diff --git a/Makefile b/Makefile
index 4123d78..ab2be13 100644
--- a/Makefile
+++ b/Makefile
@@ -21,7 +21,7 @@ test-heroku-18:
 buildenv-heroku-16:
 	@echo "Creating build environment (heroku-16)..."
 	@echo
-	@docker build --pull -t python-buildenv-heroku-16 .
+	@docker build --pull -f $(shell pwd)/builds/heroku-16.Dockerfile -t python-buildenv-heroku-16 .
 	@echo
 	@echo "Usage..."
 	@echo
@@ -34,7 +34,7 @@ buildenv-heroku-16:
 buildenv-heroku-18:
 	@echo "Creating build environment (heroku-18)..."
 	@echo
-	@docker build --pull -f Dockerfile.heroku-18 -t python-buildenv-heroku-18 .
+	@docker build --pull -f $(shell pwd)/builds/heroku-18.Dockerfile -t python-buildenv-heroku-18 .
 	@echo
 	@echo "Usage..."
 	@echo