diff --git a/ValaLibCommonRules.cmake b/ValaLibCommonRules.cmake
index 7a94d4a..45ed3dd 100644
--- a/ValaLibCommonRules.cmake
+++ b/ValaLibCommonRules.cmake
@@ -41,9 +41,13 @@ IF (LibIsPlugin)
 ENDIF (LibIsPlugin)
 
 IF (UNIX)
-  INCLUDE (GNUInstallDirs)
-  #SET (install_dest lib${install_prefix})
-  SET (install_dest ${CMAKE_INSTALL_FULL_LIBDIR}${install_prefix})
+  IF("${CMAKE_SIZEOF_VOID_P}" EQUAL "8")
+    SET (install_dest lib64${install_prefix})
+  ELSE()
+    SET (install_dest lib${install_prefix})
+  ENDIF()
+  #INCLUDE (GNUInstallDirs)
+  #SET (install_dest ${CMAKE_INSTALL_FULL_LIBDIR}${install_prefix})
 ELSEIF (WIN32)
   SET (install_dest bin${install_prefix})
 ENDIF (UNIX)