Allthewayup
2023-02-01 21:13:22
- #1
The costs would not drive us to ruin, but I still wouldn’t want it just for fun. The resale value was basically also the argument of the shell builder; from an energy perspective, he also considers it not so important. I can hardly estimate the hobby room with the underfloor heating. Because you don’t necessarily have to actively heat into the ground ;-)
Do you have an energy consultant who can tell you in numbers how big the difference in energy demand would be in your case? I wouldn’t see it as that drastic; after all, you have a certain floor structure under your screed with insulation towards the base slab—even if not much, usually a few centimeters. Then comes at least a 25 cm thick base slab and behind that the soil. I am not an expert here, but I would estimate that 70% of the heating power (due to lower resistance) escapes into the room, 25% "disappears" in the concrete, and only 5% radiates into the ground. But I could be wrong :)
Regarding the [Weiße Wanne]: Well, of course I have read up on it and know why you need it, how it is done, and so on. But that doesn’t make me a complete expert now. So feel free to enlighten me if you feel like it. I at least believe the shell builders we asked have experience and do not (deliberately) botch things. Most people build with [WW] here, and these are established family businesses; everyone knows each other.
Yes, we also built with such a company, and still many things happened; that does not protect you from planning and execution errors, which of course are not done intentionally. That helps you very little once the damage is done. What usage class will the eventual basement fall under, and what exposure class applies to the soil? You should definitely pay attention to what your shell builder writes in the contract. "[Weiße Wanne]" is not a standardized term and is often already used in everyday language when simply a certain type of concrete with a specific water-cement ratio is used. Moreover, many planning and execution-specific steps must be observed for a "real white tub":
- Concrete with high water penetration resistance (concrete quality)
- Controlling construction joints (crack width limitation; crack through the entire component cross-section -> component dimensioning)
- Connection of construction joints through planning measures and execution for high-quality usage (hence the question about the usage class)
- Stresses in the structure (statements on crack width and avoidance as well as reinforcement guidance must be made with the goal of optimizing the construction and avoiding stresses)
- Joint planning and sealing (selection and arrangement), planning of penetrations
- Construction execution (concreting ability, compaction, and curing)
White tubs fall under monitoring class 2 in connection with the load case "water pressure," which is why supervision by an external expert is provided -> DIN 1045-3.
By the way, there is no separate DIN standard exclusively for the construction of white tubs; only the WU guideline makes more concrete statements regarding planning and execution concerning watertight structures.
Based on my personal experience, I would not rely solely on the shell builder from the neighborhood, but everyone must decide that for themselves :-)