Hydrophilic Rubber Strip

Product Description

DE NEEF® SWELLSEAL® 8 is a hydrophilic vulcanized expansive rubber strip for the sealing of joints in underground pre-cast elements, vertical construction joints and concrete - steel joints. DE NEEF® SWELLSEAL® 8 is available in at (Type F) and round (Type R) strips. DE NEEF® SWELLSEAL® 8 is made from a combination of chloroprene rubber and a hydrophilic resin, resulting in good expansion and excellent chemical resistance.

Product Applications

  • Sealing of joints between concrete pre-cast elements 
  • Sealing of vertical construction joints
  • Sealing of pipe penetrations
  • Sealing of concrete-steel joints

Product Advantages

  • High swelling capacity for high pressure applications
  • Good impact resistance
  • Reversible swelling properties
  • Non-sag when correctly placed around pipes and in vertical joints
  • Easily installed by nailing or using DE NEEF® SWELLSEAL® WA
  • Can absorb small movements in joint due to exibility.
  • Chemically resistant*

* Chemical resistance chart available on request.

Packaging & Handling

1 roll = 49.2 ft (15 m) 1 roll = 551 ft (168 m)
1 case = 10 rolls ( 28 lbs) 1 case = 1 roll (30 lbs)

Unlimited shelf life when stored in a dry place in its original packaging.

Installation Guidelines

Prior to the installation of DE NEEF® SWELLSEAL® 8, the surfaces should be levelled, dry, clean and free of oils, dust and laitance.

DE NEEF® SWELLSEAL® 8 can only function properly in a confined space in order to develop sufficient expansion pressure and assure waterproofing.

The expansion of DE NEEF® SWELLSEAL® 8 will create pressure, therefore installation in the middle of the joint is preferred. Concrete cover of at least 6” is required on all sides. DE NEEF® SWELLSEAL® 8 can be applied on both smooth and rough concrete.

On smooth concrete:

Roll the DE NEEF® SWELLSEAL® 8 between the inner and outer rebar and nail down with a gun (4 to 5 nails per yard) or x horizontally with DE NEEF® SWELLSEAL® WA.

On rough concrete:

Gun DE NEEF® SWELLSEAL® WA in a 3/8”bead between inner and outer rebar. Press DE NEEF® SWELLSEAL® 8 firmly into the DE NEEF® SWELLSEAL® WA. Apply extra nailing (4 to 5 nails per yard) in vertical applications.

DE NEEF® SWELLSEAL® 8 Type F and R can be installed around pipes, either by using with DE NEEF® SWELLSEAL® WA by connecting the ends with a steel wire.

Installation during rain or in prolonged contact with water can result in a premature swelling of the strip, which should be avoided. If the DE NEEF® SWELLSEAL® 8 has been exposed to water prior to encapsulating in the concrete, allow it to dry and shrink back to its original configuration. Roll ends are simply butted together to assure a waterproof seal. Do not install in overlap. The strip needs to be in contact with the joint over its full length.

Health and Safety

Always use protective clothing, gloves and goggles consistent with OSHA regulations during use. Avoid eye and skin contact. Do not ingest. Refer to Safety Data Sheet (SDS) for detailed safety precautions SDS’s can be obtained from GCP Applied Technologies or from our web site at


Requires 6” concrete cover on all sides. Avoid installing product during heavy rains.


Typical Properties

Elongation at break 600% 620% ASTM D2240
Shore A Hardness 53 53 ASTM D2240
Specific Density 1.27 1.27 ASTM D471
Expansion in water 580% (1d)
785% (4d)
340% (1d)
720% (4d)
Water Pressure Resistance >65 psi DNCC DNCC
Tensile Strength 1,009 psi< 1,109 psi ASTM D412
Apperarance Green rectangular or round strip of hydrophilic
vulcanized expansive rubber with smooth sides.
Dimensions Type F 1/8” x 3/4”
(3 mm x 20 mm)
Type R 1/4” diam. (6 mm)

Note: The data shown above reflects typical results based on laboratory testing under controlled conditions. Reasonable variations from the data shown above may result.