Do not pressurize underfloor heating before screed - risk?

We want to install underfloor heating in our old building. Since a wet screed is out of the question (weight, wooden walls), it should be a dry system. Unfortunately, even after a long search, we have not found a company that would take on the job, because they always require minimum areas (usually 100 sqm). That is not possible for us, as the old building is inhabited and cannot be cleared of furniture over 100 sqm at the same time. It can only be done room by room. So now we have to do it ourselves. The problem is that we can't find a professional to pressure test it and we've also been told that pressure testing with water may only be done if commissioning follows shortly thereafter. That wouldn't be possible for us, because we first have to lay the floor in each room individually, which will probably take forever, but certainly at least half a year to a year. Leaving the underfloor heating pipes exposed for that long is also not possible, because we can only clear the next room once the previous one has a proper floor again. Accordingly, we want to lay the underfloor heating, then the dry screed on top, and then the next room... but that means the screed would already be on before the final pressure test is done, when everything is truly finished. The manufacturer of the underfloor heating says that if we use aluminum composite pipes (the most expensive), that would not be a problem; the pipes themselves are apparently always (?) tight, the weak points would be the connections at the manifold, but those could still be accessed afterwards. Within the heating circuits there are no interruptions in the pipe, meaning the approach we plan is okay and the risk is low that a brand new aluminum composite pipe would have a hole somewhere in between. Before I proceed this way, I would prefer to ask if this is true, or if each room must be pressure tested individually before the screed goes on (although I don't know how we would do that, since we already have trouble finding anyone who will pressure test a DIY-installed underfloor heating system at all—let alone room by room...). So, what do you say, can this be done relatively safely or is the risk too high?

.....Because a wet screed is out of the question (weight, wooden walls) it should be a dry system....

Whether one should insist on implementing a drywall system is up to each individual to decide. They are less energy-efficient and more expensive when calculated per m². Especially in old buildings, where the room heating loads are often significantly higher than in new buildings.

.....So, what do you say, can this be done quite safely like that ...

Yes. If you have installed the underfloor heating yourself, although I don’t know if it’s properly dimensioned, you can also do the pressure test yourself.

regards

The alternative to the dry system would be no underfloor heating at all. As mentioned, wet is not an option, and the buildup height is also a problem. It’s an old building with the typical problems you usually have there. Besides, we couldn’t let the screed dry for weeks and all the moisture... there are furniture pieces inside. And last but not least, a wet screed is ruled out because the property is not accessible by vehicle and the screed would have to be pumped 30 meters far and 10 meters high; this did not work with the pellets already, so I assume it would be similar with the screed. We also don’t want radiators; there weren’t any before, so no pipes and niches either, and I think the look is no longer contemporary.

The only option left would be wall heating, since we are going to reboard all the walls anyway. We will have to do this in the bathroom as well, since no additional buildup height is possible. The only thing I’d still be concerned about is that I’d like to have warm feet.

Is a wall heating system, which is also installed as a dry system (in some product images it even looks exactly the same), more efficient than an underfloor heating system?

.....We don't want radiators either, there were none before, so no pipes and niches either, and I no longer find the look contemporary....

Radiator niches are an invention of the past century and are actually no longer used today. Certainly, the radiators have to be connected, which can also be done via the underfloor heating.

....
The only option left would be wall heating, since we are reboarding all walls anyway....[/qoute] Wall heating on interior walls would be an alternative. However, the walls must be able to "radiate freely."
On exterior walls, it looks significantly more problematic, especially with a high U-value of the exterior wall and high flow temperatures. The additional insulation effort increases the costs and reduces the living space.

[QUOTE="Elina, post: 63971, member: 21722"]....Is wall heating, which is also installed in the dry system (even looks exactly the same in some product images), more efficient than underfloor heating?

No. Wet systems are also significantly more efficient here.
Basically, for the sensible design of heating surfaces, one must first know the room heat loads, regardless of whether it is radiators, underfloor heating or wall heating.
The permissible flow temperatures are limited (max. heat flux density in, e.g., the living area).
Just burying a few pipes anywhere at will is likely to cause serious problems"!

best regards.[/QUOTE]