Wall construction in solid construction method - experiences?

Is it even possible to achieve KfW 40 with Poroton 36.5 cm?

If the other components (windows, front door, etc.) can keep up, then definitely yes. We achieved passive house standard - even with a basement! Poroton T6.5 brick.

We build with solid 42.5 cm bricks unfilled and achieve KfW40.

On the one hand, our builder advised against filled bricks because they are expensive, difficult to work with, and – if moisture does get into the construction site – difficult to dry.

Our builder would also have executed WDVS ([24er Ziegel + 18er Holzfaserdämmung]), but we decided against it for "emotional reasons." At first, I also suspected that pure brick would have fewer problems with algae-covered facades, but our painter says that is only due to the good insulating properties of the wall, which simply no longer dries out completely on the outside, and not because of the insulation material.

On the one hand, our builder advised us against filled bricks because they are expensive, difficult to work with, and - if moisture does enter the construction site - hard to dry.

We have partially heard that as well.
A filled 36.5 brick is only marginally more expensive than an unfilled 42.5 one - first myth. Difficult to work with only if you don't have your work processes under control in general - second myth. What moisture should enter the construction site that wouldn't also occur after construction - third myth. At the end of the day, the top row of bricks is covered, done.

What is of course a fact is that the exterior wall around costs 6 cm of living space with the same footprint. If I compare that to the filled 36.5, the additional cost actually balances out.

I am a fan of distributing the functions provided by the exterior wall across different layers. This promotes durability and makes error analysis and correction easier:
Wind and weather protection
Thermal insulation
Sound insulation
Structural function

A monolithic structure + plaster leads to a separation of weather protection and the rest, all of which are carried out by the masonry. This results in susceptibility to thermal bridges, for example due to improper corner design or mortar filling of gaps, or many slots for plumbing and electrical installations.

A solid brick + ETICS + plaster decouples thermal insulation from sound and structural functions, making planning easier and allowing errors to be detected and corrected.
The main disadvantage here is the low heat storage capacity of the ETICS, which leads to faster algae growth compared to monolithic structures. Heavy insulation materials, such as wood fiber, can provide some relief here in cases of greater required insulation thickness. However, sound insulation is usually better, and slots for plumbing and electrical installations do not affect thermal insulation.

A two-shell structure with core insulation ultimately decouples all functions without the disadvantage of algae growth. However, it has the greatest wall thickness and, in general, the highest cost.

A timber frame construction with plaster carrier board and plaster has other aspects that might be important. An additional vapor-retarding layer is necessary because this is not provided by any masonry; in return, the wall structure is fast and slim. The same applies to algae growth as with ETICS.
A timber frame construction with ventilated facade has no problems with algae growth but is more expensive and thicker.

All structures work, some more easily, some require more attention or tolerate fewer errors, others are thicker or more expensive.

We have partly heard that too A filled 36.5 cm brick is only marginally more expensive than an unfilled 42.5 cm one - first myth. Hard to process only if you generally don’t have your work processes under control - second myth. What moisture should occur on the construction site that can’t also occur after construction - third myth. Towards the end of the working day, the top row of bricks is covered, done.

- Costs: no idea, we haven’t compared. Everyone who has worked with them so far has complained that they simply break faster when cutting, the waste is apparently enormous. - Processing: So even if the bricklayers handle the bricks with kid gloves, then the electrician/plumber/ whoever comes along, cuts/drills into the wall and causes the next damage. We have looked at several construction sites, it looks bad. - Moisture: No, unfortunately it’s not done with that. Every vertical edge must be immediately protected from moisture. Window openings must be plastered up right away, drill holes sealed, when pouring the floor slabs the edges must be protected, etc., all doable, but prone to problems. If the construction site is nearby and you can check regularly, you can probably keep it under control. Even the brick manufacturer advised against the “trend” of filled bricks for single-family houses at an information event.

We have just finished building and ended up with a massive two-shell wall structure: 17.5 cm Poroton + 20 cm core insulation + 11.5 cm Poroton + exterior plaster. Brick facade was not allowed by the development plan.