Lifespan of different types of foam/xps

[Wallawhoa]

I would have placed it on top of the concrete.

I cast two slabs myself this week. Plastic film at 0.2mm is intended to prevent moisture in vapor form from rising. That it also prevents radon (if you haven't laid radon pipe) is a plus. There are already many threads about it, search and you shall find..

Geotextile and macadam are assumed to be laid if you plan to cast a concrete slab, it would be quite silly otherwise.

thanks!

Would it work to lay solid on the concrete even if you have the film between the foam plastic?

I will probably use albabalk, that doesn't change anything I assume?

 

[MrJay]

I have a solid wood floor, age-resistant foil between the first and second layer of foam plastic. There seems to be divided opinions here in the thread regarding plastic foil so I advise you to talk to your KA before blindly following someone's advice.

 

[Wallawhoa]

I have a massive wooden floor, aging-resistant foil between the first and second layer of cell plastic. There seem to be differing opinions here in the thread, so I advise you to talk to your KA.

Thanks!

Some say you shouldn't place a moisture barrier on the cold side, which in theory would mean you don't need a barrier at all? As long as the residence is heated. Or am I thinking wrong?

I will not have underfloor heating in the slab

 

[MrJay]

There are several schools of thought and preferences on how to do it, you can skip it entirely if you want, but if you have radon you should take care of it through radon pipes and pipe seals. As mentioned, talk to your KA - he should know what your ground situation looks like and whether you need to take any specific action or not. Personally, I like to have both belt and suspenders when building, and plastic foil has never hurt.