Expansion Joint

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

This durable, lightweight, closed-cell, foam expansion joint is the solution for your concrete placement needs. It is flexible and can be utilized for curved or straight applications. Reflectix® Expansion Joint is sealant-friendly working well with a variety of common sealants. Additionally, the product is sturdy and will not prematurely break during job-site handling.

Product Description

Reflectix® Expansion Joint consists of a lightweight closed cell foam. The product is 1/2” wide and available in two widths, 4” and 6”. One of the key features to the Expansion Joint is the “Tear Off” strip that allows for easy caulking subsequent to the curing of the concrete.


  • Easy to handle and install
  • Will not crack or break during installation
  • “Tear Off” strip provides easy caulking subsequent to pour
  • Lightweight – Approx. 10 times lighter than traditional products
  • Sturdy – Will not prematurely break during job site handling
  • Resistant to Moisture – Virtually zero water absorption
  • Termite Resistant – Does not facilitate destructive termites.
  • UV Resistant – Prevents early degradation from the sun
  • Recyclable – Foam is made of recyclable resins
  • Environmentally Friendly – Material is CFC and HCFC-free
  • Temperature Friendly
  • Excellent range for cold or hot climates
  • Reusable – Tear-off strip can be reused as a backer rod
  • Sealant Friendly – Works with a variety of common sealants

Part Numbers and Sizes

  • EXP04050 (4”x 50’)
  • EXP06050 (6”x 50’)

Technical Data

Color: Black • Thickness: 1/2”

Physical Properties — Test Method — Value*

  • Recovery (%) — ASTM D 545 — 97.8
  • Extrusion (in) — ASTM D 545 — 0.12
  • Compressive Strength Vertical Direction (psi) — ASTM D 545-05 Suffix D @ 50% — 14.9
  • Compression Set (%) — ASTM D 3575-00 Suffix B — 18.3
  • Tensile Stress (psi) — ASTM D 3575-00 Suffix T MD/CMD — 103 / 68
  • Tear Resistance (lb/in) — ASTM D 3575-00 Suffix G MD/CMD — 14 / 24
  • Density Range (lb/ft3) — ASTM D 3575 — 2 (nominal)
  • Water Absorption (lb/ft2) — ASTM D 545 — 0.001

Meets Application Requirements of: ASTM D 1752 Sections 5.1-5.4 (with the compression requirement modified to 10 psi minimum and 25 psi maximum.) ASTM D 4819 Type II

* While values shown are typical of these products, they should not be construed as specification limits.

Installation Instructions

Note: Do Not Store In Direct Sun

  • Unroll and cut to length.
  • Attach to adjacent material before pouring concrete. Attachment can be made with construction adhesive, nails or staples. Be sure that the top of the Expansion Joint is at the top of the intended concrete pour.
  • Expansion Joint material includes a built-in “tear-off” strip. The “tear-off” strip should be facing up if caulking is desired after concrete hardens. If no caulking is planned, “tear off” strip should be facing down.
  • Pour concrete and finish. After concrete hardens, if “tear off” strip was placed up, remove strip and seal area with appropriate caulking.

Exceeds ASTM Standard D 7174.


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).


Pictured: 1. 4″ and 6″ Expansion Joint Rolls, 2. Roll showing “tear-off” strip