diff --git a/tox.ini b/tox.ini
index 6f37d00..24e3b5d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -138,6 +138,7 @@
 
 [testenv:docs]
 commands =
+    rm -rf doc/build
     python setup.py build_sphinx {posargs}
 
 [testenv:pep8]
@@ -159,12 +160,14 @@
 # E129 skipped because it is too limiting when combined with other rules
 ignore = E125,E123,E129
 show-source = True
-exclude = .git,.venv,.tox,dist,doc,*egg
+exclude = .git,.venv,.tox,dist,doc,*egg,build
 enable-extensions = H106,H203,H904
 import-order-style = pep8
 
 [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:pip-check-reqs]
 # Do not install test-requirements as that will pollute the virtualenv for