diff --git a/build-k4.sh b/build-k4.sh
index 8e4396f652b3090f1a906a8d2ff8b435edfe405e..27c6f3570f934f8db68066e5553b65f010d9a68f 100755
--- a/build-k4.sh
+++ b/build-k4.sh
@@ -57,7 +57,7 @@ function run-cmake() {
 
     cd $blddir
 
-    local clhep_prefix=$(clhep-config --prefix)
+    local clhep_prefix=$(eval echo $(clhep-config --prefix))
     local clhep_include=${clhep_prefix}/include
 
     # locate the pandorapfa