I’d like the bottom of my sonotubes to be well stabilized when backfilling. This clumpy clay like dirt is what I dug up from the bottom of the holes. Do I backfill my tubes with it or can I use just regular soil.

[u/Secure_Choice_100]

Frost line is 48” where my deck is being built

[u/No_Astronomer_2704]

Clay is one of the worst mediums to build on.. Go deeper and remove if able.. Soil is only 1 or 2 levels better and also not recommended.

[u/inigomonto]

If you have some spare rebar, drive three evenly spaced at the inside face of each sonotube until they feel solid before backfilling so they don’t move. After backfilling with either soil you can pull the rebar and repeat. Clay is expansive but as long as the house it is attached to is on the same soil and you manage water properly it will be fine.

[u/Secure_Choice_100 → u/inigomonto]

I happen to have 1/2” x 10’ rebar. I think I’ll do that while backfilling. Deck will be attached and water will be managed.

[u/PurplePickle3]

I just appreciate the the actual data collection