diff --git a/CMakeLists.txt b/CMakeLists.txt
index a536ebc4..c4d8b0dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -763,8 +763,8 @@ if(MSVC)
 
   # Compile the static lib with debug information included
   # note: we assume here that the default flags contain some /Z flag
-  string(REGEX REPLACE "/Z.[^:]" "/Z7" CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
-  string(REGEX REPLACE "/Z.[^:]" "/Z7" CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
+  string(REGEX REPLACE "/Z.[^:]" "/Z7 " CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
+  string(REGEX REPLACE "/Z.[^:]" "/Z7 " CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
 
   # Optimization flags.
   # http://msdn.microsoft.com/en-us/magazine/cc301698.aspx