ᐅ Exterior Wall for KfW 40 (+) Standard: With or Without External Thermal Insulation Composite System (ETICS)?

The developer acts more or less as the construction manager... we are looking for a company here in the city that will do the brickwork for the house...

Ultimately, the house shouldn’t be too noisy and should be well insulated... and of course, it shouldn’t come with a €20,000 (about $22,000) extra cost. I want to make the best choice for the coming years and then leave my daughters a relatively good house 🙂

guckuck2 schrieb:

When the ETICS facade needs replacing in 50 years, you tear it off and replace it with the then current and suitable insulation material.
What do you do in such a case with a solid wall? Add another layer. Good luck living in a castle.

What more can I really improve in a KfW40 house? Just a little more and you reach Passive House standard. After that, very soon comes nearly zero energy demand. You also have to consider where energy standards come from: a solid building from 1970 often consumes around 300 kWh/m² (30,000 kWh/ft²), while a 40 standard house is under 25 kWh/m² (2,300 kWh/ft²). Nothing will be added on top of that in 50 years. That would be insulation madness times ten.
Regarding wall thickness... we have 40 cm (16 inches) bricks plus plaster. A prefabricated house of this type made only of insulation mats between wooden beams and a panel on each side reaches about 40 cm (16 inches) including plaster. The OP’s example with ETICS using 24 + 18 cm (10 + 7 inches) also ends up the same. They’re all quite comparable.

guckuck2 schrieb:

EPS is the insulation material of today and, for the foreseeable future, as well. Anyone interested in statistics can easily look it up.

Styrofoam leads in the statistics and will certainly continue to do so. ETICS is often the only option for renovations, and Styrofoam is always the cheapest. Still, that doesn’t mean it has to be the future.

ypg schrieb:

What’s your problem? I’m giving my opinion. You asked! And I try to avoid plastics as much as possible, yes.
Seven years ago, when I built, I didn’t have much time or patience to inspect every building block of the house closely. I probably would have still built with external thermal insulation composite system (ETICS / EIFS) back then. But I have lived here for seven years now, and in hindsight, I could have afforded to invest more financially in a “better house.” So I say again: not again!

I also think it’s great that you tell me how to mount things on my facade. The items are already hanging.

I find it more likeable... My next house will be monolithic. Then I will have nice thick interior window sills. That’s also a disadvantage of ETICS.

A swap of arguments leads to discussion. That’s what a forum is usually for.
And I’m not telling *you* how to attach things, but everyone. Because “nails don’t hold well in ETICS” is undeniably true, but I want to propose the thesis that nails are always problematic, only tolerable in wood, especially on facades.
By the way, chewing gum doesn’t stick well to glass.

Baranej schrieb:

Sand-lime brick (calcium silicate brick) is definitely the frontrunner, no question. But so far, I don’t think it’s been confirmed whether this option is available from the builder.

You should follow @11ant’s advice – don’t force anyone to use materials they don’t know (well). It only causes trouble.

Franke86 schrieb:

What would you prefer here?

Read the last 10 pages, then you can pick an opinion 😀

Franke86 schrieb:

To upgrade from the standard 14cm (5.5 inches) ETICS to 18cm (7 inches) ETICS, I have to pay 1800.

Without scrutinizing every penny, that seems reasonable. Besides the extra cost for thicker insulation, you need deeper window sills and parapet flashings.

Franke86 schrieb:

It’s a solid flat roof which will also get insulation and then be greened... so I think it should be good for sound insulation.

Very good. Always go for a solid flat roof and definitely not one made of wood!

WilderSueden schrieb:

What else can I really improve on a KfW40 house? A little more and it meets passive house standard. And soon after comes net-zero energy demand. One must also consider where energy standards come from. A solid-built house from 1970 easily uses 300 kWh/m², a 40 standard house is under 25 kWh/m². Nothing will top that in 50 years. That would be insulation madness to the tenth power.
Regarding wall thickness... we use 40cm (16 inches) brick plus plaster. A prefabricated house of this type, with only insulation mats between wooden beams and boards on both sides, also comes to about 40cm including plaster. The OP’s example with ETICS of 24+18=42cm (9.5 + 7 inches) ends up the same. It’s all about the same.

Our predecessors probably thought the same 50 years ago. Energy was cheap.
Who knows what will happen in the next 50 years.
17.5cm (7 inches) sand-lime brick plus 20cm (8 inches) insulation should be a suitable combination for the OP, totaling 37.5cm (14.8 inches) for a KfW 40 envelope.
I criticized the unnecessarily thick perforated brick, sand-lime brick handles that better. But still, the elephant rule above applies.

Franke86 schrieb:

The developer basically acts more or less as the construction manager... a company will be found here in the city to do the brickwork on the house...

Until now, I thought that by "developer" you meant, in the typical layman’s vague use of terms, the general contractor (the builder to whom you want to entrust the full construction execution). Apparently, your terminology is even more confused – so please clarify who exactly you mean in each case. If I understand correctly now, are you referring to a “mailbox” general contractor???

Franke86 schrieb:

and then leave a relatively good house to the daughters

I wouldn’t count on children settling down or partnering later at their parents’ home location when planning a build today.

guckuck2 schrieb:

I criticized the unnecessary thickness of the hollow clay block; calcium silicate masonry can do better.

What exactly can calcium silicate do better: be thicker? On the contrary, or did you mean that calcium silicate can carry loads with thinner walls and therefore leave more total wall thickness available for the exterior insulation and finish system (EIFS)?

guckuck2 schrieb:

But still, the elephant rule above applies.

The 11ant rule (stone mantra) unfortunately does not include a clause for the case* when you hire a “mailbox” general contractor who already takes care of the masonry: the mason then only executes, while the general contractor handles the planning (if you settle for a draughtsman-type house – although I consider that a misinterpretation of “the first house is built for an enemy” *LOL*).

[*] I sincerely thank you for pointing out this little flaw in my mantra :-)

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Exactly, it’s a company that delegates tasks but manages everything, including planning, structural engineering, etc. (just like an architect).

Yes, the thing with the daughters may be true, but they should have the option or inherit a high-quality house that they can then sell easily.

The company has an excellent reputation. I’ve talked to several people and also know some personally 🙂

Franke86 schrieb:

Exactly, so it’s a company that assigns the tasks but takes care of everything, planning, structural engineering, etc. (just like an architect).

So, an architect who prefers to earn money as a shell general contractor?

Franke86 schrieb:

The company has an excellent reputation.

At this point, people from Cologne inevitably bring up the saying about expensive wool fabrics: that’s unthinkable with cashmere. How is that supposed to work if you have different structural builders?

Franke86 schrieb:

Yes, the thing with the daughters may be true, but they should have that option.

What I meant was: inheriting houses is becoming outdated. People who build a house well under the age of sixty will, in most cases, change it “while it’s still in their hands.”

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