Moistop® Sealant

Two-in-one STPE that is flexible and durable

Moistop® Sealant

The primary cause of water intrusion is the lack of properly integrated flashing around windows, doors and other fenestrations. The cost of these repairs and potential exposure to litigation can be staggering, particularly when water leakage leads to problems with mold and mildew. Moistop Sealant can be used as both a sealant and flashing, providing a multi-tasking solution for improved weatherization effectiveness and jobsite efficiency.

Completely Compatible Moisture Resistant Sealant
Moistop Sealant is an advanced polymer designed to be compatible with virtually all building materials. Moistop delivers excellent adhesion, compatibility, durability and moisture resistance to prevent door and window water leaks, and the expensive callbacks they cause. It is also suitable for use in construction joints up to one inch in width. Moistop exceeds ASTM C920 and AAMA 808.3-92 (Exterior Perimeter Sealing Compounds) standards.

Dual Purpose for Convenience on the Jobsite
Moistop Sealant can also be used as a liquid flashing to provide gap-free protection to rough and irregular surfaces. It is particularly useful for smaller jobs such as applying flashing to curved intrusions like vents and plumbing.  It is also highly effective with masonry window and door installations. In these instances, there is no need to spend the time or money to bring a separate product onto the jobsite.  Where specified as a liquid applied flashing, the product exceeds AAMA 714 standards. And even though Moistop is tough enough to repair torn vapor barriers, it is smooth enough to take paint in visible application areas.

Part of the Fortifiber® 1-2-3 moisture control system, Moistop Sealant is designed to withstand the rigors of the jobsite and the elements, and is backed by an industry-leading 15-year warranty.


  • Strong, flexible, durable and paintable
  • Adheres to most surfaces and conforms to any shape
  • STPE formulation; low VOC
  • Fewer products needed on jobsite, reducing waste
  • Part of a complete moisture control system
  • Vapor permeable


  • 10.1 fl. oz.
  • 20 fl. oz.

Related products to qualify for the 15 year warranty