ᐅ Facade insulation with mineral foam boards?

Hello everyone,
We have just become the new owners of a single-family house built in 1954 with zero insulation.
After discussing with an energy consultant, we were advised to install external wall insulation using 16cm (6 inches) mineral foam boards.

Does anyone have experience with this type of insulation? Costs? Necessity?
Or, more generally, does anyone have long-term experience insulating an older building made of 30cm (12 inches) lightweight expanded clay aggregate blocks? Or would it be better to avoid external wall insulation altogether?

Thanks in advance
Best regards, Manuel

Manuel B. schrieb:

Does anyone have experience with this type of insulation? Costs? Necessity?

I believe it’s the cheapest option but with the worst insulation values. An energy consultant can probably give you the exact costs.
Is external wall insulation necessary? I would always recommend it during a major renovation if you also want to upgrade the façade. But initially, focus on insulating the floor ceilings and upgrading the windows.

Manuel B. schrieb:

Or does anyone have longer-term experience insulating an older building with (30cm (12 inches) expanded clay blocks)?

This is done daily—and has been for many years. Both for older buildings and new constructions; there are no fundamental differences.

My question would be why the energy consultant suggests this insulation method. I’m renovating my older building in the coming months as well, but I’m using a different material with significantly better insulation values. Only 12cm (5 inches) of it is enough to easily reach KFW 55 standards for the walls. It does cost a bit more, but for example, the roof overhang does not need to be enlarged.

nordanney schrieb:

My question would be why the energy consultant recommends this insulation option

He said it is a bit more expensive but later does not produce hazardous waste.

nordanney schrieb:

I will also insulate my old building in the coming months

Are you installing a (decentralized) ventilation system?

Manuel B. schrieb:

He said it’s a bit more expensive but doesn’t produce hazardous waste later on.

So, expensive, worst insulation properties (thermal conductivity class 42 or 45) – but a clear conscience? How can you even comply with the energy savings regulations using that?

Manuel B. schrieb:

Are you installing a ventilation system (decentralized)?

Yep! In my previous house, I already had a central controlled ventilation system. I never want to be without one again. Now, however, I’m using only a decentralized system. Model RL50RAS from Raumluft Shop.

There is an article from the Fraunhofer Institute stating that modern ETICS (External Thermal Insulation Composite Systems) are recyclable and do not constitute hazardous waste. We recently insulated with EPS (expanded polystyrene, also known as Styrofoam). I believe it is actually more environmentally friendly than mineral wool, even if it might feel otherwise. What shocked me, however, is that small pieces of Styrofoam are now, and likely will always be, scattered throughout the garden.