Existing CMU Wall - Hollow or Grout Filled

[the Paper Owl]

Good Evening Everyone,
Although my posts are few and far I truly appreciate how much knowledge I receive from this community, so thank you.

I have a residential remodel project that I am in the beginning stages of design for. A deck will be built and attached to an existing concrete masonry foundation wall. The type of wall (grouted or hollow) will eventually be confirmed through the process of select holes being drilled within the wall (where rebar is expected and where rebar is not expected). My question / hunch is that the wall has to be grout filled for the fact that I can visually see bolted connections for a floor system (ledger boards) that were installed during a previous renovation roughly 4 years ago. I do not see any feasible way that a through bolt attached through only one side of a hollow CMU core (which does not seem to have any screen tube / epoxy) could have held up a floor for all of these years.

Again, this will be confirmed, but I am curious about my hunch.

First image is an area with a two bolt pattern (at wall edge), second image is a single bolt (bolts are spaced at 24" OC), third image is the exact location of the second image but on the outside of the house.

Thank you in advance.

 

[KootK]

Where I'm at, I believe that it's common to solid gout all CMU below grade for durability.

I see you're point with the anchors if they are not of the screen tube variety. I suppose the other option is that they lucked out and hit a bond beam.

 

[DTS419]

I never assume anything favorable, especially in residential construction. Lots and lots of dumb stuff out there that was never engineered.

There are umbrella anchors that make it possible to have a bolted connection like a ledger attached to side of hollow CMU.