diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 138c40070b..4c464d17c1 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -837,6 +837,7 @@ private:
 
 DerivationGoal::DerivationGoal(const Path & drvPath, Worker & worker)
     : Goal(worker)
+    , useChroot(false)
 {
     this->drvPath = drvPath;
     state = &DerivationGoal::init;