diff --git a/src/ifcparse/IfcEntityInstanceData.cpp b/src/ifcparse/IfcEntityInstanceData.cpp
index ac340d67fb..50fdc253cf 100644
--- a/src/ifcparse/IfcEntityInstanceData.cpp
+++ b/src/ifcparse/IfcEntityInstanceData.cpp
@@ -529,8 +529,6 @@ template IFC_PARSE_API void rocks_db_attribute_storage::set<Derived>(void* stora
 template IFC_PARSE_API void rocks_db_attribute_storage::set<empty_aggregate_t>(void* storage, const IfcParse::declaration* decl, std::size_t identity, size_t index, const empty_aggregate_t& value);
 template IFC_PARSE_API void rocks_db_attribute_storage::set<empty_aggregate_of_aggregate_t>(void* storage, const IfcParse::declaration* decl, std::size_t identity, size_t index, const empty_aggregate_of_aggregate_t& value);
 
-
-
 template IFC_PARSE_API bool rocks_db_attribute_storage::has<Blank>(void* storage, const IfcParse::declaration* decl, std::size_t identity, size_t index) const;
 template IFC_PARSE_API bool rocks_db_attribute_storage::has<int>(void* storage, const IfcParse::declaration* decl, std::size_t identity, size_t index) const;
 template IFC_PARSE_API bool rocks_db_attribute_storage::has<bool>(void* storage, const IfcParse::declaration* decl, std::size_t identity, size_t index) const;
@@ -554,4 +552,17 @@ template IFC_PARSE_API bool rocks_db_attribute_storage::has<Derived>(void* stora
 template IFC_PARSE_API bool rocks_db_attribute_storage::has<empty_aggregate_t>(void* storage, const IfcParse::declaration* decl, std::size_t identity, size_t index) const;
 template IFC_PARSE_API bool rocks_db_attribute_storage::has<empty_aggregate_of_aggregate_t>(void* storage, const IfcParse::declaration* decl, std::size_t identity, size_t index) const;
 
+template <typename T>
+T* InstanceData::get_storage_of_type() const {
+    return std::visit([this](auto& m) -> T* {
+        if constexpr (std::is_same_v<std::decay_t<decltype(m)>, T>) {
+            return &m;
+        }
+        return nullptr;
+    }, file()->storage_);
+}
+
+template IFC_PARSE_API IfcParse::impl::in_memory_file_storage* InstanceData::get_storage_of_type<IfcParse::impl::in_memory_file_storage>() const;
+template IFC_PARSE_API IfcParse::impl::rocks_db_file_storage* InstanceData::get_storage_of_type<IfcParse::impl::rocks_db_file_storage>() const;
+
 #endif
\ No newline at end of file
diff --git a/src/ifcparse/InstanceData.h b/src/ifcparse/InstanceData.h
index 00e54b0f27..7d511cb10d 100644
--- a/src/ifcparse/InstanceData.h
+++ b/src/ifcparse/InstanceData.h
@@ -424,15 +424,7 @@ class IFC_PARSE_API InstanceData {
     uint32_t id_;
 
     template <typename T>
-    T* get_storage_of_type() const {
-        return std::visit([this](auto& m) -> T* {
-            if constexpr (std::is_same_v<std::decay_t<decltype(m)>, T>) {
-                return &m;
-            }
-            return nullptr;
-        },
-                          file()->storage_);
-    }
+    T* get_storage_of_type() const;
 
   public:
       // Since rocks_db_attribute_storage has no members this is not a variant<in_memory, rocks> but in_memory*, where nullptr means a rocks_db_attribute_storage is constructed on the fly given the context from instance data.