Insulating concrete veritcally

[DigitalFusion]

is it better to put the vertical insulation in pre or post pour? If you do it post pour, arent you potentially compromising the slab as some of the compacted material may come out from under the slab on the edges, and leave an air pocket?

 

[Steve in Mi]

'Pre' is the way I would do it for the very reason you say.