Download Product Data
Adheseal Closed Cell Backing Rod is a round, compressible polyethylene foam used behind silicone, polyurethane, hybrid and acrylic sealants. It controls the depth of a sealant bead and prevents adhesion to the base of a joint, allowing the sealant to flex between the two sidewalls rather than tearing under movement.
Choose closed-cell backing rod for construction expansion joints, precast concrete panels, window perimeters and appropriate horizontal joints. Its low water absorption is useful where a joint may encounter dampness, but the foam must be covered by a suitable sealant.
Typical applications
- Precast and tilt-up joints: establishing consistent sealant depth between panels.
- Window and door perimeters: providing a bond breaker behind perimeter seals.
- Concrete and masonry expansion joints: forming the correct sealant profile in moving gaps.
- Horizontal building joints: filling suitable recesses behind cold-applied sealants.
Sizing and installing
Select a rod approximately 25% larger than the joint width where appropriate, so it remains compressed in place. Insert to the depth required by the sealant's joint design. Do not puncture the foam skin or overstretch the rod; puncturing can release trapped gas into curing sealant. Do not leave exposed to UV or use with hot-poured sealants above 70°C. Where a joint cannot accommodate backing rod, use suitable bond-breaker tape.
What size closed-cell backing rod should I use?
Select a diameter about 25% larger than the joint width.
Why is the outer skin important?
Puncturing closed-cell foam can release trapped gas and create bubbles in the curing sealant.
Can it be used above 70°C?
No. Use a heat-resistant backer system specified for hotter sealant applications.
Can it be used in chlorinated pools?
It is not suitable for internal pool joints where chlorine exceeds 5ppm.
- Concrete, masonry, brick and stone joints.
- Metal and aluminium joints.
- Timber, plastics and fibreglass interfaces.
- Painted and powder-coated construction surfaces.
- Compatible waterproofing membrane details.
Adheseal Backing Rod Closed Cell - Round Physical Properties
| Property | Value |
|---|---|
| Density | 0.032 g/cm³ |
| Tensile Strength | 3.2-4.5 kg/cm² |
| compression_set | 0.56-8.0 kg/cm² |
| Elongation | 50% |
| Thermal Conductivity | 0.040 W/m.k |
| Application Temperature | -40°C to +70°C |
| Service Temperature | -40°C |
| Tear Strength | 2.7 kg/cm |
| Shelf Life | 5 years, when stored in cool dry conditions between 10°C and 35°C |
| Chemical Resistance | Excellent to water and detergent solutions; moderate to diluted acids, alkalis, petrol, and oil for short periods |
| Compression Set | 0.56 8.0 Kg/cm2 psi |
| Compressive Strength | 0.56 8.0 Kg/cm2 psi |
| Storage Conditions | Cool Dry between 10ºC and 35ºC keep out of direct sunlight |