The duties of the warranty company depend on the language of the warranty. In the warranty you probably waived your right to sue the builder over defects in construction. Take the warranty and all of the paperwork associated with the house to an attorney. If you have major damage, you may have a good action against the builder. Get an attorney to review all of the documents. These suits are not as easy to win as you might think, but only a review of the documents and the facts surrounding the failure of the building can decide how strong you case is. ALso, don't delay on this. THere are statutes of limitation which will keep you from suing should you wait too long. Good luck.