A stud rotted away in my foundation now I'm left with a large hole. Any suggestions on how to patch would be great. A foam spray would be easiest but probably wont hold.
Welcome to the site. I guess you have figured out that there should be no wood in the concrete.
Is it just an unsightly blemesh or a hole that allows critters or water in and was the wood important to the structure. Perhaps post a photo.
What was the stud doing (except rotting)? Did it support something? Does it need replacing?? Once that issue is clear, we can advise you about what to do ... because filling the hole is easy.