Backfill under decking

[6XSBChamps]

I lose sleep over how much backfill was used for my decking. No issues after a year but I worry about years down the road. In hindsight I wish I had a third party come in during construction and add structural support. I’m wondering if it’s still possible to have a structural engineer take a look and get something in there?

 

[AQUA~HOLICS]

Was the back fill tamped in layers and watered during its placement? You can have an engineer survey the work, my opinion is a secondary retaining wall would be suggested. You must keep support under the flat work or it will crack and possibly move (see picture).

 

[Toxophilite]

If it was flatwork slab, there are no beams to structurally support. As stated above, any preventative measures should be at preserving the integrity of soil foundation.

Ideally, they would have layer-packed stabilized soil/sand and monitored moisture, but that is never done but for house slab pads.

 

[6XSBChamps]

Was the back fill tamped in layers and watered during its placement? You can have an engineer survey the work, my opinion is a secondary retaining wall would be suggested. You must keep support under the flat work or it will crack and possibly move (see picture).

I wasn't there the day they did the backfill. I do know it was very solid after it was done. We had a ton of rain between the time the dirt was dropped and the decking was done. And thats what scares me. I'm not sure if the rain would have actually been a good thing, packing it down or not.

 

[6XSBChamps]

a few more pics before and after. The spot I circled has already been addressed and built up. my biggest worry is the underneath areas that I couldn't see. The decking area was a very big space. I know I should have (and probably will this summer) added more fill off to the sides and not have it slope down right off the deck. I was in a time crunch and wanted to get sod put down to solidify it as much as I could as soon as I could.
I do think a small retaining wall halfway down the slope would help