diff --git a/tox.ini b/tox.ini
index d84274256..e46ce0e37 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,7 +29,9 @@ commands =
     diff-cover --fail-under 100 --compare-branch master coverage.xml
 
 [testenv:releasenotes]
-commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
+commands =
+  rm -rf releasenotes/build
+  sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:pep8]
 sitepackages = False
@@ -71,12 +73,14 @@ whitelist_externals = rm
 # This environment is called from CI scripts to test and publish
 # the API Guide to developer.openstack.org.
 commands =
+  rm -rf api-guide/build
   sphinx-build -W -b html -d api-guide/build/doctrees api-guide/source api-guide/build/html
 
 [testenv:api-ref]
 # This environment is called from CI scripts to test and publish
 # the API Ref to developer.openstack.org.
 commands =
+  rm -rf api-ref/build
   sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
 
 [testenv:functional]