diff --git a/rbc/heavydb/buffer.py b/rbc/heavydb/buffer.py
index ac3f1fdc..0e3e6e81 100644
--- a/rbc/heavydb/buffer.py
+++ b/rbc/heavydb/buffer.py
@@ -32,6 +32,7 @@
 from rbc import typesystem
 from rbc.targetinfo import TargetInfo
 
+from .allocator import allocate_varlen_buffer
 from .metatype import HeavyDBMetaType
 
 int8_t = ir.IntType(8)
@@ -209,7 +210,10 @@ def heavydb_buffer_constructor(context, builder, sig, args):
     ptr = memalloc(context, builder, ptr_type, element_count, element_size)
 
     llty = context.get_value_type(sig.return_type.dtype)
-    st_ptr = builder.alloca(llty)
+    st_size = context.get_abi_sizeof(llty)
+    st_ptr = builder.bitcast(allocate_varlen_buffer(builder, int64_t(st_size),
+                                                    int64_t(1)),
+                             llty.as_pointer())
 
     zero, one, two = int32_t(0), int32_t(1), int32_t(2)
     builder.store(ptr, builder.gep(st_ptr, [zero, zero]))
diff --git a/rbc/heavydb/text_encoding_none.py b/rbc/heavydb/text_encoding_none.py
index b760261c..e60305e6 100644
--- a/rbc/heavydb/text_encoding_none.py
+++ b/rbc/heavydb/text_encoding_none.py
@@ -15,9 +15,9 @@
 
 from rbc import typesystem
 
+from .allocator import allocate_varlen_buffer
 from .array import ArrayPointer
 from .buffer import Buffer, HeavyDBBufferType, heavydb_buffer_constructor
-from .allocator import allocate_varlen_buffer
 
 i8 = ir.IntType(8)
 i8p = i8.as_pointer()
@@ -176,7 +176,10 @@ def text_encoding_none_unicode_ctor(context, builder, sig, args):
     uni_str = context.make_helper(builder, sig.args[0], value=args[0])
 
     llty = context.get_value_type(sig.return_type.dtype)
-    st_ptr = builder.alloca(llty)
+    st_size = context.get_abi_sizeof(llty)
+    st_ptr = builder.bitcast(allocate_varlen_buffer(builder, int64_t(st_size),
+                                                    int64_t(1)),
+                             llty.as_pointer())
     zero, one, two = i32(0), i32(1), i32(2)
 
     eq = builder.icmp_signed('==', uni_str.length, uni_str.length.type(0))