diff --git a/tox.ini b/tox.ini
index a1eb5be64c5d0224139952aaf77d97d92b0473d6..52c2144cbd368205be084ae5af96a4245e258f3b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -25,7 +25,7 @@ skipsdist=True
 # Where to write build artefacts. We default to the "build" directory in the
 # tox.ini file's directory. Override with the TOXINI_ARTEFACT_DIR environment
 # variable.
-build_root={env:TOXINI_ARTEFACT_DIR:{toxinidir}/build}
+build_root={env:TOXINI_ARTEFACT_DIR:{toxinidir}/build}/{envname}
 
 [testenv]
 # Which environment variables should be passed into the environment.