ᐅ Which type of stone is best for exterior walls?

sirhc schrieb:

I have some general questions regarding wall construction. Should I log off just because I know a structural engineer?

Relax, or to put it plainly: stay calm.

I don’t think you should be surprised by the suggestion to consult your structural engineer. You mention the option of 24 cm (9.5 inches) masonry but don’t explain the reasoning behind it. Later on, you reveal that a railway line runs close to your plot. How often do trains pass by? Once per hour, every 20 minutes, or more frequently? Is it regular passenger service or freight traffic?

sirhc schrieb:

I just assumed/claimed that a “thin” wall that is not made of calcium silicate bricks plus insulation is the cheapest option because according to my understanding, the standard is described in the construction specifications, and you can always pay extra for more.

We are building purely monolithically with 36.5 cm (14 inches) masonry; does that make us an “outlier” because the building specifications you have refer to masonry plus external insulation? By the way, Ytong® PP with a lambda value of 0.07 W/(mK) and a thickness of 36.5 cm (14 inches) offers one of the best insulation values for bricks while maintaining good load-bearing capacity.

Again, there is no “one” masonry type for every construction project. Each plot and the needs or preferences of the future residents require individual consideration. If I were you—and I’m certainly not a fan of brick plus insulation—I would move away from aerated concrete or porous clay blocks and actually opt for calcium silicate bricks. This especially applies if a) the noise level from the railway is fairly high or b) you are very sensitive to noise. However, I would consider a different insulation material instead of the often-praised external thermal insulation composite system (ETICS).

If the noise level is tolerable, you can stick with 17.5 cm (7 inches) hollow brick or aerated concrete plus 16 cm (6 inches) of insulation. What the prefabricated brick might lack is compensated for by the 16 cm (6 inches) of insulation.

Regards, Bauexperte

I’m completely calm.

There are 6 passenger trains per hour running on the railway line, plus an occasional freight train (sometimes at night).

You’re not an exception (I’ve read about this scenario before), but I would guess that 17.5cm (7 inches) masonry with insulation is more cost-effective than 36.5cm (14 inches) masonry. That’s probably why 17.5cm (7 inches) masonry with insulation is specified in the building scope description.

I also know that there’s no perfect material. In general, sound insulation plays a bigger role here than in other places.

The next question regarding your suggestion would be how much worse 17.5cm (7 inches) sand-lime brick plus 16cm (6 inches) insulation insulates compared to 17.5cm (7 inches) aerated concrete plus 16cm (6 inches) insulation, or whether the insulation thickness should be increased beyond the original 16cm (6 inches) if sand-lime brick is used.

Best regards

The insulation boards would be the same in both cases, and since the masonry contributes almost nothing to thermal insulation, the overall values should only differ negligibly.

Regarding costs, it's difficult to give exact figures, as each supplier tends to calculate differently. Basically: what sells well (i.e., is in high demand) costs less. This applies to aerated concrete for some, sand-lime brick for others, and Poroton for yet another. By the way, with monolithic wall construction, you save the second work step, so overall it doesn’t necessarily have to be more expensive. However, there are other aspects to consider in that case...

In summary: get concrete quotes and ask why exactly that is being offered to you. Then you can form your own opinion — or ask again here.

Good luck

K1300S

sirhc schrieb:

I am perfectly calm.

sirhc schrieb:

There are 6 passenger trains per hour on the railway line, plus occasionally a freight train (including at night).

That’s quite a lot; but you can still have a conversation in the garden, right?

sirhc schrieb:

... I would guess that 17.5cm (7 inches) masonry plus insulation is cheaper than 36.5cm (14 inches) masonry? And that’s why 17.5cm (7 inches) masonry plus insulation is specified in the building scope.

Not really. But it depends on the supplier’s purchasing conditions. If they indicate to their supplier—outside of the annual negotiations—a volume of about 30 homes for the coming year, built with aerated concrete, their purchasing terms for calcium silicate bricks will likely be less favorable than if they had agreed on terms for 30 homes per year in general.

sirhc schrieb:

The next question related to your suggestion would be how much worse 17.5cm (7 inches) calcium silicate brick plus 16cm (6 inches) insulation insulates compared to 17.5cm (7 inches) aerated concrete plus 16cm (6 inches) insulation, or whether the insulation should be thicker when using calcium silicate bricks than the original 16cm (6 inches).

This can’t be answered in general because the site-specific data aren’t known.

In your position, I would postpone this decision until after the heat demand calculation. Once you know the energy requirements of your new building, you can “experiment” with different bricks and insulation thicknesses in calculations; even try different thicknesses as long as the building permit/planning permission has not been submitted.

Edit: Of course, only if your supplier can economically source all possible bricks or you are building with an architect.

Regards, Bauexperte

Bauexperte schrieb:

That is quite a lot; but you can still have a conversation in the garden, right?

First of all, thanks to all of you!

The passenger trains are modern regional trains (RB/RE) powered by electricity and they don’t make much noise or noise for long. They travel slowly because the station is very close by. So maybe each train is too loud to talk over for about 5 seconds.

It’s the freight trains that really make loud and longer-lasting noise.