Can I concrete onto Kingspan?

[theterracedhouse]

My kitchen floor had to come up as a friend drilled through the water supply. The pipe has been repaired and I have leveled it with Sand, then visqueen and then a thick layer of Kingspan. I have been told the next step is to get the "Barrow Boys" in to chuck some concrete down, level it and then maybe some Screed on top. I called a chap to get a quote to lay the concrete etc but he said you cannot concrete directly onto Kingspan and I need to lay another layer of visqueen so now I am totally confused! Can anyone help please? The kitchen floor is directly onto the earth so I do need the Visqueen down to protect against damp.

Thanks! x

 

[tony1851]

Kingspan recommend a second layer of polythene on top before concreting, but most folk don't bother.
The reason is not clear, but it maybe to reduce the very gradual rate of gas migration from the cells, which slightly reduces its insulation value.
But personally I've only ever known of one Inspector insisting on it.

 

[theterracedhouse]

Wondering if I should change my approach. Visqueen, then concrete, then kingspan?

 

[ringi]

One issue is that if the concrete gets under the Kingspan, then you will never get the Kingspan back down. A layer of polythene is a cheap insurance policy against having your insulation floating in your concrete.