Repairing a cold concrete joint between a slab and a shelf

[REDBANANA]

Good evening,

The problem I have is in a residential house. The people had an addition added to the back of the house and when the crew was excavating for the new slab they found the existing houses foundation. The crew finished the excavation and then started to form the new slab. When the slab was finished they formed a shelf, for lack of a better term, to encase the old existing foundation, the houses current foundation is about 20"+/-4" above the new slab. Since the slab and the shelf were poured at different times there is a cold joint between the two. The residents say that when it rains hard the water comes between the joint in the concrete into the basement. Have tried many methods of waterproofing to stops the water with little or no positve results. Wondering if there were any other ideas out there.

 

[ACtrafficengr]

Have you considered underdrain around the entire house perimiter?

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[riznjs]

After striping the 26 ft high column, I feel that there is a Cold Joint at about 5 ft from base, The column size is 1000 x 1000 x 8000. We used especial type of concrete, i.e. self setting concrete to avoid the vibrators.
Now to make sure that the joint, I am observing is a cold joint, if yes what should I do to repair this cold joint.
riz