Construction costs are currently skyrocketing

Usually something like that is fixed with "expanding foam" anyway, only nobody sees it afterwards.
Expanding foam is a good insulator

That's true. We once visited a house whose owner was a huge fan of expanding foam. He even foamed the gas-water boiler.

I never said anything about mold, you are just making that up. Stop it.

In practice, it’s all nonsense. But the engineer at the desk, who has to put his signature on it, sees it differently.
You just read that a plumber doesn’t want to place it in the outer wall because of frost risk. That’s what reality looks like.
Next, the structural engineer will scream because someone would hollow out the load-bearing wall …

The rapidly rising prices for energy and building materials are putting the construction industry on alert: In the second quarter alone, prices for residential, office, and commercial buildings increased by between 17.6 and 19.4 percent compared to the previous year, according to data from the Federal Statistical Office. According to a study by the consulting firm PricewaterhouseCoopers (PwC), first reported by the "Handelsblatt," an end to the price increases is not in sight anytime soon. Builders must expect prices to continue rising for at least the next two years. "We expect that construction prices for real estate will increase by more than 20 percent over the next two years," says Harald Heim, partner and real estate specialist at PwC.

And in recent days, several clients (real estate investors/developers/project developers) have told me that the general contractors (GUs) a) are now across the board again offering fixed prices without sliding clauses or daily prices (e.g., for steel) b) prices are now going down again (albeit at a high level) c) are sending some employees to short-time work, as order books were full but many clients have dropped out and orders have been canceled d) are suggesting to my clients to postpone projects to 2023, when more than sufficient capacities will be available again and consequently attractive prices will be offered again (otherwise the GUs are tending toward "sending our staff into short-time work") The GUs and projects concern undertakings starting from around €20 million, partly commercial (logistics, office) and partly developer projects (multi-family residential construction). All signs currently point to a relaxation. However, this does not mean that there will be dumping prices again.

All signs currently point to the property market relaxing. However, this does not mean that there will be dumping prices again.

Yes, because even if energy prices remain critical, in my opinion there is a lot of potential for price reductions due to the clearly and significantly declining demand. The demand-driven increases over the past 5 years have certainly contributed well to the industry's margin; these are the reserves that will be tapped when the market turns. Ultimately, one must adapt, possibly take some losses, and rationalize wisely. Energy-intensive building materials will probably no longer be sourced locally but imported – transport capacity will be available next year.

Yes, because even though energy prices will remain critical, in my opinion there is a lot of potential for price reductions due to the clearly and significantly declining demand. The demand-driven increases of the last 5 years have certainly contributed well to the industry's margin; these are the reserves that will be tapped when the market turns. Ultimately, one has to adapt, possibly make sacrifices & rationalize wisely. Energy-intensive building materials will probably no longer be sourced locally but imported – transport capacity will be available next year.

Basically correct that the margin of the construction industry will decrease. However, I do not see this happening through lower prices for the end consumer, but rather through increased labor and procurement costs. I think something will happen starting in October regarding the wage-price spiral; it will also not be easy for the construction industry to remain inactive, even if they have so far been above the new minimum wage.