Concor Holdings (Pty) Ltd t/a Concor Technicrete v Potgieter

The appellant manufactured and supplied paving stones to a builder under a credit agreement containing a reservation of ownership clause. The appellant knew that the stones were urgently required for use on a building site owned by the respondent, that they were selected to match the building, and that they would be laid as part of the construction works. Some stones were delivered directly to the site and were laid, cut, and embedded, resulting in wastage. The respondent paid the builder for the completed works, including the paving stones, unaware of the reservation of ownership clause. The builder failed to pay the appellant and was sequestrated. The appellant then instituted a rei vindicatio against the respondent for return of the paving stones. The respondent raised estoppel by conduct as a defence.

The appeal was dismissed with costs, and the judgment of the Pretoria High Court upholding the plea of estoppel was confirmed.

The case is a leading authority on estoppel by conduct in South African law, clarifying that a representation by conduct need not be precise or unequivocal. It corrected earlier interpretations suggesting a stricter test and reaffirmed that the focus is on reasonable foreseeability of deception and reasonable reliance. The judgment is particularly important in disputes involving reservation of ownership clauses and rei vindicatio in construction contexts.