diff --git a/Makefile b/Makefile
index 0bfd5ac..cf7a8c0 100644
--- a/Makefile
+++ b/Makefile
@@ -36,9 +36,11 @@ build/imgui.o: src/imgui_inc.cpp
 	$(CXX) -O3 -fPIC -c $(IMGUI_FLAGS) $< -o $@
 
 $(ROOT_IFACE): src/root/RMicroFileReader.cxx
+	@mkdir -p $(@D)/build
 	$(CXX) -O3 -fPIC -c $(ROOTFLAGS) $< -o $@
 
 $(ROOT_IFACE_DBG): src/root/RMicroFileReader.cxx
+	@mkdir -p $(@D)/build
 	$(CXX) -O0 -DDEBUG -g -fPIC -c $(ROOTFLAGS) $< -o $@
 
 # debug build