ᐅ Aerated Concrete / Brick / Monolithic Construction – Who Has Experience?

Hello everyone,

We have a very nice plot of land in mind. It is tied to a specific developer. The house is planned to be built using solid construction (monolithic method).
We are not construction experts, and none of us have any professional or personal experience with building. Over the past while, we have tried to gather as much information as possible, compared developers (both prefabricated and solid construction), studied and compared technical specifications, and so on... so far, no provider offered solid construction as an option, so this is our first time dealing with it. According to Google, it largely depends on the bricks and the wall thickness. From the project manager, we only know so far that the thickness should be 36.6 cm (14.4 inches), but we do not yet know which type of bricks they are using (we will ask).

What is your general opinion on solid construction? There is so much discussion about insulation that the idea initially felt a bit strange... It is said that no ventilation system would be needed because of this... The house is supposed to meet KFW 55 standards.
By the way, the plot is located near a forest, in case that matters.
What should we pay attention to?

Thank you!

Monolithic means that the wall between the interior and exterior plaster is made entirely of the same material, in this case a brick. A 36.5 cm (14.4 inch) brick will be a porous brick, and the manufacturer does not matter in this context.

KFW55 means for you that the current thermal insulation standard under the 2016 Energy Saving Ordinance is exceeded. The wall structure is therefore technically up-to-date and secure, even without an added insulation layer.

Häuslebauer24 schrieb:
By the way, the plot is located close to the forest, in case that matters.

If you mean the often-mentioned woodpecker effect on facades, that was not the building contractor’s reason for choosing this wall material. Brick is simply one of many building materials used for constructing technically modern houses, and every contractor has their preference. Some use brick, others aerated concrete, and a third one calcium silicate blocks. There are many more options, but these three are the most common. They have differences, but all are suitable.

Häuslebauer24 schrieb:
What should one pay attention to?

As a homeowner, there are so many things to consider that you can already be glad to have the choice of wall material off your list. How exactly did you mean this question?

---

https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

Our house, which we actually moved into today—photos will follow once I’ve tidied up a bit—is built monolithically using 30cm (12 inches) Ytong blocks. On top of that is a lightweight plaster containing expanded polystyrene beads, followed by a colored roughcast plaster that is painted with silicone resin paint. I consider this construction method to be the second best. The best option would be a two-layer ventilated brick facade, the third best a thermal insulation composite system (ETICS) with expanded polystyrene on the wall. Covering polystyrene insulation directly with plaster does not seem a reasonable approach to me. Karsten

With KfW 55 standards, a ventilation system is usually unavoidable. Often, the energy savings from heat recovery are needed to meet the KfW 55 requirements. This means you can expect roughly 14,000 (or 14k) in additional costs for a central ventilation system, unless it is included in the offer.

Regardless, I would not recommend skipping the ventilation system when aiming for KfW 55 or better—unless you really have the time to ventilate regularly yourself.

Nordlys schrieb:
It can’t be reasonable to cover Styrofoam with plaster. Karsten

Why?

To the original poster: In my experience, there are also regional preferences. In Bavaria, a lot of brick construction is common, while in the north, double-wall systems (with brick facing) using sand-lime brick or aerated concrete are often used.

What I would avoid is a “radish” masonry: red on the outside and white on the inside, meaning brick on the outside and sand-lime brick/aerated concrete inside. This is done sometimes, but some builders advised against it because stress cracks can occur more frequently due to the different thermal expansions of the two materials.

Otherwise, advantages of sand-lime brick: high strength and excellent sound insulation, so you can build noticeably thinner walls. However, it has poor thermal insulation, which means you need an external thermal insulation composite system (ETICS / external wall insulation), which does not necessarily have to be Styrofoam—natural materials like mineral wool or stone wool are also possible.

Advantages of aerated concrete: good thermal insulation but lower strength and poor sound insulation compared to sand-lime brick at the same wall thickness. This means you need fairly thick walls—around 36cm to 45cm (14 to 18 inches). To my recollection, 45cm (18 inches) is recommended for KFW55 standard; I’m skeptical whether 36cm (14 inches) is enough. Sometimes ETICS is applied on aerated concrete as well, but personally, I would avoid that if you want to use this material; better to build monolithically. Personally, I don’t like this crumbly material. An outer wall in which you can push in screws or nails by hand?! That’s not my idea of “solid.” [emoji6]

The middle ground, purely objectively speaking, is brick. With or without additional thermal insulation infill (mineral wool or perlite). Made of fired clay with usually many air chambers, it is intermediate in terms of sound insulation and thermal performance: better sound insulation than aerated concrete but worse than sand-lime brick; better thermal insulation than sand-lime brick but worse than aerated concrete. You also need thicker walls compared to sand-lime brick to achieve the same load-bearing capacity. This should be considered especially in buildings with many setbacks and projections. Also, for lintels, builders often recommend using “matching” brick lintels (they should), to keep the same material and avoid cracking issues. It’s not rocket science—it works and is probably not worse, just potentially a bit more expensive than concrete lintels.

Regarding the insulation infills, some believe it’s nonsense: perlite may crumble out when cutting or drilling, and mineral wool infill is suspected to settle over the years. Whether this is true? No idea...

For structural reasons (many large window areas and projections), we chose sand-lime brick with mineral wool ETICS. We originally leaned toward brick. Aerated concrete was and still is not an option for us.

It is important that your builder is familiar with the material and works with it frequently—perhaps even more important than the choice of building material itself. You can build modern houses with any of them.

One more thought regarding KFW55: calculate how much additional effort (financially) achieving KFW55 requires compared to the 2016 Energy Saving Ordinance (EnEV) and see if it makes sense for you.

For me, the numbers didn’t add up, so I consciously decided against it—the 2016 Energy Saving Ordinance is sufficient (for me). My feeling about the whole insulation frenzy: good lobbying, well controlled by politics. [emoji6]

The differences, pros, and cons of various building materials—whether with milk and sugar or black—have already been extensively discussed and debated elsewhere in this forum (and this year, so fresh enough not to have to repeat).

Specifically, this thread is not about the fundamental debate across the entire spectrum—otherwise, as someone native to a pumice mining region, I would have to add another verse about gray stones to the songs about red and white stones—but the original poster basically wants to know

a) what monolithic means and whether it is generally suitable:
this basically means solid, continuous, and homogeneous; and it is still technically relevant today;

b) whether it is safe to trust the builder’s choice of bricks:
yes, that can be done without any concerns.

There is no "right" building material in the sense of “no one opposes it,” but there is a wide range of stones from which flawless walls can be built. Bricks are generally part of this, and especially as aerated clay bricks (filled or unfilled—solid bricks are no longer used as wall building material today, only as facing bricks for cladding), they still meet the current energy-saving regulations. For KfW55 standards, additional measures are required, but these do not necessarily have to take the form of an insulation shell.

Conclusion: from the wall material perspective, the options on offer are perfectly acceptable. So take a deep breath and then read the next paragraph of the project specifications.

ruppsn schrieb:
My feeling about the whole insulation craze: good lobbying that politics has well under control.

Exactly my opinion, but I have said that several times already.

---

https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/