diff --git a/search/Sta.cc b/search/Sta.cc
index b77084e1..f49b4721 100644
--- a/search/Sta.cc
+++ b/search/Sta.cc
@@ -2532,6 +2532,13 @@ Sta::reportClkSkew(ClockSet *clks,
 
 ////////////////////////////////////////////////////////////////
 
+void
+Sta::delaysInvalid()
+{
+  graph_delay_calc_->delaysInvalid();
+  search_->arrivalsInvalid();
+}
+
 void
 Sta::arrivalsInvalid()
 {
diff --git a/search/Sta.hh b/search/Sta.hh
index 76c4c691..f6d1b76b 100644
--- a/search/Sta.hh
+++ b/search/Sta.hh
@@ -894,6 +894,8 @@ public:
   // If full=false update arrivals incrementally.
   // If full=true update all arrivals from scratch.
   void updateTiming(bool full);
+  // Invalidate all delay calculations. Arrivals also invalidated.
+  void delaysInvalid();
   // Invalidate all arrival and required times.
   void arrivalsInvalid();
   void setPathMinMax(const MinMaxAll *min_max) __attribute__ ((deprecated));