ᐅ Hollow bricks and mineral insulation—are they a poor combination?

Hello everyone!

Today we had a construction consultation with a friendly small company from the surrounding area that works exclusively with monolithic wall construction. From my point of view, this is commendable, but unfortunately, their services are not affordable for us.

We would have preferred at least a mineral-based external insulation and *no* ETICS (external thermal insulation composite system). During the discussion, it was mentioned that mineral-based external insulation tends to clump, lose its insulating properties, and potentially become damp—and therefore completely unusable—especially when combined with a brick facade, which is already rather expensive for us.

However, I have noticed quite frequently in the neighborhood on renovations and new constructions that mineral insulation blocks are used on the exterior. These buildings, which have sometimes been under construction for a longer period (I have passed by often), have repeatedly been completely soaked by rain during that time. But shortly after the rain, the insulation neither appeared clumped nor otherwise damaged.

What do you think about mineral-based external insulation as a cost-effective compromise between monolithic construction and ETICS? Which materials or possibly specific products are recommended based on experience, particularly for being robust and durable?

Everything is with perforated bricks…

Thanks in advance!

Best regards,
Christian

crion schrieb:
In the discussion, it was said that the mineral external insulation would clump together, lose its insulation value, and possibly (especially in combination with a brick facade, which is rather expensive for us) become damp and therefore completely unusable.

I hope that and the

crion schrieb:
construction consultation with a friendly small company from the surrounding area, which only works with monolithic wall construction

were two different conversations – so with different interlocutors (?)

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crion schrieb:
What do you think about mineral external insulation as a cost-effective compromise between monolithic construction and ETICS?

First of all, mineral insulation on a wall is also an ETICS.

And I have to burst your bubble that this is a cheaper alternative. The additional cost is about €35 per sqm (square meter) compared to ETICS with EPS. Besides the higher material cost, the installation effort is greater because EPS is simply glued onto a smooth surface (which should be the case with new builds), whereas mineral wool is fixed with dowels. The dowels cost money and, above all, time to install. Depending on the house, this can add up to an extra €10,000. It’s not insignificant.

Besides mineral wool, which does not like to be exposed to water (you need to install it quickly and cover it with external render to avoid loss of insulation performance), “mineral insulation” does not necessarily mean mineralwool. There are also mineral insulation boards, for example Ytong multipor or W. Therm MD. However, these are not cheap either, and their disadvantage is a lower thermal conductivity class of 045 (mineral wool and EPS are 035, Neopor is 032), meaning the boards need to be a bit thicker to achieve the same insulation.

Please don’t take horror stories about any wall construction too seriously. All building materials have their pros and cons, and no one installs complete failures on purpose. Construction companies always promote as “top quality” whatever they prefer to use themselves.

Alex85 schrieb:
Please don’t take horror stories about any wall construction too seriously. Every building material has its pros and cons, and no one deliberately installs complete failures. Construction companies always praise as top quality whatever they prefer to use themselves.

And remember my mantra (fully explained in several threads about exterior wall debates – see search function): it’s unwise to try to "retrain" a contractor. If they are very experienced with wall assembly X, you shouldn’t volunteer as a test case for them to learn wall assembly Y.

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crion schrieb:
In the conversation, it was mentioned that mineral external insulation would clump together, lose its insulating value, and possibly (especially with a brick veneer, which is rather expensive for us) become damp and therefore completely unusable.

Why would the insulation behind a brick veneer become wet? That is certainly not correct.

These types of damage do exist. Just like green external thermal insulation composite systems (ETICS) or aerated concrete saturated with water.