Abstract: An improved breaker strip for a domestic refrigerating appliance which may be fitted in place prior to the appliance being insulated by an in situ foaming process to prevent foam leakage. First and second mechanical sealing means of a conventional type are provided to seal along the edges of the breaker strip to the appliance walls. An additional flange seal is further provided for each of the first and second sealing means so as to enshroud each means and form a small chamber therebetween and the respective flange seal. Reactive liquid which leaks into the chambers tends to expand to block them prior to any escape of such liquid past the conventional seals, and also to bias the conventional seals into greater sealing contact with the appliance walls.