is:Exposed roof truss – where is the vapor retarder?
Alex85 schrieb:
I find it quite strange that XPS insulation is fixed with anchors in the perimeter area. Especially since the waterproofing of a waterproof concrete basement depends on the material thickness, which is weakened at the drilling points.
But if even the expert argues against breathable walls in contact with soil, things are probably going to get quite complicated. In our entire development area, regardless of the construction company, this method was used, even for basements designed as a "white tank." All basement insulation boards were anchored. Therefore, I can’t imagine this method contradicting any standards.
bernie schrieb:
This was done throughout our entire development area regardless of the shell construction company, including the basements as watertight concrete structures (white tanks). All basement insulation panels were fixed with anchors. Therefore, I cannot imagine that this method contradicts any standard.Hm. Then that must be the case. Maybe the anchors don’t penetrate deeply enough to reduce the minimum wall thickness.