diff --git a/pvDataApp/misc/serialize.h b/pvDataApp/misc/serialize.h
index effc763..7fa7559 100644
--- a/pvDataApp/misc/serialize.h
+++ b/pvDataApp/misc/serialize.h
@@ -44,7 +44,7 @@ namespace epics { namespace pvData {
     };
 
 
-    class SerializableArray : public Serializable {
+    class SerializableArray : virtual public Serializable {
     public:
         virtual void serialize(ByteBuffer *buffer,
             SerializableControl *flusher, int offset, int count) = 0;
diff --git a/pvDataApp/pv/pvData.h b/pvDataApp/pv/pvData.h
index 22bade9..639cbc8 100644
--- a/pvDataApp/pv/pvData.h
+++ b/pvDataApp/pv/pvData.h
@@ -58,7 +58,7 @@ public:
 
 class PVField
 : public Requester,
-  public Serializable,
+  virtual public Serializable,
   private NoDefaultMethods
 {
 public: