ᐅ Insulating from the inside: yes or no?

Hello everyone,

We have an old building and are about to have it completely renovated. I am currently in discussions with two site managers. One of them wants to partially insulate from the inside; where ceilings are being constructed, he plans to add additional insulation with mineral wool to generally reduce impact noise, since the upper floor consists of wooden beams, and also to improve energy efficiency. The other site manager would rebuild everything but would not insulate from the inside. He said that insulating from the inside makes no sense and that if insulation is applied, it should only be done from the outside. Otherwise, there is a risk of mold if ceilings or walls are insulated from the inside. I am now confused—who is actually right?

Thanks in advance, Peter

The interior is always tricky. It needs to be well planned and properly executed. Small mistakes can lead to building damage.

Thank you very much for the tip!

In the end, what really matters is creating a continuous thermal envelope when insulating; otherwise, it’s pointless. It always works better to do this from the outside rather than applying insulation in sections from the inside and potentially making connection errors. So, as @Lumpi_LE says: Insulating from the inside is always a bad idea.

Depending on the intended use, impact sound insulation can make sense, especially with a wooden ceiling. But not with wool.