What should I put on concrete basement walls instead of vapor barrier?
Our basement just got water in it through a window well. We took care of grading and sealing up window etc but I saw the builder put a plastic vapor barrier that is already moldy after a few months.
Putting vapor barriers on basement walls almost always does more harm than good by trapping moisture and causing mold. First I would suggest you see this page to learn about why it happens and how to fix it -
How to prevent mold when finishing a basement
The short story is this - the poly vapor barrier is intended to help but actually does not, as there is no way for moisture to escape as it can't dry to the exterior with a backfilled basement foundation. There are some building inspectors that will still insist on seeing a vapor barrier, so in such a cases we suggest using a 'smart' or 'breathable' vapor retarder membrane to let excess moisture escape.