diff --git a/external/external_build.cmake b/external/external_build.cmake
index 0bb5b6e..590304f 100644
--- a/external/external_build.cmake
+++ b/external/external_build.cmake
@@ -31,9 +31,10 @@ SET(CONFIGURE_CPP_FLAGS "")
 SET(CONFIGURE_LDFLAGS "")
 
 if (ENABLE_SHARP)
-  SET(DEP_BUILD ${CMAKE_SOURCE_DIR}/sharp-prefix/src/sharp/libsharp/auto)
+  SET(DEP_BUILD ${BUILD_PREFIX}/sharp-prefix/src/sharp/libsharp/auto)
   ExternalProject_Add(sharp
     URL ${CMAKE_SOURCE_DIR}/external/libsharp-6077806.tar.gz
+    PREFIX ${BUILD_PREFIX}/sharp-prefix
     BUILD_IN_SOURCE 1 
     CONFIGURE_COMMAND autoconf && ./configure "CC=${CMAKE_C_COMPILER}" "CXX=${CMAKE_CXX_COMPILER}" --prefix=${DEP_BUILD}
     BUILD_COMMAND ${CMAKE_MAKE_PROGRAM}
@@ -255,12 +256,14 @@ ENDIF(INTERNAL_EIGEN)
 
 
 
-SET(OMPTL_BUILD_DIR ${CMAKE_BINARY_DIR}/omptl-prefix/src/omptl)
+SET(cosmotool_DEPS ${cosmotool_DEPS} omptl)
+SET(OMPTL_BUILD_DIR ${BUILD_PREFIX}/omptl-prefix)
 ExternalProject_Add(omptl
+  PREFIX ${OMPTL_BUILD_DIR}
   URL ${CMAKE_SOURCE_DIR}/external/omptl-20120422.tar.bz2
   CONFIGURE_COMMAND echo "No configure"
   BUILD_COMMAND echo "No build"
-  INSTALL_COMMAND ${CMAKE_COMMAND} -E copy_directory ${OMPTL_BUILD_DIR} ${CMAKE_BINARY_DIR}/external/stage/include/omptl
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E copy_directory ${OMPTL_BUILD_DIR}/src/omptl ${CMAKE_BINARY_DIR}/external/stage/include/omptl
 )
-include_directories(${OMPTL_BUILD_DIR}/..)
+include_directories(${OMPTL_BUILD_DIR}/src/)