Here at MI Windows, we understand that mulling windows in the field may sometimes be preferred for a project. As a result, we can get questions about what is covered under warranty when field mulling occurs. First of all, we do honor the warranty in situations in which nonconformities occur that are not caused in whole or part by the mulling. For example, a seal failure in the insulated glass unit or a broken lock are generally not caused by field mulling – though the final decision has to be made on an individual basis – and coverage under the warranty thus remains available.
However, there are circumstances in which an issue will not be covered by the warranty. As a case in point, the MI warranty does exclude coverage for failures caused in whole or part by the field-mulling process. For example, water intrusion through a field mull or a window frame cracked during the field-mulling process would not be covered by the warranty.
We hope this post has been helpful in answering your questions and concerns. If you need more information, please contact MI Customer Care at 717-365-2500.
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