diff --git a/src/Val.cc b/src/Val.cc
index 9eb0ef1c2a..a33f022a82 100644
--- a/src/Val.cc
+++ b/src/Val.cc
@@ -2933,7 +2933,7 @@ RecordVal::RecordVal(RecordTypePtr t, bool init_fields) : Val(std::move(t)) {
     if ( init_fields ) {
         record_val.resize(rt->NumFields());
 
-        rt->InitSlots(record_val);
+        rt->InitSlots(std::span{record_val.data(), record_val.size()});
 
         for ( auto& e : rt->CreationInits() ) {
             try {
@@ -2955,11 +2955,10 @@ RecordVal::RecordVal(RecordTypePtr t, bool init_fields) : Val(std::move(t)) {
 RecordVal::RecordVal(RecordTypePtr t, std::vector<std::optional<ZVal>> init_vals) : Val(std::move(t)) {
     // TODO: Change so that callers pass init_vals as ZValSlot instead?
     size_t n = GetRecordType()->NumFields();
-    record_val.reserve(n);
+    record_val.resize(n);
+    GetRecordType()->InitSlots(std::span{record_val.data(), record_val.size()});
 
     for ( size_t i = 0; i < n; i++ ) {
-        record_val.emplace_back(ZValSlot(GetRecordType()->GetFieldType(i)));
-
         if ( init_vals[i].has_value() )
             record_val[i] = init_vals[i].value();
     }
@@ -3009,6 +3008,7 @@ void RecordVal::ResizeParseTimeRecords(RecordType* revised_rt) {
         auto required_length = revised_rt->NumFields();
 
         if ( required_length > current_length ) {
+            rv->record_val.reserve(required_length);
             for ( auto i = current_length; i < required_length; ++i )
                 rv->AppendField(revised_rt->FieldDefault(i), revised_rt->GetFieldType(i));
         }
diff --git a/src/Val.h b/src/Val.h
index 28d5ea87cb..91b248e086 100644
--- a/src/Val.h
+++ b/src/Val.h
@@ -1656,9 +1656,9 @@ protected:
      */
     void AppendField(ValPtr v, const TypePtr& t) {
         if ( v )
-            record_val.emplace_back(ZValSlot(v, t));
+            record_val.push_back(ZValSlot(v, t));
         else
-            record_val.emplace_back(ZValSlot(t));
+            record_val.push_back(ZValSlot(t));
     }
 
     // For internal use by low-level ZAM instructions and event tracing.
@@ -1710,7 +1710,7 @@ private:
     // Low-level values of each of the fields.
     //
     // Lazily modified during GetField(), so mutable.
-    mutable std::vector<ZValSlot> record_val;
+    mutable detail::vector32<ZValSlot> record_val;
 };
 
 class EnumVal final : public detail::IntValImplementation {