diff --git a/Makefile b/Makefile
index f55db43d..92670233 100644
--- a/Makefile
+++ b/Makefile
@@ -39,6 +39,8 @@ installheaders::
 	chmod 644 $(HEADER_DIR)/c++/v1/*
 	chmod 755 $(HEADER_DIR)/c++/v1/ext
 	chmod 644 $(HEADER_DIR)/c++/v1/ext/*
+	chmod 755 $(HEADER_DIR)/c++/v1/experimental
+	chmod 644 $(HEADER_DIR)/c++/v1/experimental/*
 
 install::