What’s the difference between AAMA 450 and AAMA 101?
AAMA 101 is specific to individual windows and is a nationwide requirement. It does not specify anything for mulled products. The AAMA 450 standard was created specifically for mulled products. It only regulates non-integral mullions, or H-mulls and has only been adopted by eleven states to date. T-mulled units are certified to AAMA 101 and do not require AAMA 450 compliance due to their continuous head and sill construction. Q: Are there differences in the ways different manufacturers mull units? A: Yes. At Simonton, factory mulling uses a multitude of products such as: silicone, reinforcements, steel strapping and screws. This is to assure the strongest possible mulled unit that can meet AAMA codes. Q: What (if any) are the advantages of getting a factory mulled unit versus field mulling a unit? A: Experience says that factory mulling is better because of the amount of reinforcing materials used and the experience of the people performing the work. In field mulling, you sometimes ris
