I have plans to build a living space in the storage room; it's a slab on grade without insulation. What should be done to make it suitable? Can I, for example, lay a moisture protection mat against the slab/wall and 1-2dm of cell plastic on top of that, or how do you do it?
Maybe floor heating, just plans for now.
Maybe floor heating, just plans for now.
I am considering the same ideas as you. I have a garage/storage space of 35 sqm that I plan to convert into living space. It turns out it would have been much easier if I just had a piece of land instead... The garage I have today was converted into living space in 1973. The construction is an uninsulated concrete slab/age-resistant building plastic/70mm foam/grooved chipboard and then carpeting. Now that I have started tearing it apart, I can see that under the building plastic it is soaking wet, but no moisture has risen and discolored the chipboard. In the walls, the moisture has risen and made the insulation wet at the bottom, the drywall crumbles at the bottom 20cm, and the wood has started to rot. The conclusion is: Dig out about 50cm, lay a capillary-breaking layer in the form of macadam, then 300mm foam S100 and finally a slab with waterborne underfloor heating.
You already have a finished slab...? So it’s not possible to lay macadam and insulation underneath now without redoing everything...
Since you have an uninsulated slab-on-grade, you should expect it to always have 100% relative humidity.
This means that any materials you allow to stay in permanent contact with the slab will absorb moisture until they are saturated at the boundary layer. Any organic materials like wood will therefore mold or even rot.
I imagine if you cover the entire slab with 0.2 mm age-resistant diffusion-tight plastic, make sure to have proper overlap at the seams and possibly glue the film together at the seams with mold-resistant silicone (or maybe acrylic sealant would work?).
Then you lay either rubber sill bands or strips of roofing felt under all joists fastened to the slab; rubber or this kind of roofing felt seals decently around the screws you use to fasten the sill.
Now you should be able to lay foam insulation on this surface with the desired flooring on top of the foam. Possibly with underfloor heating (+ plates) in channeled foam if you wish.
I should also add that I am absolutely not an expert in this, so I think you should try to find someone else who supports that this is a suitable method before you get started, if you decide to go with this method.
Since you have an uninsulated slab-on-grade, you should expect it to always have 100% relative humidity.
This means that any materials you allow to stay in permanent contact with the slab will absorb moisture until they are saturated at the boundary layer. Any organic materials like wood will therefore mold or even rot.
I imagine if you cover the entire slab with 0.2 mm age-resistant diffusion-tight plastic, make sure to have proper overlap at the seams and possibly glue the film together at the seams with mold-resistant silicone (or maybe acrylic sealant would work?).
Then you lay either rubber sill bands or strips of roofing felt under all joists fastened to the slab; rubber or this kind of roofing felt seals decently around the screws you use to fasten the sill.
Now you should be able to lay foam insulation on this surface with the desired flooring on top of the foam. Possibly with underfloor heating (+ plates) in channeled foam if you wish.
I should also add that I am absolutely not an expert in this, so I think you should try to find someone else who supports that this is a suitable method before you get started, if you decide to go with this method.