Insulation ON concrete slab?

[wedge73]

Does any of you have a house/garage/building with a concrete slab with insulation on top, underfloor heating on that, and then finished flooring?

I read somewhere about a prominent researcher who believed that this was by far the best construction in terms of moisture properties and thermal efficiency...

Any thoughts?

 

[Beppo]

My guess is probably that it's the same as adding insulation to a wall on the inside. You probably move the dew point into the concrete or between the concrete and the insulation and the concrete.

The idea is otherwise good.

 

[sandhall]

VillaVarm uses such a construction, if I remember correctly.

 

[wedge73]

Ok.. will check with them...

The question is just how to transfer it to the existing garage that is going to become living space..

 

[anaitis]

Does anyone have a house/garage/building with a concrete slab with insulation on top, underfloor heating on that, and then finished flooring.

I read somewhere once about a prominent researcher who believed that this was by far the best construction in terms of moisture properties and heat efficiency...

Any opinions..

It was a long time ago since any serious researcher might have believed this! For the last 30 years, the exact opposite opinion has been held: This is a high-risk construction of the worst kind!

 

[H_L]

It was a VERY long time ago that any serious researcher could have believed this! For the past 30 years, the exact opposite view has been held: This is a riskkonstruktion of the worst kind!

Exactly! Riskkonstruktion was the word.

 

[Pepparkaka]

VillaVarm uses such a construction, if I remember correctly.

Image of VV's floor:
http://www.villavarm.se/showPage.asp?pageId=9

 

[H_L]

Picture of VV's floor: [link]

They seem to have 20-30 cm insulation under the slab as well. Also Platon and ventilation under the insulation on top of the slab. That makes a big difference in this case.

 

[Koorina]

Tips

http://www.isola.se/products/underlayer_for_floors/platon_koneellisesti_ilmastoitu_lattia

http://www.granab.se/swe/ventileradeundergolv.html

 

[mikaelbe]

We have had issues with this. Plastic film on the concrete floor, insulation on top of the plastic. Lots of moisture between the plastic and concrete and a moldy smell. Same story on the walls. Remove everything and redo without insulation and plastic. However, use Platon mat on the floor.

If you have insulation under the slab, it doesn't cause the same moisture problems since the temperature differences are not as significant.

Then warm, humid air inside can condense on a cold concrete slab, which can also lead to moisture problems.

 

[wedge73]

Well, it wasn't more than 1-2 years ago... But can't find it online
...

I agree that it goes against everything that is currently accepted...

I still have a feeling that he seemed to have a point...