diff --git a/Sources/HeightStrategy.swift b/Sources/HeightStrategy.swift
index 084018c..f873906 100644
--- a/Sources/HeightStrategy.swift
+++ b/Sources/HeightStrategy.swift
@@ -26,6 +26,8 @@ public protocol CellHeightCalculatable {
 
     func height(row: Row, path: NSIndexPath) -> CGFloat
     func estimatedHeight(row: Row, path: NSIndexPath) -> CGFloat
+    
+    func invalidate()
 }
 
 public class PrototypeHeightStrategy: CellHeightCalculatable {
@@ -63,4 +65,8 @@ public class PrototypeHeightStrategy: CellHeightCalculatable {
     public func estimatedHeight(row: Row, path: NSIndexPath) -> CGFloat {
         return UITableViewAutomaticDimension
     }
+
+    public func invalidate() {
+        cachedHeights.removeAll()
+    }
 }
\ No newline at end of file