Rubber hydrophilic waterstop (1)

These generally consist of strips of rubber containing hydrophilic material that when unrestrained will, on contact with water, expand to several times their original volume. When contained in a tied or construction joint, expansion creates a pressure against the concrete face on either side of the joint forming a seal. These materials are not suitable for use in expansion joints or in situations where pressure could move the concrete faces apart or where drying out of the waterstop is possible. Also, some initial leakage may occur as initial swelling is of necessity relatively slow.