Hello Daniel, Thank you for your review. We are very sorry to learn that your vanity top developed a hairline crack. Although damages are not covered under our Limited Lifetime Warranty, and you feel like what you are experiencing is due to a manufacturer defect, if you are able to do so, we would like to ask that you reach out to our Customer Care team so that we may review your experience with our quality leaders. You may reach out to our Customer Care team by e-mailing them at CustomerCareWC@masterbrand.com; we ask that if you choose to reach out that you do clarify in the subject line that you were directed to reach out. Nevertheless, please know that we value your feedback and plan to use your review as a guide towards actively improving our products and customer experience. Best Regards.