diff --git a/hibernate-core/src/main/java/org/hibernate/boot/model/source/internal/hbm/ModelBinder.java b/hibernate-core/src/main/java/org/hibernate/boot/model/source/internal/hbm/ModelBinder.java
index 544c38379a06..490df12f52cc 100644
--- a/hibernate-core/src/main/java/org/hibernate/boot/model/source/internal/hbm/ModelBinder.java
+++ b/hibernate-core/src/main/java/org/hibernate/boot/model/source/internal/hbm/ModelBinder.java
@@ -155,6 +155,7 @@
 import org.hibernate.type.CustomType;
 import org.hibernate.type.ForeignKeyDirection;
 import org.hibernate.type.StandardBasicTypes;
+import org.hibernate.type.internal.BasicTypeImpl;
 import org.hibernate.type.spi.TypeConfiguration;
 import org.hibernate.usertype.CompositeUserType;
 import org.hibernate.usertype.ParameterizedType;
@@ -1877,11 +1878,22 @@ private void resolveLob(final SingularAttributeSourceBasic attributeSource, Simp
 		// Resolves whether the property is LOB based on the type attribute on the attribute property source.
 		// Essentially this expects the type to map to a CLOB/NCLOB/BLOB sql type internally and compares.
 		if ( !value.isLob() && value.getTypeName() != null ) {
-			final BasicType<?> basicType = attributeSource.getBuildingContext()
-					.getMetadataCollector()
-					.getTypeConfiguration()
-					.getBasicTypeRegistry()
-					.getRegisteredType( value.getTypeName() );
+			BasicType<?> basicType = null;
+
+			if ( value.getTypeName().startsWith( BasicTypeImpl.EXTERNALIZED_PREFIX ) ) {
+				basicType = attributeSource.getBuildingContext()
+						.getBootstrapContext()
+						.resolveAdHocBasicType( value.getTypeName() );
+			}
+
+			if ( basicType == null ) {
+				basicType = attributeSource.getBuildingContext()
+						.getMetadataCollector()
+						.getTypeConfiguration()
+						.getBasicTypeRegistry()
+						.getRegisteredType( value.getTypeName() );
+			}
+
 			if ( basicType instanceof AbstractSingleColumnStandardBasicType ) {
 				if ( isLob( basicType.getJdbcType().getDdlTypeCode(), null ) ) {
 					value.makeLob();