ᐅ Wall Construction in Solid Building Methods – Experiences?

Johannes1982 schrieb:

Is it even possible to reach KfW 40 standard with 36.5cm Poroton blocks?

If the other components (windows, front door, etc.) are up to the same standard, then definitely yes. We achieved Passive House standard – even with a basement! Using Poroton T6.5 blocks.

We are building a solid brick wall with 42.5 cm (17 inches) unfilled bricks and will achieve KfW40 standard.

Our builder advised us against using insulated bricks because they are expensive, difficult to work with, and, if moisture does get into the construction, hard to dry out.

Our builder would have also installed an external wall insulation system (24 cm (9.5 inches) bricks plus 18 cm (7 inches) wood fiber insulation), but we decided against it for "emotional reasons." Initially, I thought that using only bricks would result in fewer problems with algae-covered façades, but our painter says this is due to the good insulating properties of the wall, which prevent it from drying completely on the outside, not because of the insulation material itself.

familie_s schrieb:

Our contractor advised us against using filled bricks because they are expensive, difficult to work with, and, if moisture gets in on the construction site, hard to dry out.

We’ve also heard this to some extent.
A filled 36.5cm (14.4 inches) brick is only slightly more expensive than an unfilled 42.5cm (16.7 inches) brick – that’s the first myth.
They are only difficult to work with if your work processes are generally not well managed – that’s the second myth.
What moisture would enter the structure during construction that wouldn’t also be possible after completion? – third myth. At the end of the day, the top row of bricks is covered, and that’s it.

What is true, of course, is that the exterior wall loses 6cm (2.4 inches) of living space all around with the same building footprint. If you factor that in against a filled 36.5cm brick, the additional cost actually balances out.

I am a fan of distributing the functions that the exterior wall performs 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 construction with plaster separates weather protection from the rest, all of which is handled by the masonry. This design is susceptible to thermal bridges, for example, due to improper corner detailing, mortar filling of gaps, or numerous slots for plumbing and electrical installations.

A solid brick wall plus external insulation system (EIS) plus plaster decouples thermal insulation from soundproofing and structural functions, making planning easier and errors easier to detect and fix.
The main disadvantage here is the low heat storage capacity of the EIS, which leads to faster algae growth compared to monolithic structures. Heavy insulation materials, such as wood fiber, can help somewhat when a greater insulation thickness is required. However, sound insulation is usually better, and slots for plumbing and electrical work do not affect thermal insulation.

A cavity wall with core insulation finally separates all functions without the disadvantage of algae formation. However, this results in the thickest wall construction and generally the highest cost.

Timber frame construction with plaster carrier board and plaster has different important aspects. An additional vapor retarder layer is necessary because this is not provided by any masonry element, but it allows for a fast and narrow wall build-up. The algae issue here is similar to that of the EIS.
Timber frame with ventilated facade does not have algae problems, but it is more expensive and thicker.

All these build-ups work—some more easily, some require more attention or tolerate fewer mistakes, and others are thicker or more costly.

Allthewayup schrieb:

We have also heard some of this ourselves.
A filled 36.5cm (14.4 inches) brick is only slightly more expensive than an unfilled 42.5cm (16.7 inches) brick—first myth. Difficult to work with only if you generally don’t have your workflow under control—second myth. What kind of moisture on site wouldn’t also occur after construction?—third myth. At the end of the day, the top row of bricks is covered, done.

- Costs: No idea, we haven’t compared. But everyone who has worked with them so far has complained that they break more easily when cutting, and wastage is apparently very high.
- Handling: Even if the masons handle the bricks very carefully, then the electrician, plumber, or whoever comes along, cuts or drills into the wall and causes the next damage. We have looked at several sites, and it doesn’t look good.
- Moisture: No, unfortunately that’s not the end of it. Every vertical edge must be protected from moisture immediately. Window openings need to be plastered right away, drill holes sealed, edges protected when pouring floor slabs, etc. All doable but prone to problems. If the construction site is nearby and you can visit regularly, it can probably be managed.

Here even the brick manufacturer advised against the “trend” of filled bricks for single-family houses during an information event.

We have just finished building and ended up with a solid, cavity wall construction: 17.5cm (7 inches) Poroton + 20cm (8 inches) core insulation + 11.5cm (4.5 inches) Poroton + exterior plaster. A brick facade was not permitted by the building permit / planning permission.