diff --git a/MANIFEST.in b/MANIFEST.in
index 216df265b5..981698143f 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -24,5 +24,7 @@ recursive-include synapse/static *.js
 
 exclude jenkins.sh
 exclude jenkins*.sh
+exclude jenkins*
+recursive-exclude jenkins *.sh
 
 prune demo/etc
diff --git a/jenkins-dendron-postgres.sh b/jenkins-dendron-postgres.sh
index f715cd559a..e6e94cc8bc 100755
--- a/jenkins-dendron-postgres.sh
+++ b/jenkins-dendron-postgres.sh
@@ -22,24 +22,10 @@ export PEP8SUFFIX="--output-file=violations.flake8.log || echo flake8 finished w
 
 rm .coverage* || echo "No coverage files to remove"
 
-tox --notest -e py27
+./jenkins/prepare_synapse.sh
 
-TOX_BIN=$WORKSPACE/.tox/py27/bin
-python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
-$TOX_BIN/pip install psycopg2
-$TOX_BIN/pip install lxml
-
-: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
-
-if [[ ! -e .dendron-base ]]; then
-    git clone https://github.com/matrix-org/dendron.git .dendron-base --mirror
-else
-    (cd .dendron-base; git fetch -p)
-fi
-
-rm -rf dendron
-git clone .dendron-base dendron --shared
-cd dendron
+./jenkins/clone.sh sytest https://github.com/matrix-org/sytest.git
+./jenkins/clone.sh dendron https://github.com/matrix-org/dendron.git
 
 : ${GOPATH:=${WORKSPACE}/.gopath}
 if [[ "${GOPATH}" != *:* ]]; then
@@ -48,35 +34,26 @@ if [[ "${GOPATH}" != *:* ]]; then
 fi
 export GOPATH
 
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
+cd dendron
 
 go get github.com/constabulary/gb/...
 gb generate
 gb build
 
-cd ..
-
-
-if [[ ! -e .sytest-base ]]; then
-  git clone https://github.com/matrix-org/sytest.git .sytest-base --mirror
-else
-  (cd .sytest-base; git fetch -p)
-fi
-
-rm -rf sytest
-git clone .sytest-base sytest --shared
-cd sytest
-
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
+cd ../sytest
 
 : ${PORT_BASE:=20000}
 : ${PORT_COUNT=100}
+export PORT_BASE
+export PORT_COUNT
 
 ./jenkins/prep_sytest_for_postgres.sh
 
 mkdir -p var
 
 echo >&2 "Running sytest with PostgreSQL";
+
+TOX_BIN=$WORKSPACE/.tox/py27/bin
 ./jenkins/install_and_run.sh --python $TOX_BIN/python \
                              --synapse-directory $WORKSPACE \
                              --dendron $WORKSPACE/dendron/bin/dendron \
diff --git a/jenkins-postgres.sh b/jenkins-postgres.sh
index 7a43df0d58..edf61a45bb 100755
--- a/jenkins-postgres.sh
+++ b/jenkins-postgres.sh
@@ -22,37 +22,26 @@ export PEP8SUFFIX="--output-file=violations.flake8.log || echo flake8 finished w
 
 rm .coverage* || echo "No coverage files to remove"
 
-tox --notest -e py27
+./jenkins/prepare_synapse.sh
 
-TOX_BIN=$WORKSPACE/.tox/py27/bin
-python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
-$TOX_BIN/pip install psycopg2
-$TOX_BIN/pip install lxml
-
-: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
-
-if [[ ! -e .sytest-base ]]; then
-  git clone https://github.com/matrix-org/sytest.git .sytest-base --mirror
-else
-  (cd .sytest-base; git fetch -p)
-fi
-
-rm -rf sytest
-git clone .sytest-base sytest --shared
-cd sytest
-
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
+./jenkins/clone.sh sytest https://github.com/matrix-org/sytest.git
 
 : ${PORT_BASE:=20000}
 : ${PORT_COUNT=100}
+export PORT_BASE
+export PORT_COUNT
+
+cd sytest
 
