diff --git a/include/sqlpp11/data_types/boolean/parameter_type.h b/include/sqlpp11/data_types/boolean/parameter_type.h
index 2e00b1b3..728140d2 100644
--- a/include/sqlpp11/data_types/boolean/parameter_type.h
+++ b/include/sqlpp11/data_types/boolean/parameter_type.h
@@ -35,9 +35,9 @@
 namespace sqlpp
 {
   template <>
-  struct parameter_value_t<boolean> : public base_parameter_value<boolean>
+  struct parameter_value_t<boolean> : public base_parameter_value<boolean, signed char>
   {
-    using base = base_parameter_value<boolean>;
+    using base = base_parameter_value<boolean, signed char>;
     using base::base;
     using base::operator=;
 
diff --git a/include/sqlpp11/data_types/parameter_value_base.h b/include/sqlpp11/data_types/parameter_value_base.h
index 6c55be4e..19785d62 100644
--- a/include/sqlpp11/data_types/parameter_value_base.h
+++ b/include/sqlpp11/data_types/parameter_value_base.h
@@ -32,11 +32,12 @@
 
 namespace sqlpp
 {
-  template <typename DataType>
+  template <typename DataType, typename StorageType = typename DataType::_cpp_value_type>
   struct base_parameter_value
   {
     using _value_type = DataType;
     using _cpp_value_type = typename _value_type::_cpp_value_type;
+    using _cpp_storage_type = StorageType;
 
     base_parameter_value() : _value{}, _is_null{true}
     {
@@ -90,7 +91,7 @@ namespace sqlpp
     }
 
   protected:
-    _cpp_value_type _value;
+    _cpp_storage_type _value;
     bool _is_null;
   };
 }