The trial court erred in failing to award pre-judgment interest under Civ. Code 3297(a) in this suit for extra compensation under plaintiff’s subcontract to supply expansion joints for a bridge overpass construction project.  The extra compensation was reasonably calculable in amount as it depended solely on the difference in price between cheaper two expansion joint assemblies and the four expansion joint assemblies that the defendant belatedly insisted on.  In both pre-litigation letters and pleadings filed in the litigation, plaintiff informed defendant of the added amount due as a result of the difference between two and four expansion joint assemblies.  The jury awarded exactly the amount that plaintiff claimed was that price difference.

California Court of Appeal, Fifth District (Franson, J.); August 9, 2016 (partial publication); 2016 WL 4212124