Can you sue a contractor for using defective materials?

The better question would be whether you're likely to win, as it is simple to sue for most things.

Not knowing any details, this could be a reasonably strong case. Some things to consider would be:

1. Did the contract stipulate any particular type of materials?

2. If not, did the contract stipulate any particular quality of materials?

3. How defective are these materials? Would reasonable neutral parties agree they're defective? Do the defects make what is being built dangerous? Less attractive? Less desirable to you on a personal level?

These are only some of the things that should be considered. If this is more than a hypothetical question, I would recommend talking to an attorney.