Closed cell polyethylene backing rod


POLYROD is a closed cell, non absorbent and chemically inert polyethylene foam flexible rod. POLYROD is designed for use as a compressible joint backing material for elastomeric and a wide variety of cold applied joint sealants.


  • Controls joint depths and ensures a proper width to depth ratio
  • Non absorbent surface eliminates three sided adhesion of the elastomeric sealant
  • Forces sealant to have maximum sidewall adhesion
  • Closed cell structure does not allow the absorption of moisture or air
  • Lightweight and compressible. Can easily be accommodated in joints of varying widths
  • Highly resilient. Accommodates dynamic joints
  • Chemically inert
  • Fully compatible with a wide variety of sealants
  • Non-staining
  • Rot proof

This TDS is applicable for the United Arab Emirates only. Please contact your local Polybit sales office for the available TDS in your region

Step by step


The joint surface must be clean, dry and free from oil, loose particles, cement laitance and other contaminants which may affect the adhesion. A thorough wire brushing, grinding, sand blasting or solvent cleaning may be required to expose a clean and sound substrate. on painted surfaces all loosely adhering paint must be removed, if in doubt remove all previous decorations. Remove all round or sharp edges and corners which might perforate or cause damage to the backing rod. The compressible joint filler shall be cut back to expose a uniform joint depth.


Select a backer rod whose diameter is at least 20% larger but not greater than 33% of the joint width. This will ensure that the backer rod remains in compression and in place during sealant installation. The backing rod shall be inserted into the joint by using a blunt tool or roller and forced gently into the joint till the desired depth is achieved, whilst making no damages to the joints & edges.


Do not damage or poke holes in the backer rod during or after installation, since this may cause air bubbles in the sealant and affect its performance. Also, do not fold or overly stretch and compress the backer rod during installation. Ensure that it fits in tight against the sides of the joint.  Polyrod installation shall be done only after the necessary primer has been applied to the edges of the joints.