Warranty Issue On New Construction Home - Florida

Location: Florida

My fiancé and I purchased a new construction home from a well-known builder. Our home inspector found no major problems at closing. We had a follow-up inspection before the one-year warranty was up and mold was found to be growing on the trusses in our attic. The builder confirmed and admitted in writing that the mold was present at or before installation, and they should have caught it before they installed them in the house.

We’ve been going back and forth with them for several months about resolving. They had agreed that they are responsible for cleaning the mold under the warranty, but the two outstanding issues were (1) the method of cleaning and (2) what continued responsibility they would have, if any, following the cleaning, if there were recurrences. We have come to an agreement on the method of cleaning, and they’ve agreed to use a product that will allegedly kill the mold after one or maybe two applications at most. However, the builder refuses to provide more than a two-year warranty for recurrences.

Our position is that they negligently installed mold in our new house; we can never truly be 100% confident the trusses will be restored to a mold-free condition no matter what method they use to clean it. Short of replacing all the trusses entirely, the condition threatens to recur for the life of the house, so we believe a lifetime warranty is appropriate. If the builder is as confident as they claim to be about the product they intend to use, then they shouldn’t have any exposure, so an extended warranty won’t give them any risk at all. If their method doesn’t work, they should be responsible for repairing any and all mold recurrences in the same locations, absent intervening causes.

We are now preparing to go to mediation on the issue of their after-treatment responsibility, and our two biggest questions are:
1. Are we being unreasonable in our position that they should offer a lifetime warranty in this situation?
2. Since we have agreed on the method of remediation, and both parties are under a duty to mitigate damages, should we offer to let them do the remediation without prejudice to claims regarding after-remediation responsibility and liability? Are there any downsides to letting them come do the remediation before the lingering issue of the continued warranty is ultimately resolved?