diff --git a/scripts/run_buildkite.sh b/scripts/run_buildkite.sh
index f1e9948..b8b848d 100755
--- a/scripts/run_buildkite.sh
+++ b/scripts/run_buildkite.sh
@@ -17,7 +17,12 @@ set -eux
 
 #folder where this script is stored.
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
-export WORKSPACE=$BUILDKITE_BUILD_PATH
+export WORKSPACE=${BUILDKITE_BUILD_PATH}
+
+# create a clean build folder
+BUILD_DIR=${BUILDKITE_BUILD_PATH}/build
+rm -rf ${BUILD_DIR} || true
+mkdir -p ${BUILD_DIR}
 
 echo "--- CMake"
 ${DIR}/run_cmake.sh