Talusen t1_j1kgff2 wrote on December 25, 2022 at 2:15 AM

Do you only care about the moisture barrier?

A lot of suggestions are going to do what you've mentioned, and try to:

Make it structural.

Tie it into the existing foundation.

Prevent water intrusion

(in that order)

Moisture barrier alone? Get a piece of dimpleboard on the opposite side, possibly with some cementboard backing it to give it some strength.

Moisture and vapor? Peel and stick on the cement board, then as above.

Properly fixing it? Check to see if they did something fun with a sill plate and the rubble you're seeing. Clear out the rubble.

Drill into both sides of the gap about 6" and use simpson set-xp to install 4-5 pieces of #4 rod. (fitting the rod in both sides vs wiring 2 pieces that are in one side apiece together in order to develop the connection properly is above my paygrade)

Get plywood on both sides of the gap, and secure it to the foundation. (do more than just this, but I don't know forms well enough to tell you specifics) Put a bonding agent on the existing concrete to prevent a cold joint. Talk to the staffer at ( Whitecap/your concrete supplier ) and fill with the self-consolidating concrete or no-shrink grout they recommend.

Wait a week or so (mist the top daily with cool water) before you pull the forms and see how you did.

Edit: whoever did your foundation should get a good kicking for not doing their job properly, ditto the inspector for the city, and whoever inspected your home at time of purchase.

It LOOKS like they framed around it, so there's a chance this is only a cosmetic problem, but that needs an engineer to say for certain.

HopeOk8502 t1_j1ksghm wrote on December 25, 2022 at 4:14 AM

Thank you! That’s a great response. I’m going to check for a sill and see how stuck those rocks are.. I really like the suggestion of a bonding agent to create a moisture barrier. I’m not super concerned with the structural strength of it (but maybe I should be?).

Talusen t1_j1l1w10 wrote on December 25, 2022 at 5:59 AM

The bonding agent won't do squat as a moisture barrier; it's a form of glue. It's only there to make sure the bond between old concrete and new is sound.

All told, this looks bad but is probably ok.

That said, I am a person on Reddit. If you want sureity, hire a structural engineer who'll come out and let you know what's going on. The few hundred it'll cost will pay for itself if you ever sell the house and the buyers go "what's this?"