Your home builder may have as long as 8 years to warranty or otherwise remain responsible for defects. I think it best to try and go through the home builder first and see what if anything they will resolve. If nothing else you will have an idea of what their posturing or position will be in regards to their liability. Depending on how that meeting goes you will know if they will work with you or if you need to get competent legal representation in real estate or construction defect law.
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I would work with an experienced residential real estate/construction attorney and have your attention contact the home builder. If the builder balks at the claim, you need to review your construction contract to determine if it has any dispute resolution provisions, such as mandatory arbitration. In addition, your damages are not limited to the cost of repair and replacement. They would also include your additional cooling expenses as a result of the builder's errors.
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