Radiant Floor – In a Subfloor


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

Reflectix® has an insulating upgrade available for a radiant floor system installed in a subfloor. The addition of this Reflective Insulation into a radiant floor project will result in a higher level of energy efficiency and a more even floor surface temperature. The bonus characteristic to this product is how easy it is to handle and install.

Recommended Products

Double Reflective Insulation

Reflective/Bubble/Bubble/Reflective – Roll

  • BP48100 (48” x 100’)


  • R-4.6
  • Directs heat into living space
  • Enhances even heat distribution across floor surface
  • Reduces annual energy costs of the system
  • Installs quickly and easily
  • Non-toxic / non-carcinogenic
  • No nesting characteristics for insects

Installation Instructions

Installation Instruction pdf: PRO Rad Fl Subfloor Revised 012021

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

Note: For all methods (retrofit), inspect the structural integrity of the subfloor, and make any needed repairs before installing Reflectix®.

  • Unroll the Reflectix® Reflective Insulation over the existing floor. Cut product flush with the walls.
  • Butt the seams of the product and seal with 2” wide foil tape. Note: Utilize a flat edge taping tool to assure good adhesion on all tape.
  • Install Radiant Floor System per manufacturer’s specifications, sleepers and new (top) subfloor.


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).

Reflectix Fact Sheet per FTC

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. Double Reflective Insulation