Sill Sealer

Air and Moisture Barrier

Note: Installation instructions and illustrated drawings are recommendations only, while proper local construction methods are the responsibility of the installer.

Made from ribbed polyethylene foam, Reflectix® Sill Sealer was designed to reduce air leakage between the foundation wall and sill plate. The Sill Sealer can also be used to seal around window and door frames.

Recommended Products

Sill Sealer

Ribbed Polyethylene, White – Roll

  • CF3055036 (3.5” x 50’) – 36 rolls
  • CF5055024 (5.5” x 50’) – 24 rolls
  • CF7055016 (7.5” x 50’) – 16 rolls
  • CF9055012 (9.5” x 50’) – 12 rolls


  • Stops heat loss and air infiltration at the foundation to sill plate interface
  • Eliminate costly callbacks to builders due to leaks
  • Mildew and water-resistant
  • Provides protection against sill plate rot
  • Works on residential and commercial construction, slab on grade, crawl spaces or basements
  • Highly durable and can be installed around window and door frames

Installation Instructions

Installation Instruction pdf: PRO Sill Sealer Revised 012021

  • Install a continuous course of the Reflectix® Sill Sealer between the foundation wall (or footing) and the sill plate.
  • The product can also be installed around window and door frames.


Review These Important Safety Guidelines Prior to Installation:

  • ALWAYS check local building codes before installing Reflectix®.
  • ALWAYS check the area you are insulating and make any needed repairs. Any worn wiring should be replaced before you begin installing Reflectix®.
  • ALWAYS make sure work areas are well ventilated and well lighted.
  • ALWAYS use eye protection when operating a staple gun.
  • ALWAYS use caution and common sense when using a staple gun. Be aware of electrical wiring locations. Stapling into a wire can cause severe shock or death. NEVER staple into electrical wiring.
  • ALWAYS be careful when working with large pieces of Reflectix® on windy days.
  • When installing Reflectix® on bright sunny days, it is best to wear sun glasses.
  • Do not work in areas such as attics when temperatures are too hot.
  • Please Note: The intention of these Installation Instructions and 3-D renderings are for the sole purpose of illustrating the correct location and relative position of the Reflectix® products in specific building assemblies. The correct construction methods and techniques are the responsibility of the installer or contractor. The methods outlined are recommendations on location of the Reflectix® products as a guideline. There are no claims on the part of Reflectix, Inc. that these building assemblies are finite standards or meet building code requirements (as they can vary by region).

Testing and Certification

Reflectix® products are thoroughly tested at either nationally approved, independent laboratories or leading universities. Tests are performed to current American Society of Testing and Materials (ASTM) standards when a standard exists. To obtain a copy of our Product Testing Specifications, please refer to the “Additional Resources” tab. The documents are also available by e-mail at or call (800) 879-3645.


Pictured: 1. 3.5″, 5.5 “, 7.5″ and 9.5” Sill Sealer Rolls