diff --git a/cmake/Modules/ExternalCMakeProject.cmake b/cmake/Modules/ExternalCMakeProject.cmake
index 75c33ab99e..7e3681dc28 100644
--- a/cmake/Modules/ExternalCMakeProject.cmake
+++ b/cmake/Modules/ExternalCMakeProject.cmake
@@ -43,5 +43,5 @@ function(ExternalCMakeProject target url hash basedir cmakedir cmakefile)
       "${CMAKE_BINARY_DIR}/_deps/${target}-src/${cmakedir}/CMakeLists.txt")
   endif()
   add_subdirectory("${CMAKE_BINARY_DIR}/_deps/${target}-src/${cmakedir}"
-    "${CMAKE_BINARY_DIR}/_deps/${target}-build")
+    "${CMAKE_BINARY_DIR}/_deps/${target}-build" EXCLUDE_FROM_ALL)
 endfunction(ExternalCMakeProject)
diff --git a/cmake/Modules/Packages/KSPACE.cmake b/cmake/Modules/Packages/KSPACE.cmake
index 6060d4b1db..1fdd898144 100644
--- a/cmake/Modules/Packages/KSPACE.cmake
+++ b/cmake/Modules/Packages/KSPACE.cmake
@@ -91,7 +91,7 @@ if(FFT_USE_HEFFTE)
     string(REPLACE "@Heffte_GIT_HASH@" "(unknown)" HEFFTE_CFG_FILE_TEXT "${HEFFTE_CFG_FILE_TEXT}")
     file(WRITE ${heffte_project_SOURCE_DIR}/include/heffte_config.cmake.h "${HEFFTE_CFG_FILE_TEXT}")
 
-    add_subdirectory(${heffte_project_SOURCE_DIR} ${heffte_project_BINARY_DIR})
+    add_subdirectory(${heffte_project_SOURCE_DIR} ${heffte_project_BINARY_DIR} EXCLUDE_FROM_ALL)
     add_library(Heffte::Heffte ALIAS Heffte)
     if(BUILD_SHARED_LIBS_WAS_ON)
       set(BUILD_SHARED_LIBS ON)