Water stain on the wall. Suspected thermal bridge. How to proceed?

Good day. During the viewing (in spring, when it was very cold outside and heated inside) of my new condominium, I noticed that there was a kind of water stain on the wall of the balcony door. Above it is a roof terrace. Now I suspect (not only I) that there is a thermal bridge here. Of course, I reported this to the builder. He only said orally, "there is nothing." Now that it is warm, the stain is of course gone. I expect that it will probably reappear next winter. I would like to note this reservation in the handover protocol. What is your opinion on this? An expert can only be on site at the handover. But he will see nothing anymore, as everything is built over. It can only be measured when it is cold outside and well heated inside. So only in winter. Thank you very much for your help. erika

It is more likely to be a leak in the roof terrace. In the case of a thermal bridge, condensation would only form when occupied and/or at high humidity. This would be likely, for example, if screed or plaster had been installed before the stains appeared. A thermal bridge can be identified based on the structural component construction. The BT would then have to present this in detail.

It is more likely to be a leak in the roof terrace. With a thermal bridge, condensation would only form when the space is occupied and/or when the humidity is high. This would, for example, be likely if screed or plaster had been installed before the stains appeared. A thermal bridge can be identified based on the constructive component structure. The BT would then have to present this in detail.

Hello. At that time (spring), there was high humidity in the apartment. Heating had already been turned on. And the plaster had not been applied for long yet. Therefore, it was warm and humid inside and cold outside. The roof terrace had already been completed at that time. Hence the suspicion that it is a thermal bridge. And that is why I want to have this recorded in the acceptance report. But I fear that the BT will put a stumbling block in my way here.

expert report............

It is more likely to be a leak in the roof terrace. In the case of a thermal bridge, condensation would only form in the occupied state and/or with high humidity. This would be, for example, probable if screed or plaster had been installed before the stains appeared. A thermal bridge can be identified based on the structural component design. The BT would then have to present this in detail.

That is not entirely correct. Based on the structural component design, only what was planned can be shown. What was actually executed is a completely different matter. If everything that was planned were actually carried out, fewer experts would be needed.

Thermal bridges would indeed only be meaningfully detectable again in the cold season. Then, as an expert, one can also determine from the surface temperatures whether a defect exists.

Hello Erika,

I will delete a thread from you - please tell me which one, otherwise I will decide. "A lot" doesn't really mean much!

Rhenish greetings