DE NEEF® Swellseal® 8

Hydrophilic Rubber Strip

Product Description

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.

SWELLSEAL® 8 is available in at (Type F) and round (Type R) strips. 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 SWELLSEAL® WA
  • Can absorb small movements in joint due to exibility.
  • Chemically resistant*

* Chemical resistance chart available on request.


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.

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 SWELLSEAL® 8, the surfaces should be levelled, dry, clean and free of oils, dust and laitance.

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

The expansion of 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. SWELLSEAL® 8 can be applied on both smooth and rough concrete.

On smooth concrete:

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

On rough concrete:

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

SWELLSEAL® 8 Type F and R can be installed around pipes, either by using with 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 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.


Requires 6” concrete cover on all sides. Avoid installing product during heavy rains. | North America customer service: 1-877-4AD-MIX (1-877-423-6491)

We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations, and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation, or suggestion is intended for any use that would infringe any patent, copyright, or other third party right.

DE NEEF and SWELLSEAL are trademarks, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

© Copyright 2018 GCP Applied Technologies Inc. All rights reserved.

GCP Applied Technologies Inc., 2325 Lakeview Parkway, Suite 475, Alpharetta, GA 30009, USA
GCP Canada, Inc., 294 Clements Road, West, Ajax, Ontario, Canada L1S 3C6.
This document is only current as of the last updated date stated below and is valid only for use in the Canada. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2024-06-21