How to Handle Moisture in Concrete Floors?

[Daro]

I have an insulated garage where the back has been converted into a hobby room (which is used a few times a month) with its own entrance. The floor is currently just concrete, but I'm considering laying joists, mineral wool, and OSB on top to increase the comfort of the room and also improve the acoustics a bit. However, I'm unsure about how to handle the moisture from the floor/concrete slabs. I've read various solutions and I'm not sure which is correct. My initial thought was to use a durable construction plastic, but I've heard about possibly needing Platon mat and other alternatives. What exactly should I do?

 

[Maalkl]

Is the concrete slab uninsulated?

 

[Daro]

Is the concrete slab non-insulated?

It is insulated. (Has foam plastic underneath) and was built 2 years ago.

 

[Maalkl]

Since you have insulation underneath, you don't need insulation on top. There isn't much moisture coming from below. You have modern construction and can do as is typically done in modern houses. Plastic film under the parquet if that's what you want, for example. There are laminate/vinyl floors with vapor barriers and some built-in soundproofing as well. If you want good acoustics and comfort, install a carpet.

 

[Daro]

Int

Since you have insulation underneath, you don't need insulation on top. There isn't much moisture coming from below. You have a modern construction and can do as is commonly done in modern houses. Plastic foil under the parquet if that's what you want, for example. There are laminate/vinyl floors with a vapor barrier and some built-in step soundproofing as well. If you want good acoustics and comfort, install a carpet.

Thanks for the tips! 😊
I have a thin carpet today and find the floor very cold. That's why I was considering insulation, but it sounds like I've been on the wrong track?

 

[Daro]

According to GPT-5, it should be possible to lay cork underlay and then OSB boards on top of it. Is that correct? Is it really safe concerning moisture?

 

[Jansson69]

No, in Sweden we rarely lay OSB on floors without chipboard or fiberboard, which are laid floating.

 

[Daro]

why is particle board preferable?
And can you lay cork on the concrete and then the particle board on top of that?

 

[Jansson69]

No, just explained what is used, construction plastic XPS insulation and a floating 6mm underlayment..

https://eviabygg.se/sv/products/happy-step-stegdampare-6-mm

Or construction plastic, lumpapp and parquet..

 

[Daro]

No, just explained what is used, construction plastic XPS insulation and a floating 6mm subfloor..

[link]

Or construction plastic, lumpapp, and parquet..

So all would work equally well? 😊
Happy Step, would it be used between construction plastic and chipboard flooring?