 ./jenkins/prep_sytest_for_postgres.sh
 
 echo >&2 "Running sytest with PostgreSQL";
+
+TOX_BIN=$WORKSPACE/.tox/py27/bin
 ./jenkins/install_and_run.sh --coverage \
                              --python $TOX_BIN/python \
                              --synapse-directory $WORKSPACE \
-                             --port-range ${PORT_BASE}:$((PORT_BASE+PORT_COUNT-1)) \
+                             --port-range ${PORT_BASE}:$((PORT_BASE+PORT_COUNT-1))
 
 cd ..
 cp sytest/.coverage.* .
diff --git a/jenkins-sqlite.sh b/jenkins-sqlite.sh
index 27e61af6ee..1c3530ebb3 100755
--- a/jenkins-sqlite.sh
+++ b/jenkins-sqlite.sh
@@ -4,6 +4,7 @@ set -eux
 
 : ${WORKSPACE:="$(pwd)"}
 
+export WORKSPACE
 export PYTHONDONTWRITEBYTECODE=yep
 export SYNAPSE_CACHE_FACTOR=1
 
@@ -22,28 +23,18 @@ export PEP8SUFFIX="--output-file=violations.flake8.log || echo flake8 finished w
 
 rm .coverage* || echo "No coverage files to remove"
 
-tox --notest -e py27
-TOX_BIN=$WORKSPACE/.tox/py27/bin
-python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
-$TOX_BIN/pip install lxml
+./jenkins/prepare_synapse.sh
 
-: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
-
-if [[ ! -e .sytest-base ]]; then
-  git clone https://github.com/matrix-org/sytest.git .sytest-base --mirror
-else
-  (cd .sytest-base; git fetch -p)
-fi
-
-rm -rf sytest
-git clone .sytest-base sytest --shared
-cd sytest
-
-git checkout "${GIT_BRANCH}" || (echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop" ; git checkout develop)
+./jenkins/clone.sh sytest https://github.com/matrix-org/sytest.git
 
 : ${PORT_BASE:=20000}
 : ${PORT_COUNT=100}
+export PORT_BASE
+export PORT_COUNT
 
+cd sytest
+
+TOX_BIN=$WORKSPACE/.tox/py27/bin
 ./jenkins/install_and_run.sh --coverage \
                              --python $TOX_BIN/python \
                              --synapse-directory $WORKSPACE \
diff --git a/jenkins/clone.sh b/jenkins/clone.sh
new file mode 100755
index 0000000000..f56d076ea9
--- /dev/null
+++ b/jenkins/clone.sh
@@ -0,0 +1,24 @@
+#! /bin/bash
+
+NAME=$1
+PROJECT=$2
+BASE=".$NAME-base"
+
+# update our clone
+if [ ! -d .$NAME-base ]; then
+  git clone $PROJECT $BASE --mirror
+else
+  (cd $BASE; git fetch -p)
+fi
+
+rm -rf $NAME
+git clone $BASE $NAME --shared
+
+: ${GIT_BRANCH:="origin/$(git rev-parse --abbrev-ref HEAD)"}
+cd $NAME
+# check out the relevant branch
+git checkout "${GIT_BRANCH}" || (
+    echo >&2 "No ref ${GIT_BRANCH} found, falling back to develop"
+    git checkout "origin/develop"
+)
+git clean -df .
diff --git a/jenkins/prepare_synapse.sh b/jenkins/prepare_synapse.sh
new file mode 100755
index 0000000000..237223c81b
--- /dev/null
+++ b/jenkins/prepare_synapse.sh
@@ -0,0 +1,19 @@
+#! /bin/bash
+
+cd "`dirname $0`/.."
+
+TOX_DIR=$WORKSPACE/.tox
+
+mkdir -p $TOX_DIR
+
+if ! [ $TOX_DIR -ef .tox ]; then
+    ln -s "$TOX_DIR" .tox
+fi
+
+# set up the virtualenv
+tox -e py27 --notest -v
+
+TOX_BIN=$TOX_DIR/py27/bin
+python synapse/python_dependencies.py | xargs -n1 $TOX_BIN/pip install
+$TOX_BIN/pip install lxml
+$TOX_BIN/pip install psycopg2