Geotextile under slab?

[maverick302]

Is there a benefit to using geotextile beneath where the slab goes? It would be placed beneath the stone like so:

Slab
————————
2A modified stone, 6-10”
————————
Geotextile fabric
————————
Prepped dirt pad


Seems there are some conflicting opinions on this. I believe the purpose is so the dirt doesn’t migrate up and mix with the stone, essentially sinking the stone and losing your compacted base. I’ve read some people disagree that this mechanism is a valid concern and there’s a reason it isn’t common.

 

[matt_i]

Can't believe it would ever hurt you. Over a long time the soil fines could start to migrate. Also the criticality of maintaining your slab height is important.

Some of it depends on what kind of point loads you are putting on it.

Thick concrete acts like a washer distributing the load over a larger area thus lessening the propensity to smash little rocks into the subgrade.

 

[Superbowl]

Nobody does that so it can't be necessary.