I am putting an egress window in a below-grade basement with an 8" poured foundation. Do I need to cut the foundation to the top and add a lintel, or will a 10" deep section of the foundation concrete be sufficient as the support above the window? It is a load-bearing wall, and I expect there is re-bar, but I don't know.

This is a project that requires the review by a Professional Engineering who is licensed to practice in your locality. You will most likely need to get this type of project approved by the local agency as part of the building permit process.

Niel Leon
Engineering.com