I usually stick them down with ardex x7r or mapei keraquick lay the ufh slc with arditex na or mapei fibreplan then tile with x7r or keraquick subject to the type of tiles being fixed.
Tile over foam insulation.
There are several ways to install subflooring above the rigid foam.
12 pk blue charcoal acoustic foam tiles soundproofing foam panels sound insulation soundproof foam padding sound dampening studio sound proof padding 1 x 12 x 12 4 2 out of 5 stars 501 19 99 19.
It s important that there is no movement under the tile.
Some types of thicker foam board insulation are available but they may need to be special ordered.
You can use either one or two layers of plywood or osb and the subflooring can either be fastened to the concrete with long tapcon screws or it can simply float above the foam.
If anything i would use 3 4 exterior plywood over the styrofoam and then an isolation membrane and tile over that.
Foam board insulation is easy to use and is a great diy way to add some insulation.
2x2 foot foam tiles are easy to install over concrete tile or any hard flat surface for basement floors kids room and home exercise areas.
The other way you could approach it is by using a heating pad over the concrete floor with tile i d also use a isolation membrane here over it.
Both require an isolation board or slip sheet.
For tile i d contact the tile council of america or now it s called tile council of north america.