diff --git a/conf/proj.yaml b/conf/proj.yaml
index a656ebb947bb6cfe999b790e22c24f01424b3945..deb4cf28dfcece1a436add2ad83ae1ad2179df57 100644
--- a/conf/proj.yaml
+++ b/conf/proj.yaml
@@ -1,6 +1,7 @@
 spack:
   url: git@gitlab.physik.uni-muenchen.de:LDAP_rbg/spack.git
   branch: lmu/ubuntu20.04-icon
+  compiler: gcc%11.3.0
 
 icon:
   version: 2.6.4-nwp3
diff --git a/templates/build_icon.sh b/templates/build_icon.sh
index f15c3bf1fbf8e8bd6463eea9632f5de0e42d63f6..7e78413c3680e2ad78e7e954db0d1403d606a535 100644
--- a/templates/build_icon.sh
+++ b/templates/build_icon.sh
@@ -4,6 +4,7 @@ WORKDIR=%HPCROOTDIR%
 ICON_VERSION=%ICON_VERSION%
 SPACK_URL=%spack.url%
 SPACK_BRANCH=%spack.branch%
+SPACK_COMPILER=%spack.compiler%
 
 
 # If the workdir directory does not exist create it
@@ -24,14 +25,12 @@ fi
 # Setup the environment
 source ${SPACK_ENV}
 
-# If the model is not installed, install it.
-if [ $( spack find icon-nwp@${ICON_VERSION} &> /dev/null ; echo $? ) -ne 0 ]; then
-  spack install icon-nwp@${ICON_VERSION} ^mpi+slurm
-fi
 
 if [ $( spack find icon-nwp@${ICON_VERSION} &> /dev/null ; echo $? ) -ne 0 ]; then
         echo "Installing icon-nwp@${ICON_VERSION}."
-        spack install icon-nwp@${ICON_VERSION}
+        # Compile openmpi with schedulers=slurm
+        spack install openmpi${SPACK_COMPILER}+legacylaunchers schedulers=slurm
+        spack install icon-nwp@${ICON_VERSION}%${SPACK_COMPILER} ^openmpi%${SPACK_COMPILER}
 else
         echo "icon-nwp@${ICON_VERSION} already installed!"
 fi