diff --git a/src/ifcparse/IfcWrite.cpp b/src/ifcparse/IfcWrite.cpp
index 3d863f0c36..285fe34fdb 100644
--- a/src/ifcparse/IfcWrite.cpp
+++ b/src/ifcparse/IfcWrite.cpp
@@ -308,6 +308,8 @@ public:
 	int operator()(const double& /*i*/) const { return -1; }
 	int operator()(const std::string& /*i*/) const { return -1; }
 	int operator()(const boost::dynamic_bitset<>& /*i*/) const { return -1; }
+	int operator()(const IfcWriteArgument::empty_aggregate_t&) const { return 0; }
+	int operator()(const IfcWriteArgument::empty_aggregate_of_aggregate_t&) const { return 0; }
 	int operator()(const std::vector<int>& i) const { return (int)i.size(); }
 	int operator()(const std::vector<double>& i) const { return (int)i.size(); }
 	int operator()(const std::vector< std::vector<int> >& i) const { return (int)i.size(); }
@@ -435,6 +437,8 @@ public:
 		}
 		data << ")";
 	}
+	void operator()(const IfcWriteArgument::empty_aggregate_t&) const { data << "()"; }
+	void operator()(const IfcWriteArgument::empty_aggregate_of_aggregate_t&) const { data << "()"; }
 	operator std::string() { return data.str(); }
 };
 
diff --git a/src/ifcparse/IfcWrite.h b/src/ifcparse/IfcWrite.h
index 04a7c6d89f..2d9457474d 100644
--- a/src/ifcparse/IfcWrite.h
+++ b/src/ifcparse/IfcWrite.h
@@ -54,6 +54,8 @@ namespace IfcWrite {
 				: data(data), enumeration_value(enumeration_value) {}
 		};		
 		class Derived {};
+		class empty_aggregate_t {};
+		class empty_aggregate_of_aggregate_t {};
 	private:
 		boost::variant<
 			// A null argument, it will always serialize to $
@@ -85,6 +87,7 @@ namespace IfcWrite {
 			IfcUtil::IfcBaseClass*,
 
 			// AGGREGATES:
+			empty_aggregate_t,
 			// An aggregate of integers, e.g. (1,2,3)
 			std::vector<int>,
 			// An aggregate of floats, e.g. (12.3,4.) 
@@ -99,6 +102,7 @@ namespace IfcWrite {
 			IfcEntityList::ptr,
 
 			// AGGREGATES OF AGGREGATES:
+			empty_aggregate_of_aggregate_t,
 			// An aggregate of an aggregate of ints. E.g. ((1, 2), (3))
 			std::vector< std::vector<int> >,
 			// An aggregate of an aggregate of floats. E.g. ((1., 2.3), (4.))